Class 12 Medical Biology - Human Reproduction

Write two major functions of testis.

Testis contains numerous Sertoli cells. These form seminiferous tubules. These tubules perform the function of producing sperms, maintaining and storing them.
Located near the Sertoli cells are Leydig's cells. These cells release male sex hormones. Under the effect of LH ( Luteinizing Hormone), these cells release androgen and testosterone.
Testis is the primary male sex organ involved in the process of copulation.

What is parturition? Which hormones are involved in induction of parturition?

The process of giving birth to a baby is called parturition. It means delivering the placenta from the uterus to the outside through the vagina. During parturition, placental movements occur, myometrium contracts and levels of oxytocin increase. Thus the baby is pushed forwards. During parturition, the levels of oxytocin and relaxin hormones increase. Prostaglandins are also increasingly released to im=ncrease the blood flow.

The female is in the reproductive phase between menarche and_________

The female is in the reproductive phase between menarche and menopause.

Name the body part in which the embryo develops.

Inside the uterus, the blastocyst implants in the wall of the uterus, where it develops into an embryo attached to a placenta and surrounded by fluid filled membranes. The embryo develops within the amniotic sac, under the lining of the uterus on one side. This stage is characterized by the formation of most internal organs and external body structures. Most organs begin to form about 3 weeks after fertilization, which equals 5 weeks of pregnancy.

Define zygote.

Zygote is defined as an eukaryotic cell formed by a fertilization event between two gametes. The DNA material from the two cells is combined in the resulting zygote.

Seminal vesicles are located near the ampullae of the vasa deferentia. They do not store sperms. They contribute yellowish, slightly alkaline, a viscous seminal fluid that contains the sugar fructose, a coagulating enzyme, ascorbic acid, and hormone-like prostaglandins. Type 1 for true and 0 for flase

Seminal vesicles: They are located near the ampullae of the vasa deferentia. They do not store sperms. They contribute yellowish, slightly alkaline, viscous seminal fluid that contains the sugar fructose, a coagulating enzyme, ascorbic acid and hormone like prostaglandins.

Each question contains statements given in two columns which have to be matched. Statements in column have to be matched with statements in column II.

Ovary produces ovum in female reproductive system.
Oviduct carries ovary to uterus.
Uterus contains developing foetus while pregnancy.
Vagina receives penis during sexual intercourse.

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What is a menstrual cycle?

Menstruation is the cyclic discharge of unfertilized egg, debris, tissues from the uterus along with blood.

The menstrual cycle is of 28 days and can be divided into 4 phases on the basis of events occurring. Menstrual, follicular, ovulatory, and luteal are 4 phases.

Menstrual phase: This occurs when fertilization of the egg doesn’t take place. As there is no fertilization and implantation of the egg, the uterine lining sheds.
The bleeding lasts for 4-5 days. In this phase level of oestrogen and progesterone decrease.

Proliferative / Follicular phase: In this phase follicles in the ovary matures. The mature ovum is ready for ovulation by the end of this phase.
During this phase, the pituitary starts releasing FSH (Follicular stimulating hormone.

Ovulatory phase: Mature ovum is released from the ovary. This occurs on the 14th day (+/- 1) of the cycle.
Fertilization occurs at this stage of the cycle. In this phase, an increasing level of oestrogen triggers the release of luteinizing hormone (LH).

Secretory/ Luteal phase:
In this phase- The fate of the corpus luteum is decided. If fertilization occurs – it's maintained.
If fertilization doesn’t occur then the corpus luteum has degenerated. In this phase, luteinizing hormone and follicle-stimulating hormone levels decline.
The ruptured follicle seals after delivering the egg and develops a corpus luteum, which delivers progesterone. The oestrogen level is also high.

What is menopause?

Menopause is a gradual decrease in the menstrual cycle. As women age increases or reaches nearly to 40s there is a gradual decrease in the function of ovaries and production of estrogen. Menopausal symptoms are hot flashes, night sweats, pain during intercourse, increased anxiety or irritability and frequent urination. Risks of menopause are high cholesterol formation, breast cancer, osteoporosis risk and also heart diseases.

Schematically represent and explain the events of spermatogenesis in humans.

a. In a testis at puberty, spermatogonia produce sperms by the process of spermatogenesis.
b. The spermatogonia multiply by mitotic division and increase in numbers.
c. Each spermatogonium is diploid and contains 46 chromosomes.
d. Some of the spermatogonia called primary spermatocytes periodically undergo meiosis.
e. A primary spermatocyte completes the first meiotic division (reduction division) leading to formation of two equal haploid cells called secondary spermatocytes having only 23 chromosomes each.
f. The secondary spermatocytes undergo the second meiotic division to produce four equal, haploid spermatids.
g. The spermatids are transformed into spermatozoa (sperms) by the process, called spermiogenesis.

Describe the path that sperm take while leaving the body.

Testes -> Epididymis -> Vas deferens -> Urethra -> Vagina -> Cervix -> Uterus -> Fallopian tube.

What do the sperms do after being released?

The sperms swim in the oviduct to rich the egg. When they rich the egg one of the sperm may fuse to egg to form zygote.

In which female reproductive organ does the embryo get embedded?

The process in which the embryo gets embedded in the uterine wall is called implantation.
Embryo gets implanted at the blastocyst stage. It is by this adhesion, that the fetus receives oxygen and nutrients from the mother and is able to grow.
The female reproductive organ in which the embryo gets embedded is the uterus.

Write the location and function of the following in human testes:
(a) Sertoli cells (b) Leydig cells

(a) Sertoli cells are located within the seminiferous tubules of the testes.
Function: They provide nutrition to the developing sperms.

(b) The Leydig cells are located in the interstitial spaces between the seminiferous tubules.
Function: They synthesize and secrete androgen hormones (like testosterone).

Mention the difference between spermiogenesis and spermiation.

Spermiogenesis is the process of transformation of spermatids into spermatozoa. it is the final stage of spermatogenesis, which sees the maturation of spermatids into mature, motile spermatozoa.

Spermiation: The process of the release of spermatozoa from Sertoli cells into the cavity of seminiferous tubules.

(a) Draw a diagram of the structure of a human ovum surrounded by corona radiata. Label the following parts:
(i) Ovum (ii) Plasma Membrane (iii) Zona Pellucida
(b) State the function of Zona Pellucida.

a) The given diagram shows the labelled sketch of human ovum showing corona radiata.

b) Zona pellucida forms the protective layer of oocyte and embryo during development. It is responsible for regulation of interaction between ovulated egg and free floating sperm

Draw a labelled diagram of the sectional view of a human seminiferous tubule. (six parts to be labelled)

What is spermatogenesis? Briefly describe the process of spermatogenesis.

Explanation:

Spermatogenesis is the process of the production of sperms from the immature male germ cells. It starts at puberty and usually continues uninterrupted until death, although a slight decrease in the quantity of sperm is seen with the increase in age.

Process of Spermatogenesis:

The spermatogonia (2N) present at the inner side of the seminiferous tubules multiply by mitotic divisions and increase in number.
They stop undergoing mitosis, grow and become primary spermatocytes (2N). Each primary spermatocyte undergoes meiosis to form two equal haploid secondary spermatocytes (N).
Each secondary spermatocyte then undergoes a second meiotic division to form four equal haploid cells called spermatids (N).
Spermatids receive nourishment to form sperms by the process called spermiogenesis.

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Draw a labelled diagram of male reproductive system.

The given diagram represents the male reproductive system that regulates the formation and transportation of male gametes.

(a) Draw a labelled diagrammatic view of human male reproductive system.
(b) Differentiate between:
(i) Vas deferens and vasa efferentia
(ii) Spermatogenesis and spermiogenesis

a) The above given figure shows the diagram of the human male reproductive system.

b) i) Vas deferens is a tube-like structure which conducts the spermatozoa from the epididymis to the penis.
Vasa efferentia connects the rete testis to the epididymis.

(ii) Spermatogenesis is the process of production of sperms from immature germ cells in males. The number of cells is increased as each spermatogonium produces four spermatids. This makes a diploid cell, haploid.

Whereas spermiogenesis is the process of transformation of a circular spermatid to motile spermatozoa. There are no changes in the number of cells as only one spermatid develops into spermatozoa. There is no effect on the genetic material of the germ cells.

Draw a labelled diagram of sperm.

Describe the structure of a seminiferous tubule.

Each testicular lobule has tightly coiled seminiferous tubules which are packed with cells undergoing spermatogenesis (spermatogonia) and Sertoli cells. A germinal epithelium of delicate connective tissue surrounds the seminiferous tubules. The large sustentacular cells that extend from the capsule to the lumen of the seminiferous tubule are called Sertoli cells. They serve to support, nourish and regulate the development of cells undergoing spermatogenesis. The endocrine cells present in the space between seminiferous tubules are termed as interstitial cells of Leydig. They serve to secrete androgen, testosterone.

Name the hormones involved in regulation of spermatogenesis.

Gonadotropins FSH and LH are secreted by the anterior pituitary. FSH promotes spermatogenesis in the seminiferous tubules and LH promotes androgen production in the interstitial cells (androgens are required for attainment of reproductive maturity in males).

Define spermiogenesis and spermiation.

Transformation of spermatids into sperm by morphological changes without involving cell division is called as spermiogenesis. The release of mature spermatozoa from the Sertoli cells into the lumen of seminiferous tubules is called as spermiation.

What are the major components of seminal plasma?

Semen is a mixture of sperms and seminal plasma. Seminal vesicle secretion accounts for 60% of seminal plasma and adds alkaline pH (to counteract acidic pH of the vagina), fructose (a nutrient), mucus and coagulating and local acting enzymes. Prostate gland secretions account for 30% of plasma and add citrate (a nutrient for sperm mitochondria), calcium and a proteolytic enzyme termed as prostate specific antigen (to liquefy ejaculate just before release). Secretion from Cowper gland adds only small volume.

Draw a labelled diagram of a Graafian follicle.

Graafian follicle is a fluid-filled structure in the mammalian ovary which carries ovum development.

Identify True/False statements. Correct each false statement to make it true.
(a) Androgens are produced by Sertoli cells. (True/False)
(b) Spermatozoa get nutrition from Sertoli cells. (True/False)
(c) Leydig cells are found in ovary. (True/False)
(d) Leydig cells synthesise androgens. (True/False)
(e) Oogenesis takes place in corpus luteum. (True/False)
(f) Menstrual cycle ceases during pregnancy. (True/False)
(g) Presence or absence of hymen is not a reliable indicator of virginity or sexual experience. (True/False)

(a) Androgens are produced by Sertoli cells. (False) Androgens are produced by Leydig cells.

(b) Spermatozoa get nutrition from Sertoli cells. (True)

(d) Leydig cells synthesise androgens. (True)

(e) Oogenesis takes place in corpus luteum. (False) Oogenesis takes place in the ovary.

(f) Menstrual cycle ceases during pregnancy. (True)

(g) Presence or absence of the hymen is not a reliable indicator of virginity or sexual experience. (True)

Why do fish and frog produce a huge number of eggs each year?

The type of fertilization in fish and frog is external fertilization i.e fertilization takes place outside the body. In fish and frog fertilization takes place in water. As the chance of fertilization is nature dependant i.e it depends on the movement of water for the sperm to come in contact with the egg. Thus the fish and frog produce a huge number of eggs each year to overcome the chance factor(sperm to come in contact with egg) and produce offsprings.

What are the major functions of male accessory ducts and glands?

The male accessory ducts (vasa efferentia, epididymis, vas deferens, and rete testis) serve to store spermatozoa and to transport them outside urethra during ejaculation. Male accessory glands are seminal vesicles, prostate glands, and bulbourethral glands which contribute seminal plasma to semen. Seminal vesicle secretion accounts for 60% of seminal plasma and adds alkaline pH (to counteract acidic pH of the vagina), fructose (a nutrient), mucus and coagulating and local acting enzymes. Prostate gland secretions account for 30% of plasma and add citrate (a nutrient for sperm mitochondria), calcium and a proteolytic enzyme termed as prostate-specific antigen (to liquefy ejaculate just before release). Secretion from Cowper gland adds only small volume.

When an ovum gets fertilized, menstrual cycle stop temporarily in a woman. Give reason.

Menstrual cycle occurs due to rupture and shedding of the endometrium lining of the uterus. When an ovum gets fertilised the endometrium gets thickened, and vascularized to house the embryo. So during the whole term when the embryo/foetus is in the uterus, menstrual cycle stops temporarily.

Give the exact location of the prostate gland.

The prostate gland lies in the pelvic cavity in front of the rectum and behind the symphysis pubis, surrounding the first part of the urethra. It is present just inferior to the urinary bladder. It produces a large portion of the fluid which makes up the semen.

Find the odd one out and write it:
Vagina, Uterus, Vas deferens, Ovary.

Vas deferens is the male reproductive organ, whereas rest of the others are female reproductive organs. It is a thick-walled tube which transports sperm from the epididymis to the ejaculatory duct for ejaculation.

The uterus is present in female and it is the site of implantation.

The vagina is the copulation canal in the female.

The ovary is the reproductive organ which produces ovum. The ovum is fertilized by the sperm to form a zygote.

Give the biological technical term for complete stoppage of menstrual cycle in females.

Menopause is the cessation of menstrual cycle wherein ovaries do not respond to gonadotropic hormones produced by the anterior pituitary and do not secrete estrogens and progesterone.

Explain the process of spermatogenesis in humans.

The process of formation of sperms is called spermatogenesis. It occurs in the male gonads testis. Testes are made up of many seminiferous tubules lined by germinal epithelium. Cells of this layer divide to form spermatozoa in the following steps:

(1) Multiplication Phase: At maturity, the primordial germ cells divide by mitosis to produce a large number of spermatogonia. Type A spermatogonia is the stem cells which divide to form spermatogonia. Type B spermatogonia are the precursors of sperms.

(2) Growth Phase: Type B spermatogonium actively grows to a primary spermatocyte. It obtains nourishment from the nursing cells.

(3) Maturation Phase: Each primary spermatocyte undergoes two maturation divisions. The first maturation division is reductional and forms two haploid daughter cells called secondary spermatocytes. Both secondary spermatocytes then undergo second maturation division to form four haploid spermatids.

(4) Spermiogenesis: It is the process of transformation of spermatid to a spermatozoan. The spermatozoa are then known as sperms. The four spermatid becomes the head of the sperm, the Golgi apparatus, containing proteolytic enzymes, becomes the acrosome cap.

Explain the process of spermatogenesis in detail.

(2) Growth Phase: Type B spermatogonium actively grows to a primary spermatocyte. It obtains nourishment from the nursing cells.

(4) Spermiogenesis: It is the process of transformation of spermatic to a spermatozoan. The spermatozoa are then known as sperms. The four spermatid becomes the head of the sperm, the Golgi apparatus, containing proteolytic enzymes, becomes the acrosome cap.

What is compaction in the human development?

The morula (stage of embryonic development in humans) is referred to the ball of 16 cells which are formed from the repetitive cleavage of the zygote. During this stage, the differentiation starts among the cells. The outer cells begin to flatten out and the inner cells attach firmly to each other. This process is known as compaction where the tight junctions are formed between the cells.

Define:
1) Reparative regeneration 2) Capacitation 3) Menarche

(i) True regeneration or reparative regeneration occurs when a structure is removed by an external source and the body replaces the lost structure. The liver has the greatest regenerative capacity of any organ in the body.

(ii) Before fertilizing the ovum, the sperm prepares itself for the act of fertilization and undergoes many changes. These changes in a sperm just prior to fertilization are called capacitation.

(iii) It is the onset of menstruation in a young female at the age of about 12 to 13 years.

What is corpus luteum and what is its function?

Corpus luteum is the structure which is formed by the follicles after the egg is released from the Graafian follicle. This is a yellow coloured structure which is present in the ovary. The corpus luteum is the structure which is responsible for the release of the hormone progesterone. This is known as the pregnancy hormone which causes changes in the ovary and increasing the cell lining in the uterus. The hormone helps in maintaining pregnancy.

Name the cells that secrete androgens.

The Leydig cells in the testes secrete androgens which are paracrine in function and act on the Sertoli cells in the testes to produce the sperms.

Sketch the label 'human male reproductive system'.

Image result for male reproductive organ

The image represents the labelled diagram of the male reproductive system in humans.

Answer in one sentences:
What is Menarche?

Menarche is defined as the stage in a women's lifetime during which there is an onset of menstruation which occurs at about 12-13 years of age in the life cycle of the female.

Explain the phases of spermatogenesis in humans with the help of a diagram.

Spermatogenesis: Formation of sperms in testis is called as spermatogenesis. It involves the following steps:

(1) Multiplication phase: In this phase, the cells of generative layer divide and redivide to produce spermatogonia.

(2) Growth phase: In this phase, spermatogonia grows and then it is called as.spermatocytes.

(3) Maturation phase: In this phase metamorphosis occurs in the spermatids to produce a well-developed sperm which is divided into three parts:

(i) Head,

(ii) Neck

(iii) Tail.

Draw only ray-diagram of spermatogenesis.

This is a ray-diagram of spermatogenesis.

What is spermatogenesis? Explain with the help of diagram.

The formation of sperms in testis is called as spermatogenesis. It involves the following steps:
(1) Multiplication phase: In this phase, the cells of the generative layer known as germ cells divide and redivide through mitosis to produce spermatogonia.
(2) Growth phase: In this phase, spermatogonia grow in size, and now it is known as Primary spermatocytes.
(3) Maturation phase: In this phase primary spermatocyte divides by meiosis to produce four haploid spermatids.

(4) Spermiogenesis: In this phase, spermatids undergo metamorphosis to produce a well-developed sperm which is divided into three parts: (i) Head, (ii) Neck, and (iii) Tail.

Why testis are found outside the abdominal cavity in males?

One pair of the testis is found in man where sperms are formed. This testes found in the scrotal sac. Since the formation of sperms does not take place at the body temperature, but these forms at $$2-3^oC$$ below of the body temperature. Hence testes hang outside of the abdomen while in the embryonic stage this is found in the abdomen cavity.

Write only the name of different stages of human reproduction.

1. Gametogenesis:

It is the formation of haploid gametes called sperms and ova from diploid primary germ cells called gametogonia. This includes

(a) Spermatogenesis: Formation of haploid sperms in males.

(b) Oogenesis: Formation of haploid ova in females.

2. Insemination :

It is the release of seminal fluid of male in the vagina of the female.

3. Fertilization:

It is the fusion of haploid male and female gametes to form the diploid zygote.

4. Cleavage:

It is the mitotic division of zygote to form blastula.

5. Implantation:

It is the attachment of a blastocyst on the endometrium of the uterus.

6. Placentation:

It is the formation of a tissue called placenta between the fetus and mother for nutrition, respiration and excretion of the fetus.

7. Gastrulation:

It is the process by which blastocyst is changed into gastrula with three primary germ layers.

8. Organogenesis:

It is the formation of specific organ systems from three primary germ layers of the gastrula.

9. Parturition:

It is childbirth that makes the end of reproductive phase.

Write four differences between spermatogenesis and oogenesis.

Spermatogenesis

Oogenesis

1	. Polar bodies are not formed

Polar bodies are formed.

2.	There is an equal division.

There is unequal division.

3.	There is no yolk in sperms.

Eggs contain yolk.

4. A large number of sperm are found by this process.

Fewer numbers of ovum are formed by this process.

The study of physical abnormalities of embryo is called as

A congenital disorder is the abnormalities or defects that occur at the time of before birth. It comes from parents. Thus, the study of physical abnormalities of the embryo is called as a congenital disorder.

Observe the diagram, and answer the question:
(a) Identify A and B.
(b) What is the function of C?
(c) In which of the marked part reduction division takes place? What is the significance of it?

a) A is spermatid and B is the germinal cell

b) C is the primary spermatocyte that undergoes meiosis 1 to form a secondary spermatocyte.

c) Reduction division takes place in primary spermatocyte (C).

Primary spermatocyte undergoes meiosis 1 to form secondary spermatocyte. Secondary spermatocyte undergoes meiosis 2 to form spermatids that mature into sperm cells.

The following graph shows the levels of pituitary hormones during a menstrual cycle. What do 1 and 2 represent?

Graph 1 represents the level of FSH hormone (Follicle Stimulating Hormone) and graph 2 represents level of LH hormone (Luteinizing Hormone) during menstrual cycle. The menstrual cycle is divided into follicular or proliferative phase, and the luteal or secretory phase. LH and FSH are the hormones that encourage ovulation. Both LH and FSH are secreted by the pituitary gland in the brain. At the beginning of the cycle, LH and FSH levels usually less in range. Both LH along with FSH peaks on the 14th day.

Mention the exact location of the following:
Prostate gland.

Prostate gland is present at the base of the urinary bladder and in front of the rectum. It surrounds the urethra.

The diagram shown below is the longitudinal section of a testis of man. Study it carefully and answer the questions that follow:
State the functions of the parts labelled $$1$$ and $$3$$ in the diagram.

1. Scrotum: It provides lower temperature than outside temperature which is required for the sperm to produce and survive.

2. Vas deferens: It carries sperm from epididymis to urethra.

3. Epididymis: Here, sperms mature and are stored.

Given appropriate biological/ technical terms for the following:
The accessory gland in human males whose secretion activates the sperms.

Prostate gland is the accessory gland in human males whose secretion activates the sperms.

The diagram shown below is the longitudinal section of the testis of man. Study it carefully and answer the following questions.

a. Label the parts numbered $$1$$ to $$3$$ in the diagram.
b. In which part of the testis sperms are produced?

a. 1. Scrotum, 2. Vas deference and 3. Epididymis.

b. Sperms are produced in the seminiferous tubules.

The diagram shown below is the longitudinal section of a testis of man. Study it carefully and answer the questions that follow:
In which part of the testis are the sperms produced?

Sperms are produced in the seminiferous tubules.

Define spermiogenesis.

Spermiogenesis is the final stage of spermatogenesis. It is the maturation of spermatids into mature, motile spermatozoa. The spermatid at this stage contains nucleus, Golgi apparatus, centriole and mitochondria.

Mention the exact location of the following:
a. Epididymis
b. Lacrimal gland
c. Malleus
d. Hydathodes
e. Pulmonary semilunar valve

a. Epididymis is a tube that connects a testicle to a vas deferens in the male reproductive system. It is located inside the scrotum and posterior to the testis.

b. Lacrimal gland is located within the orbit above the lateral end of the eye in the lacrimal fossa of the orbit. It secretes aqueous layer which cleanses and protects the surface of eye.

c. Malleus is also called as hammer. It is present in the middle ear. It is located between the tympanic membrane and the incus. It is attached to the inner surface of the eardrum.

d. Hydathodes are found at the leaves margins of angiosperms, aquatic plants and herbaceous plants growing in moist weather. They secrete water through pores in the epidermis.

e. Pulmonary semilunar valve is located between the right ventricle and the pulmonary artery and has three cusps. It prevents back flow of blood into the right ventricle.

Draw a labelled diagram of L.S. of human testis.

Give appropriate biological or technical terms for the following.
The onset of menstruation in a young girl.

The onset of menstruation in a young girl is called menarche. It is the release of first menstrual flow or period and marks the beginning of a female's reproductive life.

Choose the ODD one out from the following terms given and name the CATEGORY to which the others belong.
Example: Nose, Tongue, Arm, Eye
Answer: Odd Term- Arm, Category- Sense organs
Prostate gland, Cowper's gland, seminal vesicle, seminiferous tubules.

Odd Term- Seminiferous tubule Category- Male reproductive system glands

Define the following term:
Implantation

In humans, implantation is the stage of pregnancy at which the embryo adheres to the wall of the uterus. At this stage of prenatal development, the conceptus is called a blastocyst. It is by this adhesion that the embryo receives oxygen and nutrients from the mother to be able to grow.

Describe the histology of human testis. Write a note on human sperm.

Histology of testes:

The testis is surrounded by three protective layers which are known as tunicae. These three layers are Tunica vaginalis, Tunica albuginea, and Tunica vasculosa. Each testis contains about 250 compartments called testicular lobule and each lobule contains one to three highly coiled seminiferous tubules where sperms are produced. The stratified epithelium of seminiferous tubules is made up of two type of cells- Sertoli cells and Spermatogenic cells or male germ cells.

Sertoli cells are elongated and pyramidal which partially envelope the spermatogenic cells and nourish the spermatozoa. Spermatogenic cells are stacked in 4-8 layers that occupy the space between the basal lamina and the lumen of the tubule. These cells divide several times and differentiate to form spermatozoa.

Between the seminiferous tubules are present the Leydig cells. These cells secrete testosterone hormone that controls spermatogenesis.

Short note on Human Sperm:

A mature human sperm cell is a microscopic and tadpole-shaped cell. It consists of an oval head, a cylindrical body having neck and body piece and an elongated tail.

Head contains the nucleus which has a haploid number of chromosomes i.e. 23 in human and an acrosome which contains hydrolytic enzymes called sperm lysin e.g. hyaluronidase. The acrosome is involved in the penetration of the layers of sperm cells surrounding the egg immediately before fertilization.

The short neck consists of a pair of centrioles at a right angle to each other. The middle piece is enlarged by the presence of many mitochondria. Mitochondria carry out aerobic respiration and produce ATP which helps in the movement of sperm.

The tail is several times longer than the head and contains cytoplasm. It has two parts- main piece and end piece. The main piece has a covering of cytoplasm and the end piece consists of a naked filament but lacks cytoplasm.

State the functions of the following:
Seminal vesicles

Seminal vesicles release up to 60% of the fluid found in semen. The other 40% is produced by the prostate and bulbourethral glands. The fluid produced by seminal vesicles will contain several key components: Fructose: which is a sugar that is produced to provide energy for swimming sperm cells.

Why is it important that a very large number of sperms should be present in the semen?

Sperms are produced in large numbers to ensure the fertilisation of the ovum. In the female reproductive tract as sperms swim up to meet the ovum, there are various obstructions that lead up to fertilisation: Some sperms die due to vaginal secretions, or due to their short life span. Some sperms die in the uterus, and some cannot swim in the fallopian tube and later die. Only a few of them reach the ovum, but only one if successful in fertilising the ovum.

Very short answer type.
Give the scientific term for the animals which gave birth to young ones.

Viviparous

Application Based Questions :
Lack of menstruation is an indication of pregnancy.

Lack of menstruation may be indicative of pregnancy. However, it may also be caused due to some other underlying causes like stress, poor health, etc.

Differentiate between :
Menarche and menopause

Menarche is the first menstruation of the human female on the attainment of puberty that occurs at about 13 years of age, whereas menopause is the phase in the human females life when ovulation and menstruation stop that occurs at about 45-55 years of age.

Give basic difference between spermatogenesis and oogenesis.

Oogenesis is fundamentally similar to spermatogenesis with regard to the behaviour of chromosomes. But there are important differences between oogenesis and spermatogenesis.

(i) one primary spermatocyte gives rise to four spermatozoa, but one primary oocyte forms only a single ovum.

(ii) when the primary spermatocyte divides, its cytoplasm is equally distributed between the two secondary spermatocytes formed, but during the division of the primary oocyte, almost all its cytoplasm goes to the daughter cell which forms the secondary oocyte. The other daughter cell (first polar body) though receives half the chromosomes of the primary oocyte, it does not receive any cytoplasm.

Very short answer type.
Mention the most significant function/role of acrosome:

Secretes hyaluronidase enzyme that helps in the removal of follicle cells from the ovum to facilitate the entry of the spermatozoon into the ovum.

Short / Long Answer question Type :
Write short notes on Menarche

The first menstruation begins at puberty when the girl or woman is around 10 to 12 years of age. The first occurrence of menstruation at puberty is called menarche. Menarche is the beginning of the reproductive life of a girl. In other words, menarche is the time from which a girl or woman becomes capable of conception.

Very short answer type.
When and where does spermatogenesis occur in .a human male?

Occurs in the male gonads (testis); it starts at the age of puberty and continues even ii, old age.

Very short answer type.
Define the term spermiogenesis

Spermiogenesis is the final stage of spermatogenesis. It is responsible for the maturation of spermatids into mature, motile spermatozoa.

Application Based Questions :
In humans, the testes are situated outside the abdominal cavity. Why?

In humans, the testes are situated outside the abdominal cavity within a pouch called scrotum. The scrotum helps in maintaining the low temperature of the testes $$(2^{\circ} \, - \, 25^{\circ}C)$$ lower than the normal internal body temperature) necessary for spermatogenesis.

Very short answer type.
What is the proliferative phase in the menstrual cycle? For how many days does it last?

After menstruation, the growth and proliferation of tissues on the walls of the uterus, fallopian tubes and vagina; it lasts for 10-12 days and at its end the ovum is ejected (ovulation) from the Graafian follicle of the ovary.

Differentiate between :
Vas deferens and vasa efferentia

Vasa efferentia arise from the rete testis and open into the epididymis and conduct spermatozoa out from the testis, whereas vas deferens is a partially coiled thick muscular tube arising from each epididymis. This tube conducts spermatozoa from the epididymis to the base of the urinary bladder.

Fill in the blanks:
Zygote is ______ (diploid/haploid)

Male and female gametes are haploid carrying the equal number of chromosomes. They are fused to form a diploid embryo by the process called fertilisation.

What is implantation?

On the sixth day following fertilisation, the blastocyst attaches to the uterine wall, with the side containing the inner cell mass positioned against the endometrium. The trophoblast cells produce enzymes that allows the blastocysts to 'eat its way' into thick endometrium. This begins the process of implantation and it leads to pregnancy.

Name the functions of Endometrium.

Endometrium is the inner wall of the uterus. it undergoes various cyclic changes during menstrual cycle. It first thickens for implantation of embryo, but if fertilization does not take place, if sheds off, leading to fall of menstrual blood. If the fertilization takes place, then it implants the zygote and nourishes it.

Humans are ______ as they undergo internal fertilization to give birth to newborns.

Humans are viviparous animals.
Like most mammals, they undergo internal fertilization to give birth to newborns.
The zygote formation or the fertilization of the egg cell takes place inside the mother's body.

What is Periodic abstinence?

Periodic abstinence is a type of natural contraception. In this type, the couples do not engage in sexual intercourse from day 10 to day 17 of the menstrual cycle. This is because ovulation is expected on these days and chances of getting pregnant are high.

Enumerate the events in the ovary of a human female during follicular phase of menstrual cycle.

This phase also begins on the first day of menstruation, but it lasts till the 13th day of the menstrual cycle. The following events occur during this phase:

• The pituitary gland secretes a hormone that stimulates the egg cells in the ovaries to grow.

• One of these egg cells begins to mature in a sac-like-structure called follicle. It takes 13 days for the egg cell to reach maturity.

• While the egg cell matures, its follicle secretes a hormone that stimulates the uterus to develop a lining of blood vessels and soft tissue called endometrium.

What is menstrual cycle? Which hormones regulate menstrual cycle?

Explanation:

The reproductive cycle that occurs in female primates is called menstrual cycle.
In human females, sexual cycle begins when a girl attains puberty.
Menstruation is repeats at an interval of about 28 or 29 days.
In the middle of each cycle, one ovum is released from either of the two ovaries.
Ovarian hormones, such as, estrogen and progesterone, and gonadotropic hormones, such as, LH (luteinizing hormone) and FSH (follicle stimulating hormone) regulate menstrual cycle.

Explain the steps in the formation of an ovum from an oogonium in humans.

Oogenesis is initiated in embryonic ovaries of the female fetus.
The cell starts division (oogonia) and enter into prophase 1 of the meiotic cycle and get temporarily arrested at that stage, called primary oocyte.
Each primary oocyte gets surrounded by a layer of granulosa cell and then called primary follicle. Many of these degenerate, hence by puberty only 60000 - 80000 primary follicle remain.
Further, it gets surrounded by more layers of granulosa and a new theca and form secondary follicle.
Soon these transform into the tertiary follicle, characterized by the presence of fluid-filled cavity called Antrum. At this stage, the primary oocyte grows and completes it's first meiotic division.
The division is unequal and leads to the formation of a large secondary oocyte and a tiny polar body.
The tertiary follicle further mature into Graafian follicle, the secondary oocyte forms a new layer called Zona pellucida surrounding itself.
During ovulation, this follicle ruptures to release secondary oocyte/ovum (which completes 2nd meiotic division just prior to fertilization)

Mention the function of trophoblast in human embryo.

Trophoblast is cells forming the outer layer of a blastocyst, which provide nutrients to the embryo and develop into a large part of the placenta. They are formed during the first stage of pregnancy and are the first cells to differentiate from the fertilized egg.

Give a schematic representation of spermatogenesis in humans.

Spermatogenesis is the process of the production of sperms from the immature germ cells in males. It takes place in seminiferous tubules present inside the testes. During spermatogenesis, a diploid spermatogonium (male germ cell) increases its size to form a diploid primary spermatocyte. This diploid primary spermatocyte undergoes first meiotic division (meiosis I), which is a reductional division to form two equal haploid secondary spermatocytes. Each secondary spermatocyte then undergoes second meiotic division (meiosis II) to form two equal haploid spermatids. Hence, a diploid spermatogonium produces four haploid spermatids. These spermatids are transformed into spermatozoa (sperm) by the process called spermiogenesis
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When and how does placenta develop in human female?

The placenta is an organ found in the mammals only during the development of the foetus. After around 12 weeks of pregnancy, the chorionic villi and uterine tissue become interdigitated with each other and together form a structural and functional unit between developing embryo (foetus) and maternal body called placenta. A tough cord called umbilical cord is also formed during this time which connects the embryo to the uterus through the placenta. Placenta provides nutrients to the embryo.

Draw a labelled diagram of a sectional view of human seminiferous tubule.

Given is the detailed section of a testis and the seminiferous tubules of the human male.
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Enumerate the events in the ovary of a human female during Luteal phase of menstrual cycle.

This phase begins on the 15th day and lasts till the end of the cycle. The following events occur during this phase:

• The egg cell released during the ovulation phase stays in the fallopian tube for 24 hours.

• If a sperm cell does not impregnate the egg cell within that time, the egg cell disintegrates.

• The hormone that causes the uterus to retain its endometrium gets used up by the end of the menstrual cycle. This causes the menstrual phase of the next cycle to begin.

Explain the hormonal regulation of the process of spermatogenesis in humans.

In humans the mechanism is not completely understood; however, it is known that the initiation of spermatogenesis occurs at puberty due to the interaction of the hypothalamus, pituitary gland, and Leydig cells. If the pituitary gland is removed, spermatogenesis can still be initiated by follicle stimulating hormone (FSH) and testosterone.
FSH stimulates both the production of androgen-binding protein (ABP) by Sertoli cells and the formation of the blood-testis barrier. ABP is essential to concentrating testosterone in levels high enough to initiate and maintain spermatogenesis.
Intratesticular testosterone levels are 20–100 or 50–200 times higher than the concentration found in blood, although there is variation over a 5- to 10-fold range amongst healthy men.

Draw a diagrammatic sectional view of a human seminiferous tubule, and label Sertoli cells, primary spermatocyte, spermatogonium and spermatozoa in it.

Image result for human seminiferous tubule

What is Menstrual cycle? Describe it in brief.

Explanation:

Female reproductive system undergoes some natural changes after attaining puberty and those changes repeated at the interval of every 28 – 30 days. These cyclic changes are called as menstrual cycle.

Menstrual cycle is a natural process or cycle, which is controlled by 4 hormones. These 4 hormones are follicle stimulating hormone (FSH), luteinizing hormone (LH), estrogen and progesterone.

One of the several follicles in the ovary begins to develop along with the oocyte present in it, under the effect of follicle stimulating hormone (FSH). This developing follicle secretes estrogen.

Endometrium of the uterus begins to develop during first cycle or regenerates during subsequent cycles under the effect of estrogen.

As developing follicle completes its development. Afterward it ruptures under the effect of luteinizing hormone and oocyte is released. This is known as ovulation.

Left tissues of the burst follicle forms the corpus luteum. After that Corpus luteum starts to secrete progesterone.

Then Endometrial glands secrete their secretion under the influence of progesterone.

Such endometrium is ready for implantation of embryo.

Which cell organelles are found in the formation of middle part of sperm?

A sperm has three main parts:

1) The head of the sperm contains the nucleus. The nucleus holds the DNA of the cell. The head also contains enzymes that help the sperm break through the cell membrane of an egg.

2) The midpiece of the sperm is packed with mitochondria. Mitochondria are organelles in cells that produce energy. Sperm use the energy in the midpiece to move.

3) The tail of the sperm moves like a propeller, around and around. This tail is a long flagella that pushes the sperm forward. A sperm can travel about 30 inches per hour.

Describe the functions of seminal vesicles.

Seminal vesicles are a pair of simple tubular glands that are located posterior-inferior to the urinary bladder of males. They are also called seminal glands. Their secretion is a constituent of the semen produced by the males. Around 70-75% of the semen is composed of secretions of the seminal vesicles which includes proteins, enzymes, fructose, mucus, vitamin C, flavins, phosphorylcholine, and prostaglandins. Their excretory ducts open into the vas deferens. Their structure and function are mainly controlled by androgens.

Write a brief note on hormonal regulation of spermatogenesis.

In human male reproductive system, The onset of puberty, hypothalamus begins secreting high pulses of GnRH, or gonadotropin-releasing hormone. In response, the pituitary gland releases follicle stimulating hormone (FSH) and luteinizing hormone (LH) into the male system for the first time. FSH enters the testes, stimulating the sertoli cells, which help to nourish the sperm cells that the testes produce, to begin facilitating spermatogenesis. LH also enters the testes, stimulating the interstitial cells, called leydig cells, to make and release testosterone into the testes and the blood.

Testosterone, the hormone responsible for the secondary sexual characteristics that develop in the male during adolescence, stimulates spermatogenesis.

When rising levels of testosterone act on the hypothalamus and anterior pituitary to inhibit the release of GnRH, FSH, and LH. The sertoli cells produce the hormone inhibin, which is released into the blood when the sperm count is too high.

Rewrite the terms in the correct order so as to be in a logical sequence.
Puberty, menopause, menstruals, menarche, reproductive age.

Reproductive age, Puberty, Menarche, Menstruals, Menopause.

Reproductive age - Technically, women can get pregnant and bear children from puberty when they start getting their menstrual period to menopause when they stop getting it. The average woman's reproductive years are between ages 12 and 51.

Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy.

Menarche is the first menstrual cycle, or first menstrual bleeding, in female humans. From both social and medical perspectives, it is often considered the central event of female puberty, as it signals the possibility of fertility. Girls experience menarche at different ages.

The menstrual cycle is the regular natural change that occurs in the female reproductive system that makes pregnancy possible. The cycle is required for the production of oocytes, and for the preparation of the uterus for pregnancy.

Menopause is the process through which a woman ceases to be fertile or menstruate. It is a normal part of life and is not considered a disease or a condition. Symptoms may occur years before a woman's final period. Some women may experience symptoms for months or years afterward.

Differentiate oviparous and viviparous organisms. Also, give examples.

Oviparous Animals	Viviparous Animals
1. Oviparous animals lay fertilized or unfertilized eggs.	1. Viviparous animals give birth to young ones.
2. The fertilized eggs remain covered by hard calcareous shell and laid in safe place in the environment.	2. The fertilised egg (zygote) develop into a young one inside the body of the female organism.
3. Chances of survival of young ones is less as the female lay egg in the open environment.	3. Chances of survival of young one is more because of proper embryonic care and protection inside the mother’s body.
4. Example : Birds, Reptiles, Amphibian, Pisces, Insects etc.	4. Example : Most of the mammals.

Name the fluid surrounding the developing embryo.

The developing embryo is surrounded by the amniotic fluid. This amniotic fluid contains vital nutrients, hormones, and antibodies against various infections.

Give appropriate terms for the fixing of developing zygote (blastocyst) on the uterine wall.

Implantation is a process in which a developing embryo, moving as a blastocyst through a uterus, makes contact with the uterine wall and remains attached to it until birth. The lining of the uterus (endometrium) prepares for the developing blastocyst to attach to it via many internal changes. Without these changes, implantation will not occur, and the embryo sloughs off during menstruation. Such implantation is unique to mammals, but not all mammals exhibit it. Furthermore, of those mammals that exhibit implantation, the process differs in many respects between those mammals in which the females have estrous cycles and those mammals in which the females have menstrual cycles. Females in the different species of primates, including humans, have menstrual cycles, and thus similar processes of implantation.

Name the part where the where the sperms are produced in the testes.

The testes are oval organs about the size of very large olives that lie in the scrotum, secured at either end by a structure called the spermatic cord. Most men have two testes. The testes are responsible for making testosterone, the primary male sex hormone, and for producing sperm. Within the testes are coiled masses of tubes called seminiferous tubules. These tubules are responsible for producing the sperm cells through a process called spermatogenesis.

Name the tubular knot fitting like a cup on the upper side of the testis.

The epididymis is a tube that connects a testicle to a vas deferens in the male reproductive system. It is present in all male reptiles, birds, and mammals. It is a single, narrow, tightly-coiled tube in adult humans, 6 to 7 meters in length connecting the efferent ducts from the rear of each testicle to its vas deferens.

Spermatozoa formed in the testis enter the caput epididymis, progress to the corpus, and finally reach the cauda region, where they are stored. Sperm entering the caput epididymis are incomplete—they lack the ability to swim forward (motility) and to fertilize an egg. Epididymal transit takes 2-3 days in humans (longer in other species), but the sperm can be stored in the cauda for 2–3 days. During their transit in the epididymis, sperm undergoes maturation processes necessary for them to acquire motility and fertility. Final maturation (capacitation) is completed in the female reproductive tract.

Give appropriate terms for the onset of reproduction phase in a female.

The first menses or the first menstrual bleeding in a female human is called menarche. This marks the beginning of the reproductive or fertile phase of a female’s life.

Name the accessory gland in human males whose secretion activates the sperms.

The seminal vesicles, vesicular glands, or seminal glands, are a pair of simple tubular glands posteroinferior to the urinary bladder of some male mammals. Seminal vesicles are located within the pelvis. They secrete the fluid that partly composes the semen.

The seminal vesicles secrete a significant proportion of the fluid that ultimately becomes semen. Lipofuscin granules from dead epithelial cells give the secretion its yellowish color. About 70-85% of the seminal fluid in humans originates from the seminal vesicles but is not expelled in the first ejaculate fractions which are dominated by spermatozoa and zinc-rich prostatic fluid. The excretory duct of each seminal gland opens into the corresponding vas deferens as it enters the prostate gland. Seminal vesicle fluid is alkaline, resulting in human semen having a mildly alkaline pH.

Why more spermatozoa are formed as compared to ova?

Sperms are produced in large numbers because of low survival chance. They are quite sensitive to environmental factors such as pH and heat. The sperms once in the female vaginal orifice, have to move all the way up to the tube and only a few make it to that point. Therefore to increase the chances of a sperm reaching the ovum in the fallopian tube to fertilize it, they must be produced and released in large numbers.

What is implantation ? When does this process begin?

On the sixth day following fertilisation, the blastocyst gets attached to the wall of uterus in such a way that the side of inner cell mass is positioned against the endometrium. The trophoblast cells produce some enzymes that help the embryo to 'eat its way' into the thick endometrium. This begins the process of implantation. By the seventh to tenth day following implantation, the blastocyst is completely embedded or implanted in the endometrium.

Explain with a neat labelled diagram the T.S. of mammalian testis.

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What is menopause and menarche?

Menopause can be defined as the post-reproductive phase in human females when the primary oocytes have been exhausted and it marks the stop of the menstrual cycle. It generally occurs at the age of 45 years. Right after the menopause, the females cannot reproduce.

Menarche can be defined as the reproductive event when the females attain the puberty and the menstrual cycle begins. The active ovulation occurs and females are capable of reproduction. It starts from the age of 11 years.

Write note on : Implantation

In humans, implantation is that this stage of pregnancy at which the embryo adheres to the walls of the uterus.
At this stage of prenatal development, the conceptus is called a blastocyst.
It is by this adhesion that the embryo receives oxygen and nutrients from the murder to be able to grow.
Chorionic villi + uterine tissue (endometrium)= Placenta (Structural and functional unit between developing embryo and maternal body).

Differentiate between male and female gametes.

MALE GAMETES:

1)A male gamete is the male reproductive cell, which unites with the female gamete to produce the zygote.

2)Produced by spermatogenesis.

3)Produced in testes.

4)Smaller than female gametes.

5)Swims using tails.

6)Uses sugar in seminal fluid.

FEMALE GAMETES:

1)A female gamete is the female reproductive cell, which unites with male gamete to form the zygote.

2)Produced by oogenesis.

3)Produced in the ovaries.

4)Larger than male gametes.

5)Does not move by itself.

6)Uses protein and fat in the cytoplasm.

Write note on : Spermatogenesis

In testis, immaure male germ cell produce sperms by spermatogenesis.
The spermatogonia present in the inside wall of seminiferous tubule multiply by mitotic division.
Some spermatogonium called primary spermatocyte undergo meiosis,
A primary spermatocyte completes first meiotic division to give rise to the secondary spermatocyte.
After undergoing second meiotic division, spermatids are produced.
By spermiogenesis, these spermatids form Spermatozoa.

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What is menstrual cycle? When does it begins? What happens during this period?

Menstrual cycle is a regular naturally occurring changes within the body of females which prepares for pregnancy each month.
Girls start to have a menstrual cycle with the onset of puberty.
The four phases of the menstrual cycle are:-

1) Menstruation is the removal of the thickened lining of the uterus from the body through the vagina.

Menstrual fluid contains blood, cells from the lining of the uterus and mucus.
The average length of a period is three days to 7 days.

2) Follicular phase starts with the first day of menstruation and ends with ovulation.

The follicle stimulating hormone (FSH) released by pituitary gland stimulates the ovary to produce around five to 20 follicles.
Only one follicle will mature into an egg, while the others die.
This can occur around day 10 of a 28-day cycle.
During this period the growth of the follicles stimulates the lining of the uterus to thicken in preparation for possible pregnancy.

3) Ovulation is the release of a mature egg from the ovary.

This usually occurs mid-cycle, around 14th day of the cycle.
The lifespan of the typical egg is only around 24 hours.

4) Leutal phase in which the ruptured follicle transforms into a structure known as the corpus luteum.

This releases progesterone, along with small amounts of oestrogen.
This helps to maintain the thickened lining of the uterus for implantation of the embryo.
If implantation does not occur the corpus luteum dies around 22th- 28th day of the cycle.
The progesterone levels decreases which cause the lining of the uterus to fall away.
This is known as menstruation and the cycle repeats.

Is there an age limit to male fertility?

With the age the quality of sperms also declines i.e., men below 40 have better chance of fathering a child than those older than 40. Most men makes millions of new sperms everyday but men with ageing decreases the percentage of healthy sperms than younger men.

Label the parts A to D of the diagram.

A - Vas deferens

B - Tunica albuginea

C - Seminiferous tubules

D - Epididymis(Caput)

Define fertilisation and implantation?

Fertilisation:-

Fusion of gametes to initiate the development of new individual organism.

Implantation:-

The insertion of an organ or tissue in a new site in the body. In human,it is the stage of pregnancy at which the embryo adheres to the wall of the uterus.

Give one significant difference between spermatogenesis and oogenesis.

Spermatogenesis is the formation of a male gamete called sperm whereas oogenesis is the formation of a female gamete called ovum.

What are oviparous and viviparous animals?

- Animals show different methods of production of young ones. Oviparous and viviparous are such two methods.
- Oviparous animals do not undergo any embryonic development inside the mother whereas viviparous animals develop into a young animal inside the mother.
- This means oviparous animals lay eggs. These eggs develop and hatch into young individuals. In contrast, viviparous animals are born as live young individuals.
- Animals such as human beings, cows, dogs etc which give birth to young ones are viviparous animals.
- Animals such as hen, frog, lizards etc are oviparous animals.

Give functions of :
(a) Epididymis
(b) Seminiferous tubule

Function are as followed:

• Epididymis- Epididymis is a cooked tube. Sperms take several days to pass through this tube. These tubes produce essential chemicals for the maturation of sperms. Sperms achieve maturity and motility in the epididymis.

• Seminiferous tubules- Spermatogenesis, the process of producing spermatozoa takes place in the seminiferous tubules.

Give one significant difference between puberty and menarche.

Puberty is the period when adolescents reach sexual maturity and become capable of reproduction whereas the first occurrence of menstruation is known as menarche.

Ovulation takes place on the $$14^{th}$$ day of menstrual cycle. Why?

Ovulation is when an egg is released from the ovary in females. LH rise elevate the estrogen release from the growing follicle and it is this rise that triggers the events that trigger ovulation to take place on 14th day of menstrual cycle. LH make the egg inside the follicle become fully mature and ready for release and fertilisation.

Name an animal that stays in water like fish but has no gills to breathe in water. It gives birth to babies like the tiger does, but does not live in the forest.

$$\textbf{Solution:}$$

$$\bullet$$ Whales are aquatic mammals that breathe air with the help of the lungs.

$$\bullet$$ Whales do not possess any gills, like other aquatic organisms.

$$\bullet$$ They give birth to young ones directly like the other mammals. This is why it is called a viviparous organism.

$$\bullet$$ It does not live in forests like tigers as whales live in aquatic habitats.

$$\bullet$$ All the characteristics of mammals make whales the largest living aquatic mammal in the world.

What is Zygote?

Explanation:

The parent organism produces a haploid sex gamete called sperm in males and ova or ovum in females.
When these haploid gametes fuse, It brings out fertilization and forms a diploid zygote, which further undergoes division to become an organism.

The zygote: first stage of embryo development after fertilization

The diagram given alongside is that of a developing human foetus in the womb. Study the same and answer the following question.
How many days does the foetus take to be fully developed?

The foetus takes about 280 days to be fully developed.

Mr. X is diagnosed for failure of spermiogenesis. Give a brief account on spermiogenesis.

Spermiogenesis is the process of development of mature spermatozoa from spermatids. During this process the head formation occurs, acrosome and tail formation also occurs, and the DNA gets packaged within basic proteins called protamines. This results in the formation of mature sperm cells. The failure in spermiogenesis will result in low sperm number, abnormal sperm morphology and low sperm motility.

Write about Zygote.

A zygote is formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete and contains all of the genetic information necessary to form a new individual. In multicellular organisms, the zygote is the earliest developmental stage. In humans and other animals, the zygote stage is brief and is followed by cleavage. During cleavage, the single cell becomes subdivided into smaller cells which subsequently develop into an embryo.

Draw the diagram showing the germination of pollen on stigma and label the following parts (i) stigma (ii) pollen tube

diagram is shown
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How do the characteristics of mother and father get transmitted in a human embryo?

Through sexual reproduction, the offspring cells or organisms acquire the genetic information of their parents. During fertilization, the male and the female gametes fuse to form the zygote, that later develops to form the embryo. The gametes posses a haploid genome of either parent and during fusion these characters present in the genome pass on to the offsprings. There are 22 chromosomes pairs (autosomes) and a pair of sex chromosomes (allosomes). If one of the sex chromosomes is a short Y chromosome, the baby will be male and if both are X chromosomes, the baby will be female.

Why there is pain when a woman is in a periods?

It is the endometrium wall of the uterus of the women that break off during period or menstruation. Due to the shedding off of endometrium wall along with blood cause pain when a woman is in a period.

Where are sperms stored and ejaculated from ?

Sperms are stored in the epididymis

Ejaculation takes place in two phases: in the first, or emission, stage, sperm are moved from the testes and the epididymis (where the sperm are stored) to the beginning of the urethra, a hollow tube running through the penis that transports either sperm or urine; in the second stage, ejaculation proper, the semen is moved through the urethra and expelled from the body.

Where Barr body is found?

Barr bodies are found in genotypically human female. One barr body is found per somatic cell. It is the kind of deactivated X chromosomes is seen as small dark staining structure in Nucleus. Barr body is found in male only in case of Klinefelter syndrome.

What is endometrium and what happens to it during the menstural cycle

The endometrium is the inner lining of the uterus, It is highly vascularised. It has a basal layer and a functional layer which becomes thick and shed during menstruation. During the first part of the cycle, estrogen is made by ovaries. It causes the lining to growth and thickening of the endometrium to prepare the uterus for pregnancy. If the fertilization doesn't occur then the decreased level of progesterone and estrogen results in menstruation. Once the lining is shed, a new menstrual cycle begins.
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Which part of the sperm head part comes in contact with the egg at the time of fertilization?

Solution:

The head of sperm consists of mitochondria, DNA and acrosomal proteins. The proteins are stored in the cap at the front of the sperm known as acrosome - this the part first contacts the egg. The enzyme present in the acrosome begin to digest zona pellucida in the egg cell and allow sperm to move inside the egg cell involves fertilization process.

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The onset of menstruation is termed as
Loss of reproductive capacity in women after age of 45-50 years, is termed as___.

Menarche: Menarche is the medical term for a woman's first menstruation, commonly known as her first period. Menstruation is the monthly shedding of the uterine wall. It typically occurs when girls are between the age of 9 and 15 years old. For the first several years, menstrual bleeding may be inconsistent and irregular. Girls in their early teens are likely to have irregular menstrual cycles, resulting in irregular ovulation.
Menopause; It is a stage of a woman's life characterized by the end of her menstrual cycle, and it marks the end of her child-bearing years. As a result of these biological changes, women often experience a number of different symptoms for a period of time, though they eventually subside.

Draw the structure of human male reproductive system.

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The cells of the testes that produce male hormones are known as __________

Testosterone is the hormone that is secreted by the cells in the vicinity of the seminiferous tubules.They are known as Leydig cells.

How much chromosomes do the drones of honeybees have? Name the type of cell division that occurs during the formation of spermatozoa in them.

The drones of honey bees are haploid in ploidy so they have 16 chromosomes. Now as they are haploid so to produce spermatozoa mitotic cell division is used (i.e. mitosis)

Explain the terms

a) Implantation
b) Placenta

(a) Implantation: The embryo enters the uterus at the stage of the blastocyst and becomes attached to the wall of the uterus, where it is to perform its subsequent development. This attachment of the blastocyst to the uterine wall is known as implantation.

(b) Placenta: It is a temporary organ built up of maternal and foetal tissues jointly. It serves for the transport of nutrients from the tissues of the mother with those of the embryo as well as the exchange of gases between the tissues of the two.

Explain the terms :

(a) Implantation
(b) Placenta

(a) Implantation: During the blastocyst stage, when the embryo enters the uterus, it becomes attached to the uterine wall and performs its subsequent development. This attachment of the blastocyst to the uterine wall is known as implantation.

(b) Placenta: It is a temporary organ made up of maternal and fetal tissues jointly during pregnancy. It serves for the transport of nutrients from the mother to the baby and also helps in the exchange of gases between the two.

Differentiate between menarche and menopause.

Menarche	Menopause
1. Menarche is the first beginning of menstrual cycle in females.	1. Menopause is the Cessation of menstrual cycle in females.
2. It starts at the age of 10-16 years.	2. It Ceases at the age of 45-50 years.
3. This is the start of reproductive maturity in females and gives them the ability to conceive.	3. This is the end of reproductive maturity, where females cannot conceive further.

Define ''Spermiation '' and ''Spermiogenesis''.

1) SPERMIATION: Spermiation is the process by which mature spermatids are released from Sertoli cells into the seminiferous tubule lumen prior to their passage to the epididymis.

2) SPERMIOGENESIS: Spermiogenesis is the final stage of spermatogenesis, which sees the maturation of spermatids into mature, motile spermatozoa.

Explain the female reproductive organ with diagram.

The outer part of the female reproductive organs is called the vulva, meaning coverage. The vulva is located between the legs and includes the opening inside the body to the vagina and other reproductive organs.
The pubis is called the fleshy region just above the top of the vaginal opening. The vaginal opening is surrounded by two pairs of skin flaps called the labia (meaning lips).
A tiny sensory organ, the clitoris is situated at the front of the vulva where the labia folds join. There are openings to the urethra (the channel that carries pee from the bladder to the outside of the body) and vagina between the labia.
When girls grow sexually mature, pubic hair covers the outer labia and the pubis.Vagina, uterus, Fallopian tubes, and ovaries are the inner reproductive organs of a female. The vagina is a hollow, muscular tube extending from the opening of the vagina to the uterus.
The vagina can grow and contract because it has muscular walls. This capacity to grow larger or smaller enables the vagina to accommodate something as slim as a tampon and as broad as a child. The muscle walls of the vagina are lined with mucous membranes that keep it moist and protected.
A very thin piece of skin-like tissue called the hymen partly covers the opening of the vagina. Hymens are often different from female to female.The vagina connects to the cervix (meaning neck) with the uterus, or womb.
There are powerful, dense walls in the cervix. The cervix's opening is very tiny (no wider than a straw), which is why inside a girl's body a tampon can never get lost. The cervix may expand during pregnancy to enable a child to pass.

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Explain the term:-
Implantation

(in a mammal) the attachment of the fertilized egg or blastocyst to the wall of the uterus at the start of pregnancy.

What is Menarche?

What are the two main functions of the fluid secreted by seminal vesicles and the prostate gland in human male reproductive system?

i) The prostate gland is a male reproductive organ whose main function is to secrete prostate fluid, one of the components of semen.

ii) While the muscles of the prostate gland also help propel this seminal fluid into the urethra during ejaculation.

iii) Seminal vesicles release up to 60% of the fluid found in semen, the other 40% is produced by the prostate and bulbourethral glands.

iv) The fluid produced by seminal vesicles will contain Fructose, which is a sugar that is produced to provide energy for swimming sperm cells.

Draw a labelled diagram to show interrelationship of accessory ducts in a human male reproductive system.

The male accessory ducts (vasa efferentia, epididymis, vas deferens, and rete testis) serve to store spermatozoa and to transport them outside urethra during ejaculation.
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Name the largest cell in human body.

The largest cell of the human body is Neuron (nerve cell)

The figure shows a foetus in the uterus. Define implantation.

Answer :

i) In humans, implantation is the stage of pregnancy at which the embryo adheres to the wall of the uterus.

ii) At this stage of prenatal development, the conceptus is called a blastocyst.

iii) It is by this adhesion that the embryo receives oxygen and nutrients from the mother to be able to grow.

Differentiate between spermatogenesis and oogenesis on the basis of
(i) Time of initiation of the process
(ii) Site of completion of the process
(iii) Nature of meiotic division undergone by gamete mother cells

(i) Time of initiation of the process

Spermatogenesis - It starts in males at the age of puberty due to a significant increase in the secretion of Gonadotropin-Releasing Hormone (GRH).

Oogenesis - It is initiated in females during the embryonic development stage when a couple of oogonia are formed within each fetal ovary. No more oogonia are formed or added after birth.

(ii) Site of Completion of the process

Spermatogenesis - It is completed in the testes and mature sperms are released from the seminiferous tubules and are transported by the accessory ducts.

Oogenesis - It is completed in the female reproductive tract, in the ovary. The Graffian follicle ruptures to release the secondary oocyte from the ovary (ovulation). The secondary oocyte is converted to ovum (mature female gamete).

(iii) Nature of meiotic division undergone by the gamete mother cells

Spermatogenesis- It involves equal cytoplasmic division.

Oogenesis- It involves unequal cytoplasmic divisions.

In human females, an event that reflects onset of reproductive phase is :
A. Growth of body
B. Changes in hair pattern
C. Changes in voice
D. Menstruation

In human females an event that reflects the onset of reproductive phase is menstruation. The phase is marked by the discharge of the endometrial lining and the unfertilized egg through the vagina, that takes place for about 5-7 days.

What is the function of prostate glands and seminal vesicles

Prostrate gland is a male reproductive organ which secretes prostrate fluid which is a component of semen. The seminal vesicles secretes a significant proportion of the fluid that ultimately becomes semen. The secretions of seminal vesicle and prostrate gland provides nutrition and protection to sperm and also make their transport easy.

Name the homones and state their role involved in controlling spermatogensis in humans.

Fill in the blank.

In male and female reproductive system of human, _______ gland is same.

In male and female reproductive system of human, bulbourethral gland is same.

Fill in the blank.

Implantation of embryo occurs in _____

Implantation of embryo occurs in uterus.

Answer the following question is short.

What is menstrual cycle? Describe it in brief.

The menstrual cycle is the reproductive cycle in all primates and begins at puberty (menarche).
• In human females, menstruation occurs once in 28 to 29 days. The cycle of events starting from one menstruation till the next one is called the menstrual cycle.
• During the middle of the menstrual cycle, one ovum is released (ovulation).
• The cycle starts with the menstrual flow (3 to 5 days), caused due to the breakdown of the endometrium of the uterus. Blood vessels in the liquid state are discharged, but this occurs only when the ovum is not fertilised.
• It is followed by the follicular phase. In this phase, the primary follicles mature into the Graafian follicles. This causes the regeneration of the endometrium, follicular growth, and the growing follicles to produce oestrogen.
• The LH and FSH are at their peak in the middle of the cycle ($$14^{th}$$ day) and cause the rupture of the Graafian follicles to release an ovum. This phase is called the ovulatory phase. • In the absence of fertilisation, the corpus luteum degenerates, thereby causing the disintegration of the endometrium and the start of a new cycle.

After observing figure answer the following.
Read the following statements and label them in the figure:
(i) The part which produces female gametes.
(ii) The part where development of the baby takes place.
(iii) The part through which the developing embryo passes to reach the uterus.

(i) Ovary: The part which produces female gametes (Ova).

(ii) Uterus: It is the part of female reproductive system where development of the baby takes place.

(iii) Oviduct: It is the part of the female reproductive system through which the fertilised and developing embryo passes to reach the uterus.

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Unscramble the underlined words in the following sentences.
Reproductive life of a woman lasts from hacreemn to spauoemen.

Reproductive life of a woman lasts from Menarche to Menopause.
Menarche is the first occurrence of menstruation and marks the beginning of the reproductive period.
Menopause is the end of menstruation and marks the end of the reproductive period of women.

Where does implantation of embryo take place in mother?

The implantation of the embryo takes place in the Endometrial lining of the uterus.

What is the role of cervix in the human female reproductive system?

Along with the vagina: the cervix forms the birth canal. Parturition happens through the birth canal.

Write a short note on cleavage and implantation.

After fertilization, the zygote undergoes many mitotic divisions. This results in a multicellular structure which appears like a ball. This process is called cleavage and the structure is called blastula. After that, the embryo moves down the uterus and gets implanted in the endometrium. This is called implantation. Implantation marks the beginning of pregnancy.

What is gametogenesis?

Answer:

Gametogenesis, in embryology, the process by which gametes, or germ cells, are produced in an organism. The formation of egg cells, or ova, is technically called oogenesis, and the formation of sperm cells, or spermatozoa, is called spermatogenesis.

Gametogenesis is important because it is the process that produces your functional gametes (egg and sperm cell) either through meiosis from a diploid cell or mitosis from a haploid cell (plants). These gametes are important because this allows genetically-varied organisms (offspring) to be formed.

What is the role of vas deferens?

Vas deferens is a tube-like structure that carries sperms from the epididymis of the testis to the penis.

What is zygote?

Answer:

Zygote is a fertilized egg cell that results from the union of a female gamete (egg, or ovum) with a male gamete (sperm).

In the embryonic development of humans and other animals, the zygote stage is brief and is followed by cleavage, when the single cell becomes subdivided into smaller cells.

A zygote forms when a sperm penetrates the outer surface of an egg. This happens in the fallopian tube. While the zygote stage is very brief, lasting only the early days of conception, it is important. The single-celled zygote contains all of the genetic information required to form a fetus.

Why are menstrual cydes absent during pregnancy.

High levels of progesterone and estrogens during pregnancy suppresses the gonadotropins which are required for the development of new follicles. Therefore, a new cycle cannot be initiated.

Female reproductive organs and associated functions are given below in column A and B. Fill the blank boxes.

Column A Column B
Ovaries Ovulation
Oviduct (a)
(b) Pregnancy
Vagina Birth

Column A	Column B
Ovaries	Ovulation
Oviduct	Fertilization
Uterus	Pregnancy
Vagina	Birth

What is the significance of epididymis in male fertility?

Secretion from epididymis is essential for maturation and motility of sperms. Secretions from vas deferens, prostate, and seminal vesicles are also involved in this. Thus, these organs: along with epididymis play an important role in male fertility.

Which type of cell division forms spermatids from the secondary spermatocytes?

Meiosis results in formation of spermatids from secondary spermatocytes.

(a) How many spermatozoa are formed from one secondary spermatocyte?
(b) Where does the first cleavage division of zygote take place?

(a) Four spermatids are formed from one secondary spermatocyte. All of them subsequently develop into spermatozoa through a process called spermiogenesis.
(b) The first cleavage division of zygote takes place in the ampullary-isthmus junction.

Meiotic division during oogenesis is different from that in spermatogenesis. Explain how and why?

It is true that the meiotic division during oogenesis is different from that in spermatogenesis. Following are the details about significant differences between them:
$$*$$ In case of spermatogenesis, meiotic division begins at the time of puberty. This is the time when spermatogenesis begins in a male. On the other hand, oogenesis begins in the female when the female is still in the womb. Thus. It can be said that the meiotic division during oogenesis begins when the girl child is still in the womb.
$$*$$ Formation of primary oocytes stop by the 20th week of gestation of the female child. On the contrary. production of spermatocytes continues throughout the reproductive phase of a male.
$$*$$ In case of spermatogenesis. all the stages of meiosis take place quickly after one another and there is no time lag between them. In the case of oogenesis, meiosis is suspended at the Prophase I state.
$$*$$ Meiosis resumes only once the puberty begins.

Following are some possible reasons for this difference in patterns of oogenesis and spermatogenesis:
$$*$$ Male gametes need to be formed in a very large number to ensure fertilization.
$$*$$ Female gametes are not exposed to external hazards and hence a fewer number of them would be enough. Limiting the production of female gametes helps In the conservation of resources from the female body. The resources can then be properly utilized during the development of foetus.

What role does pituitary gonadotropins play during follicular and ovulatory phases of menstrual cycle? Explain the shifts in steroidal secretions.

FSH and LH are the two pituitary gonadotropins that play an important role during follicular and ovulatory phases of the menstrual cycle.
$$*$$ FSH stimulates the release of ovum from the Graafian follicle. it also stimulates the development and subsequent rupture of the Graafian follicle. Thus, FSH plays a major role during the follicular and ovulatory phases.
$$*$$ The given figure shows varying levels of LH, FSH, and steroid hormones during follicular and ovulation phases of the menstrual cycle.
$$*$$ At this stage, the level of estradiol (a steroid hormone) increases. This suppresses the level of Luteinizing hormone (LH). Once the level of estradiol reaches a threshold level; its effect is reversed.
$$*$$ After that. level of estrogen (another steroid hormone) increases. This stimulates a surge in levels of LH. A high level of LH stimulates the development of corpus luteum and proliferation of the endometrium. This marks the beginning of the luteal phases.

What are the events that take place in the ovary and uterus during follicular phase of the menstrual cycle?

Following events takes place in the ovary and uterus during the follicular phase of the menstrual cycle:
(a) The primary follicle in the ovary grows to become a fully mature Graafian follicle.
(b) The endometrium in the uterus regenerates through proliferation.
(c) Estrogen is secreted by granulosa cells of growing follicles.

Give the names and functions of the hormones Involved In the process of spermatogenesis. Write the names of the endocrine glands from where they are released.

Hormone	Function	Origin of hormone
Gonadotropin Releasing Hormone (GnRH)	Act on anterior pituitary gland and stimulates the release of LH and FSH	Hypothalamus
Luteinizing hormone (LH)	Acts at Leydig cells and stimulates secretion of androgen.	Pituitary
Follicle Stimulating Hormone (FSH)	Acts on Sertoli cells and stimulates factors which are involved in spermatogenesis.	Pituitary

What is the significance of ampullary-isthmic Junction in the female reproductive tract?

First cleavage division of zygote occurs in the ampullary-isthmic junction in the female reproductive tract.

The zygote passes through several developmental stages till implantation. Describe each stage briefly with suitable diagrams.

The following figure shows various stages of zygote development till implantation:
(a) The zygote divides into a two-cell stage called cleavage. This development takes place when the zygote is still in the isthmus.
(b) The cleavage undergoes further rounds of mitosis to form 2, 4. 8, and finally 16-celled stage. These daughter cells are called a blastomere.
(c) The 16-celled stage is called the morula.
(d) The morula changes into blastocyst; with more rounds of meiosis. At this stage, the blastomeres are arranged in an outer layer of cells: called trophoblast and an inner mass of cells.
(e) Implantation to the uterine wall happens at the blastocyst stage.

Mention the importance of LH surge during menstrual cycle.

A rapid surge in LH induces the rupture of the Graafian follicle. This facilitates the release of an ovum. Thus, the rapid surge in LH facilitates ovulation.

A human female experiences two major changes, menarche and menopause during her life. Mention the significance of both the events.

Significance of Menarche: Menarche marks the onset of puberty. Thus, it marks the beginning of the reproductive phase in females.
Significance of Menopause: Menopause marks the culmination of the reproductive phase in females.

Explain the structure of ovary.

Structure of Ovary:

Ovaries are paired structures found in the abdominal cavity.

Size of each ovary is 1.5 – 3 cm long and 8 mm thick and shape is like an almond.

It is found behind kidneys in the pelvic region.

Ovary forms ovum and secretes female hormone, estrogen and progesterone.

What kind of cell divisions take place during cleavage?

Mitosis division takes place during cleavage but it is without the growth phase.

State the functions of the following:
(a) Ovary
(b) Testes
(c) Fallopian tubes
(d) Seminal vesicle
(e) Uterus

(a) Ovary: Ova (eggs) and secrete female sex hormones, oestrogen and progesterone are produced by ovaries.

(b) Testes: A pair of testes are present in the human male. The testes produce sperms.

(d) Seminal vesicle: The function of the seminal vesicle is to store sperms and to secrete seminal fluid.

(e) Uterus: The inner lining receives, protects and nourishes the embryo. Contractions of muscular wall expel baby during birth.

Which of the cells function as endocrine gland in the testes? Write the name of the hormone secreted by these cells.

Leydig’s cells performs as an endocrine gland in the testes. It secretes Androgen hormone (testosterone).

Write a brief note on three stages of gametogenesis.

Gametogenesis includes spermatogenesis & oogenesis. It includes three phases -

Multiplication Phase - In this phase, the diploid germ cell divides by mitosis to form diploid oogonia in oogenesis & spermatogonia in spermatogenesis.
Growth Phase - This phase involves only growth in size. It is the longest phase. It results in the formation of the primary oocyte in oogenesis and primary spermatocyte in spermatogenesis.
Maturation Phase - This phase involves meiotic division and it is divided into two phases -

Maturation - I - The diploid primary oocyte/ spermatocyte divides by meiosis-I to form two haploid secondary spermatocytes in spermatogenesis and in oogenesis one secondary oocyte & one polar body is formed.
Maturation - II - In spermatogenesis, the two secondary spermatocytes divide by meiosis-II to form four haploid spermatids which finally convert into four haploid sperms. In oogenesis, the secondary oocyte divides by meiosis-II to form one haploid ootid and one haploid polar body-II.

Describe two structural differences between a mature sperm and a mature egg.

Sperm is microscopic,motile and flagellated while ovum is larger, non-motile, spherical and food-laden cell.

(a) Explain the menstrual phase in a human female. State the levels of ovarian and pituitary hormones during this phase.
(b) Why is the follicular phase in the menstrual cycle also referred as a proliferative phase? Explain.
(c) Explain the events that occur in a Graafian follicle at the time of ovulation and thereafter.
(d) Draw a Graafian follicle and label antrum and secondary oocyte.

a) The reproductive organs of female primates undergo rhythmic changes called as the menstrual cycle. The average cycle in human females is about 28-29 days. The start of menstrual cycle at puberty is known as menarche. It involves four phases: Menstrual, follicular, ovulatory and luteal.

Menstrual phase: It forms the first phase of menstrual cycle which occurs for 3-5 days. The endometrial lining of the uterus breaks down during this phase. The unfertilized ovum, as well as the blood vessels, are discharged from the vagina. It leads to the abdominal cramps due to the contraction of the uterus and abdominal muscles. Estrogen and progesterone levels are low during day 1 of menstrual phase which stimulates the pituitary gland to secrete FSH for follicular maturation.

b) The follicular phase is known as the proliferative phase as in this phase the production and growth of follicles take place. During this phase, one of the follicles matures to become Graafian follicle and uterus endometrium lining undergoes regeneration through proliferation.

c) During mid-cycle, there is rapid secretion of LH hormone which causes LH surge leading to the rupture of Graafian follicle thus releasing the ovum by a process called ovulation. During ovulation, only the egg comes out of the follicle while the remaining ruptured follicle remains on the surface of the ovary. Within two weeks the follicle gets transformed into a structure known as corpus luteum, It releases progesterone and small amounts of oestrogen, both of which maintain the thickening of the walls of the uterus for implantation. If pregnancy takes place, the high levels of progesterone are maintained and if pregnancy does not occur then the corpus luteum withers away on day 22. There is a drop in progesterone level and wall of the uterus lining falls off leading to menstruation.

d) An image of Graafian follicle showing antrum and secondary oocyte is given above.

Give the functions of the following:
(a) Corpus luteum (b) Endometrium
(c) Acrosome (d) Sperm tail
(e) Fimbriae

(a) Corpus luteum − Corpus luteum is formed from the ruptured Graafian follicle. It secretes progesterone hormone during the luteal phase of the menstrual cycle. A high level of progesterone inhibits the secretions of FSH and LH, thereby preventing ovulation. It also allows the endometrium of the uterus to proliferate and to prepare itself for implantation.

(b) Endometrium − It is the innermost lining of the uterus. It is rich in glands and undergoes cyclic changes during various phases of the menstrual cycle to prepare itself for the implantation of the embryo.

(c) Acrosome − It is a cap-like structure present in the anterior part of the head of the sperm. It contains hyaluronidase enzyme, which hydrolyzes the outer membrane of the egg, thereby helping the sperm to penetrate the egg at the time of fertilization.

(d) Sperm tail − It is the longest region of the sperm that facilitates the movement of the sperm inside the female reproductive tract.

(e) Fimbriae − They are finger-like projections at the ovarian end of the fallopian tube. They help in the collection of the ovum (after ovulation), which is facilitated by the beating of the cilia.

Implantation, Parturition, Ovulation, Gestation, Fertilisation (Stages leading to formation of foetus and birth)

The process of ovulation will release the egg from the ovary. This ovary then undergoes the process of fertilization with the sperm in one of the fallopian tube. The fertilized egg then moves towards the uterus where it gets implanted. After successful implantation, the embryo develops inside the uterus during the gestation period. After the foetus is fully developed, then it is delivered by the process of parturition from the uterus to the vagina to outside world.

Define menstrual cycle and explain its various phases with diagram.

The menstrual cycle is a reproductive cycle which takes place in the females of the group of primates. The menstrual cycle is divided into four phases:

(i) Menstrual phase: It extends from 1$$^{st}$$ to 4$$^{th}$$ day of the cycle. It occurs in the absence of fertilization. During this phase, bleeding occurs as the endometrium of the uterus is sloughed off. The menstrual flow consists of secretion of endometrial glands, cell debris, unfertilized ovum. After 4$$^{th}$$ day, once again the FSH secretion from the pituitary is resumed and the new follicle starts developing.

(ii) Follicular phase: When the ovary is in this phase, uterus enters in the proliferative phase. This takes place from 5$$^{th}$$ to 13$$^{th}$$ day of the cycle. During this phase new primordial follicle in the ovary develops due to the action of FSH from the pituitary. It gradually changes into Graafian follicle and production of oestrogen starts. Only one follicle develops in one cycle.Corresponding to the changes in the ovary, uterus also undergoes proliferation. Endometrial glands, stimulated by oestrogen do repair process of uterus.

(iii) Ovulatory phase: During this phase, ovulation takes place. It usually occurs on 14$$^{th}$$ day. Mature Graafian follicle ruptures due to LH secreted by pituitary. Graafian follicle bursts and releases the ovum. This ovum along with the follicular fluid is picked up by the fimbriae of infundibulum of fallopian tube. It passes through fallopian tube, where, if it happens to meet a sperm, it is fertilized. If not fertilized, the ovum degenerates.

(iv) Luteal phase: It corresponds with the secretory phase in uterus. It takes place between 15$$^{th}$$ to 28$$^{th}$$ day of the cycle.

Ovarian changes: In the ovary, corpus luteum is formed from empty Graafian follicle. Progesterone is secreted now. If ovum is fertilized, corpus luteum is retained. LH and LTH from pituitary help in the maintenance of corpus luteum. If ovum is not fertilized, corpus luteum degenerates and forms corpus albicans.

Uterine changes: Under the influence of progesterone, there is increase in the thickness of endometrium. Endometrial glands grow and become secretory. Progesterone is responsible for the maintenance of pregnancy. When fertilized ovum reaches the uterus, it is implanted and placenta is formed. Till placenta becomes functional corpus luteum keeps on producing progesterone. But when progesterone source is cut off, endometrium sloughs off and menstruation begins.

Write an essay on menstrual cycle.

The menstrual cycle is a reproductive cycle that takes place in the females of the group of primates. The menstrual cycle is divided into four phases:

(i) Menstrual phase: It extends from 1$$^{st}$$ to 4$$^{th}$$ day of the cycle. It occurs in the absence of fertilisation. During this phase, bleeding occurs as the endometrium of the uterus is sloughed off. The menstrual flow consists of secretion of endometrial glands, cell debris, unfertilized ovum. After 4$$^{th}$$ day, once again the FSH secretion from the pituitary is resumed and the new follicle starts developing.

(ii) Follicular phase: When the ovary is in this phase, the uterus enters in the proliferative phase. This takes place from 5$$^{th}$$ to 13$$^{th}$$ day of the cycle. During this phase new primordial follicle in the ovary develops due to the action of FSH from the pituitary. It gradually changes into the Graafian follicle and the production of estrogen starts. Only one follicle develops in one cycle. Corresponding to the changes in the ovary, the uterus also undergoes proliferation. Endometrial glands, stimulated by estrogen do repair process of the uterus.

(iii) Ovulatory phase: During this phase, ovulation takes place. It usually occurs on 14$$^{th}$$ day. Mature Graafian follicle ruptures due to LH secreted by the pituitary. Graafian follicle bursts and releases the ovum. This ovum along with the follicular fluid is picked up by the fimbriae of the infundibulum of the fallopian tube. It passes through the fallopian tube, where, if it happens to meet a sperm, it is fertilised. If not fertilised, the ovum degenerates.

(iv) Luteal phase: It corresponds with the secretory phase in the uterus. It takes place between 15$$^{th}$$ to 28$$^{th}$$ day of the cycle.

Ovarian changes: In the ovary, corpus luteum is formed from an empty Graafian follicle. Progesterone is secreted now. If the ovum is fertilised, corpus luteum is retained. LH and LTH from pituitary help in the maintenance of corpus luteum. If the ovum is not fertilised, corpus luteum degenerates and forms corpus albicans.

Uterine changes: Under the influence of progesterone, there is an increase in the thickness of the endometrium. Endometrial glands grow and become secretory. Progesterone is responsible for the maintenance of pregnancy. When fertilised ovum reaches the uterus, it is implanted and the placenta is formed. Till placenta becomes functional corpus luteum keeps on producing progesterone. But when progesterone source is cut off, endometrium sloughs off and menstruation begins.

Short / Long Answer question Type :
At what stage does the developing human embryo get attached to the inner lining of the mothers uterus? Explain the developmental changes the embryo undergoes till the establishment of three germinal layers .

Two-celled embryo/zygote undergoes a series of divisions. One cell divides first so that a 3 cell stage of the embryo is formed, followed by a 4-cell stage, a 5-stage cell etc.
This process of subdivision of the ovum into smaller cells is known as cleavage.
As cleavage precedes the ovum has 16 cells. It is called the morula. It is still surrounded by the zona pellucid.
In a cut section of the morula, an inner cell mass is seen which is completely surrounded by an outer layer of cells.
The cells of the outer layer give rise to a structure termed as the trophoblast.

The cells of the trophoblast help in providing nutrition to the embryo. Some fluids pass into the morula from the uterine cavity and partially separates the cells of the inner cells mass from the trophoblast.
As the quantity of fluid increases, the morula acquires the shape of a cyst.
The cells of the trophoblast become flattened and the inner call mass gets attached to the inner side of the trophoblast on the one side, Now the morula is termed as a blastocyst.
The trophoblast has the property of being able to stick to the uterine epithelium or endometrium and trophoblast cells have the capacity to eat up other cells. So they invade and burrow into the tissues to which they have come in contact.
As the embryo travels down the uterine tube and the uppermost part of the uterine cavity, it is prevented from sticking to the epithelium by the zona pellucida.
During this period embryo receives nutrition partly from the substances stored within the ovum and partly by diffusion from the uterine secretions.
By the time a blastocyst is formed embryo needs additional sources of nutrition.
This nutrition is received, when the blastocyst sticks to the uterine endometrium and gets implanted in it. Zona pellucida disappears soon after blastocyst reaches the uterine lumen.
The function of the zona pellucida is to prevent implantation of the blastocyst at an abnormal site. As the blastocyst develops further it gives rise not only to tissues and organs of the embryo but also to a number of structures that supports the embryo and help it to acquire the form of a 3 layered disc.
This disc is called Embryonic disc.
The 3 layers that constitute this embryonic disc are :

1. Endoderm

2. Ectoderm

3. Mesoderm.

Application Based Questions :
Why not all copulations lead to fertilization and pregnancy?

Fertilization can only occur if the ovum and sperms are transported simultaneously to the ampullary-isthmic Junction of the fallopian tube. This is the reason why not all copulations lead to fertilization and pregnancy.

Short / Long Answer question Type :
Tell the functions of each part of a sperm cell.

1. Head -

Head of human sperm is derived from the nucleus.
It contains mainly DNA.
It is covered by a cap-like structure termed as an acrosome.

2. The Neck -

The neck is narrow. It contains a funnel shaped basal body and a spherical centriole.
Basal body is also called as the connecting piece because it helps to establish a union between the head and the remaining part of the spermatozoon.

3. Middle piece -

It consists of the mitochondrial spiral, which provides the energy to the sperm to move ahead into the fallopian tube.

4. Tail -

The tail is covered by a fibrous sheath.
It is 55 µm in length.

Image result for Tell the functions of each part of a sperm cell.

Application Based Questions :
Identify A, B, C and D with reference to gametogenesis in humans, in the flow chart given below

A - LH (Luteinizing hormone)
B - Sertoli cells
C - Testosterone
D - Stimulates spermiogenesis.

Differentiate between seminiferous tubules and Leydig cells.

Seminiferous tubules are tiny, highly convoluted tubules present in the testis. The basement membrane of these tubules is lined by highly specialised cells called spermatogonia and the spermatozoa occupy the central part of the lumen of the seminiferous tubule. On the other hand, leydig cells are present in between the seminiferous tubules. These cells secrete the male hormone, testosterone.

Very short answer type.
To which structures do the mesovarium, ovarian ligament, and suspensory ligament anchor the ovary?

Mesovarium, to broad ligament of the uterus and the uterine tube; ovarian ligament, to uterus; suspensory ligament, to pelvic wall.

Differentiate between :
Spermatogenesis and spermiogenesis

The formation of male gametes (spermatozoa) in the testis is called spermatogenesis, whereas spermiogenesis is a step of spermatogenesis that includes the process of transformation of a circular spermatid to a spermatozoon.

Define spermiation?

Spermiation is the process by which the mature spermatids gets released from the Sertoli cells into the seminiferous tubule lumen before moving to the epididymis.

A woman can give birth to how many children in her lifetime?

A lady would ovulate multiple times in her regenerative window between 13 - 51 years ( 38 years ).be that as it may, pregnancy takes multi-month and ovulation continues averagely following a couple of weeks. so this will give multi-month span between conveyances. will give you around a hypothetical most extreme of a 40 pregnancy for each life ( with incredible fortunes and fortunes slighting the unsuccessful labor expanding likelihood with expanding age and decline ripeness with expanding age ).

Define gametogenesis. Name two types of gametogenesis. Give a Schematic represenation of spermatogenesis in humans.

Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes.

There are two types of gametogenesis:-

• Spermatogenesis

• Oogenesis

Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules. These cells are called spermatogonial stem cells.

Draw a diagram of the sectional view of human seminiferous tubule and label its parts.

diagram is shown
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Write a short note on ovum and sperm.

Ovum is the female cell produced in the ovary of a female. Sperm is the male cell produced in the testis. Sperm cells are the smallest cell in the male body. Ovum, also known as egg cell and is the largest cell in the female body.

The male gamete which is long, motile, flagellated cell and is differentiated into head, neck, middle piece and tail. Cytoplasm is present in large amounts. Sperms are surrounded by the plasma membrane. The nucleus contains X or Y chromosome.

The female gamete, where the cells are rounded spheres and non-motile, though not differentiated into different regions. Cytoplasm is present in small amounts. Ovum is present in egg envelopes. The nucleus contains X chromosomes as sex chromosomes.

What happens when the egg is not fertilised?

When the egg is not fertilized, it is shredded off from the body and menstrual cycle takes place. Ovary releases one egg every month. At the same time, the uterus also prepares itself to receive a fertilized egg. The endometrium lining becomes thick and spongy for carrying embryo. It would also nourish the embryo if had fertilization taken place. IF the egg is not fertilized, this lining breaks. This results in the discharge of blood and mucous through vagina. This menstrual cycle last for around 5 to 7 days until all the debris of endometrium along with blood is discharged.

Where do the following functions occur in humans?

Production of egg
Fertilization
Implantation of zygote

Production of egg - It occurs in the ovary.

Fertilization - It occurs at the end of the fallopian tube.

Implantation of the zygote- It takes place in the uterus.

State the difference between sperm and egg in a tabulas form with the diagram.

The differences between egg and sperm are

1.Egg cells are also called oocytes or ova. These cells are considered to be the largest cells in the human anatomy. On the other hand, sperm cells are the smallest cells in the human anatomy.

2.Egg cells are the roundest cells. They almost make a perfect circle. The nucleus of this cell is dissolved because of the large volume of cytoplasm or cell fluid until just earlier than conception. Sperm cells have a small nucleus with a small volume of cell fluids, a long tail, and some mitochondria. They possess barely any content. They are the straightest type of cell.

3.Egg and sperm cells are each other’s contrast. The disparities are great; at the same time they fit in with each other. If we notice that the ovum is a sphere-like cell and the sperm as a consequent straight radius.

4.Egg cells are composed mainly of cell fluids internally. These cells allow movements. The nucleus is spread out which enables the chromosomes do not fold up. This cell is mobile and active internally. On the other hand, sperm cells have barely any cell fluids and are concentrated in their own DNA structures.

5.Egg cells can only exist for 12-24 hours or approximately 1 day in their natural flora and can’t be conserved. Sperm cells can exist for about 3 to 5 days in a woman’s womb and can be conserved and frozen at below 60 ° C.

Write the name of those parts of a flower with serve the same function as the following do in the animals. (i) Testis (ii) Sperm (iii) Ovary (iv) Egg.

The stamen of the flower represents as the male reproductive part. It has two parts called filament and anther. The microsporangia of anther developed and become pollen sacs. They extend longitudinally all through the length of anther and are packed with pollen grains. These are male gametocytes. The gynoecium represents as the female reproductive part. The gynoecium consists of a pistil. The basal bulged part of the pistil is called ovary which consists of ova. The parts of the flower which serve like reproductive organs in an animal are;

Testis-stamen

Sperms-pollen grains

Ovary-ovary

Egg-ovum

In human body what is the role of (i) Seminal vesicles
(ii) Prostate glands

Seminal vesicle: It is formed from the Wolffian duct of the embryo. Internally it is lined by glandular epithelium which secretes seminal fluid. This is lubricating , transparent and jelly like substance, which makes 60-70% part of semen. It is slightly alkaline 9pH 7.3). Fructose is found in seminal fluid, it act as fule to sperm.

Prostate glands: Prostate gland secrete slightly alkaline prostatic fluid which is milky, thick, sticky or jelly like. It makes about 30% part of semen and helps in sperm activation. The secretion of prostate glands has citric acid, calcium and phosphate, clotting enzyme and profibrinolysin are present. The secretion of the prostate gland combined with the secretion of seminal vesicle and so the semen gets coagulated.

Corpus luteum gets converted into corpus albicans in absence of fertilization, give reason.

Corpus luteum gets converted into corpus albicans in absence of fertilization as:

1. A corpus luteum is a mass of cells that forms in an ovary and is responsible for the production of the hormone progesterone during early pregnancy.

2. The luteal phase of the menstrual cycle is the time where the body prepares for implantation of a fertilized egg.

3. The role of the corpus luteum depends on whether or not fertilization occurs.

4. If there are no fertilized eggs to implant in the thickened uterine lining, the corpus luteum degenerates in 10-12 days after ovulation and forms the corpus luteum of menstruation and is eventually transformed into a white scar, the corpus albicans.

5. Formation of corpus albicans results body to shed the lining during menstrual bleeding due to low levels of estrogen and progesterone

6. Ultimately leading to the reason for the menstrual cycle to begin again.

Hence, corpus luteum gets converted into corpus albicans in absence of fertilization

Draw labelled diagram of a transverse section of the testis.

1875946_1877956_ans_a6a6f894190e424e9e5545ddc5522bc1.png

During reproduction, the chromosome number (2n) reduces to half (n) in the gametes and again the original number (2n) is restored In the offspring, What are the processes through which these events take place?

Gametogenesis involves meiosis which results in a haploid number of chromosomes In daughter cells. Thus, the chromosome number is half (n) in gametes. Fertilisation is the step in which the chromosome number becomes diploid (2n) because of the fusion of male and female gametes.

Draw a well-labelled diagram of a typical ovule.

The typical ovule of Angiosperms is anatropous ovule.
1882918_1882464_ans_4646b7e830c1474aaa47413a7aec31d9.jpg

(a) Draw a sectional view of human female reproductive system and label the parts where:
(i) eggs develop.
(ii) fertilization takes place
(iii) fertilized egg gets implanted.

(b) Describe, in brief, the changes that the uterus undergoes:
(i) to receive the zygote
(ii) if zygote is not formed.

Explanation -

1. Eggs develop - Ovaries

2. Fertilization takes place- Fallopian tubes.

3. Fertilized egg gets implanted - Uterus

1. To receive the zygote the uterus undergoes many changes to create a friendly environment for the initiation of pregnancy. The lining of a uterus gets thickened and enriched with blood supply to promotes healthy growth. The uterus also increases its secretion to allow easy movement of the zygote for implantation. The uterus also produces rounded cells which cover the whole area towards the uterine cavity, these cells are called decidual cells.

2. If the zygote is not formed the whole layer of the decidual cells sheds off along with blood and mucus in the next menstrual cycle.

Draw the diagram of Human female reproductive system and label the following:
(a) Site of production of egg (b) Site of fertilization (c) Site of zygote implantation

Answer-

A.Ovaries- Site of production of eggs

B. Fallopian tube - Site of fertilization

C. Endometrial lining of uterus - Site of zygote implantation

2145074_1979826_ans_8b51e018152b4129b40d05f1cef66b57.jpg

Draw a neat diagram of the female reproductive system and label the parts associated with the following (a) production of gamete. (b) site of fertilisation (c) site of implantation and. (d) birth canal.

a) Production of gametes - Ovary

b) Site of fertilization - fallopian tube or oviduct

c) Site of implantation - Uterus

d) Birth canal - Vagina

1802362_1851545_ans_cd785d2512f742ee8da354d9a0beae33.jpeg

Describe spermatogenesis with the help of a diagram.

Spermatogenesis:

The formation of the sperms from the germ cells in the testes is called spermatogenesis.
The structural & functional unit of testes is seminiferous tubule.
It is provided with germinal epithelium which is made up of germ cells.
Spermatogenesis is a continuous process but for the convenience of study, it is divided into two steps -

Spermatocytogenesis
Spermiogenesis

Spermatocytogenesis

It results in the formation of four haploid spermatids from one diploid germ cell.
It is further divided into three phases

Multiplication phase
Growth phase
Maturation phase

1. Multiplication phase:

During this phase, the germ cells divide repeatedly by mitosis.
It results in the formation of more cells which are called spermatogonia. The spermatogonia are diploid.

2. Growth phase:

This phase results in the formation of primary spermatocyte.
It is a phase of short duration which does not involve any division.
The spermatogonia exhibit growth due to an accumulation of proteins & chromatin substances.
The primary spermatocytes are also diploid.

3. Maturation phase:

During this phase, one diploid primary spermatocyte divides meiotically to form four haploid spermatids.
It is further divided into 2 phases -

Maturation-I:

It involves meiosis-I which is also called a reductional division.
The diploid primary spermatocyte divides to form two haploid secondary spermatocytes.

Maturation-II:

It involves meiosis-II which is also called an equational division.
The two secondary spermatocytes divide to form four spermatids.

2. Spermiogenesis:

During this phase, a non-motile & tail-less spermatid transforms into a motile & tailed sperm.
There is no division during the spermiogenesis and one spermatid forms only one sperm. It is also called as spermatogenesis.
The changes during the spermiogenesis result in the formation of the head, middle piece & tail in the sperm.
The various changes during spermiogenesis are of 2 types -

(1) Changes in Cytoplasm:

During spermiogenesis, most of the cytoplasm of the spermatid is visiting in the form of cytoplasmic residue.
The other changes in the cytoplasm are as follows -

Changes in the Centriole:

The spermatid has two centrioles. During the process of spermiogenesis, one centriole moves anteriorly and occupies a position in the notch of the nucleus. It is called proximal centriole.
The second centriole assumes the slightly posterior position and forms the neck of the sperm. It is called distal centriole.
Both the centrioles in the sperm are situated at a right angle to each other. The distal centriole gives rise to an axial filament which is found in the middle piece & tail of the sperm.
The axial filament exhibits 9+2 fibrillar arrangement out of the 9 fibres are peripheral & double while the 2 fibres are central & single.
In the sperms of some species, an additional ring centriole is present in the posterior part of the middle piece. However, it's function is obscure.

2. Changes in Mitochondria:

During the process of spermiogenesis, all the mitochondria of the spermatid fuse to form a nebenkern or Jensen's sheath.
The nebenkern along with little cytoplasm forms a spiral sheath around the anterior end of the axial filament which is called as manchette.
The nebenkern provides required energy to the sperm.

3. Formation of Acrosome:

The anterior most part of the sperm is called an acrosome. It is formed by the Golgi body during the spermiogenesis.
Firstly, one of the vacuoles of the Golgi body develops an acrosomal granule.
Gradually, the acrosomal granule accumulates lytic enzymes and forms a cap-like structure on the anterior end of the nucleus.
Soon this cap gets bounded by a single unit plasma membrane and forms an acrosome.
The best parts of the Golgi body are lost in the form of Golgi rest.

(2) Changes in the Nucleus:

There is a loss of water and unwanted substances from the nucleus during spermiogenesis.
Nucleolus & RNA are lost gradually.
The nucleus slightly elongates and become narrow.
The remaining DNA with nucleoproteins get condensed in the nucleus.
Golgi body Proacrosomal granule Acrosomal granule

1865688_1879141_ans_8118141a9864462987e8a2fcfd48442d.jpg

Draw line diagrams of spermatogenesis and oogenesis.

1865625_1879216_ans_bfe00caaa7fc40518890d42c6a7b2302.jpg

Column A	Column B
Ovaries	Ovulation
Oviduct	(a)
(b)	Pregnancy
Vagina	Birth

Human Reproduction - Class 12 Medical Biology - Extra Questions

Write two major functions of testis.

What is parturition? Which hormones are involved in induction of parturition?

The female is in the reproductive phase between menarche and_________

Name the body part in which the embryo develops.

Define zygote.

Each question contains statements given in two columns which have to be matched. Statements in column have to be matched with statements in column II.

What is a menstrual cycle?

What is menopause?

Schematically represent and explain the events of spermatogenesis in humans.

Describe the path that sperm take while leaving the body.

What do the sperms do after being released?

In which female reproductive organ does the embryo get embedded?

Write the location and function of the following in human testes:(a) Sertoli cells (b) Leydig cells

Mention the difference between spermiogenesis and spermiation.

(a) Draw a diagram of the structure of a human ovum surrounded by corona radiata. Label the following parts:(i) Ovum (ii) Plasma Membrane (iii) Zona Pellucida(b) State the function of Zona Pellucida.

Draw a labelled diagram of the sectional view of a human seminiferous tubule. (six parts to be labelled)

What is spermatogenesis? Briefly describe the process of spermatogenesis.

Draw a labelled diagram of male reproductive system.

(a) Draw a labelled diagrammatic view of human male reproductive system.(b) Differentiate between:(i) Vas deferens and vasa efferentia(ii) Spermatogenesis and spermiogenesis

Draw a labelled diagram of sperm.

Describe the structure of a seminiferous tubule.

Name the hormones involved in regulation of spermatogenesis.

Define spermiogenesis and spermiation.

What are the major components of seminal plasma?

Draw a labelled diagram of a Graafian follicle.

Why do fish and frog produce a huge number of eggs each year?

What are the major functions of male accessory ducts and glands?

When an ovum gets fertilized, menstrual cycle stop temporarily in a woman. Give reason.

Give the exact location of the prostate gland.

Find the odd one out and write it:Vagina, Uterus, Vas deferens, Ovary.

Give the biological technical term for complete stoppage of menstrual cycle in females.

Explain the process of spermatogenesis in humans.

Explain the process of spermatogenesis in detail.

What is compaction in the human development?

Define:1) Reparative regeneration 2) Capacitation 3) Menarche

What is corpus luteum and what is its function?

Name the cells that secrete androgens.

Sketch the label 'human male reproductive system'.

Answer in one sentences:What is Menarche?

Explain the phases of spermatogenesis in humans with the help of a diagram.

Draw only ray-diagram of spermatogenesis.

What is spermatogenesis? Explain with the help of diagram.

Why testis are found outside the abdominal cavity in males?

Write only the name of different stages of human reproduction.

Write four differences between spermatogenesis and oogenesis.

The study of physical abnormalities of embryo is called as

Observe the diagram, and answer the question:(a) Identify A and B.(b) What is the function of C?(c) In which of the marked part reduction division takes place? What is the significance of it?

The following graph shows the levels of pituitary hormones during a menstrual cycle. What do 1 and 2 represent?

Mention the exact location of the following:Prostate gland.

The diagram shown below is the longitudinal section of a testis of man. Study it carefully and answer the questions that follow:State the functions of the parts labelled $$1$$ and $$3$$ in the diagram.

Given appropriate biological/ technical terms for the following:The accessory gland in human males whose secretion activates the sperms.

The diagram shown below is the longitudinal section of the testis of man. Study it carefully and answer the following questions. a. Label the parts numbered $$1$$ to $$3$$ in the diagram.b. In which part of the testis sperms are produced?

The diagram shown below is the longitudinal section of a testis of man. Study it carefully and answer the questions that follow: In which part of the testis are the sperms produced?

Define spermiogenesis.

Mention the exact location of the following:a. Epididymisb. Lacrimal glandc. Malleusd. Hydathodese. Pulmonary semilunar valve

Draw a labelled diagram of L.S. of human testis.

Give appropriate biological or technical terms for the following.The onset of menstruation in a young girl.

Choose the ODD one out from the following terms given and name the CATEGORY to which the others belong.Example: Nose, Tongue, Arm, EyeAnswer: Odd Term- Arm, Category- Sense organsProstate gland, Cowper's gland, seminal vesicle, seminiferous tubules.

Define the following term:Implantation

Describe the histology of human testis. Write a note on human sperm.

State the functions of the following:Seminal vesicles

Why is it important that a very large number of sperms should be present in the semen?

Very short answer type.Give the scientific term for the animals which gave birth to young ones.

Application Based Questions :Lack of menstruation is an indication of pregnancy.

Differentiate between :Menarche and menopause

Give basic difference between spermatogenesis and oogenesis.

Very short answer type.Mention the most significant function/role of acrosome:

Short / Long Answer question Type :Write short notes on Menarche

Very short answer type.When and where does spermatogenesis occur in .a human male?

Very short answer type.Define the term spermiogenesis

Application Based Questions :In humans, the testes are situated outside the abdominal cavity. Why?

Very short answer type.What is the proliferative phase in the menstrual cycle? For how many days does it last?

Differentiate between :Vas deferens and vasa efferentia

Fill in the blanks:Zygote is ______ (diploid/haploid)

What is implantation?

Name the functions of Endometrium.

Humans are ______ as they undergo internal fertilization to give birth to newborns.

What is Periodic abstinence?

Enumerate the events in the ovary of a human female during follicular phase of menstrual cycle.

Write the location and function of the following in human testes:
(a) Sertoli cells (b) Leydig cells

(a) Draw a diagram of the structure of a human ovum surrounded by corona radiata. Label the following parts:
(i) Ovum (ii) Plasma Membrane (iii) Zona Pellucida
(b) State the function of Zona Pellucida.

(a) Draw a labelled diagrammatic view of human male reproductive system.
(b) Differentiate between:
(i) Vas deferens and vasa efferentia
(ii) Spermatogenesis and spermiogenesis

Find the odd one out and write it:
Vagina, Uterus, Vas deferens, Ovary.

Define:
1) Reparative regeneration 2) Capacitation 3) Menarche

Answer in one sentences:
What is Menarche?

Observe the diagram, and answer the question:
(a) Identify A and B.
(b) What is the function of C?
(c) In which of the marked part reduction division takes place? What is the significance of it?

Mention the exact location of the following:
Prostate gland.

The diagram shown below is the longitudinal section of a testis of man. Study it carefully and answer the questions that follow:
State the functions of the parts labelled $$1$$ and $$3$$ in the diagram.

Given appropriate biological/ technical terms for the following:
The accessory gland in human males whose secretion activates the sperms.

The diagram shown below is the longitudinal section of the testis of man. Study it carefully and answer the following questions.

a. Label the parts numbered $$1$$ to $$3$$ in the diagram.
b. In which part of the testis sperms are produced?

The diagram shown below is the longitudinal section of a testis of man. Study it carefully and answer the questions that follow:
In which part of the testis are the sperms produced?

Mention the exact location of the following:
a. Epididymis
b. Lacrimal gland
c. Malleus
d. Hydathodes
e. Pulmonary semilunar valve

Give appropriate biological or technical terms for the following.
The onset of menstruation in a young girl.

Choose the ODD one out from the following terms given and name the CATEGORY to which the others belong.
Example: Nose, Tongue, Arm, Eye
Answer: Odd Term- Arm, Category- Sense organs
Prostate gland, Cowper's gland, seminal vesicle, seminiferous tubules.

Define the following term:
Implantation

State the functions of the following:
Seminal vesicles

Very short answer type.
Give the scientific term for the animals which gave birth to young ones.

Application Based Questions :
Lack of menstruation is an indication of pregnancy.

Differentiate between :
Menarche and menopause

Very short answer type.
Mention the most significant function/role of acrosome:

Short / Long Answer question Type :
Write short notes on Menarche

Very short answer type.
When and where does spermatogenesis occur in .a human male?

Very short answer type.
Define the term spermiogenesis

Application Based Questions :
In humans, the testes are situated outside the abdominal cavity. Why?

Very short answer type.
What is the proliferative phase in the menstrual cycle? For how many days does it last?

Differentiate between :
Vas deferens and vasa efferentia

Fill in the blanks:
Zygote is ______ (diploid/haploid)

Rewrite the terms in the correct order so as to be in a logical sequence.
Puberty, menopause, menstruals, menarche, reproductive age.

Give functions of :
(a) Epididymis
(b) Seminiferous tubule

The diagram given alongside is that of a developing human foetus in the womb. Study the same and answer the following question.
How many days does the foetus take to be fully developed?

The onset of menstruation is termed as
Loss of reproductive capacity in women after age of 45-50 years, is termed as___.

Explain the terms

a) Implantation
b) Placenta

Explain the terms :

(a) Implantation
(b) Placenta

Explain the term:-
Implantation

Differentiate between spermatogenesis and oogenesis on the basis of
(i) Time of initiation of the process
(ii) Site of completion of the process
(iii) Nature of meiotic division undergone by gamete mother cells

In human females, an event that reflects onset of reproductive phase is :
A. Growth of body
B. Changes in hair pattern
C. Changes in voice
D. Menstruation