CBSE Questions for Class 11 Medical Biology Chemical Coordination And Integration Quiz 6 - MCQExams.com

• Parathyroid hormone (PTH) is essential for the physiologic maintenance of mineral homeostasis. 
• PTH regulates the mineral transport in bone and kidney and through its secondary actions on mineral transport in the intestine. 
• Calcitonin, in many ways, acts as a physiologic antagonist to PTH. Hence,  Parathyroid hormone is antagonistic to calcitonin

• Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low. 
• It does this through its actions on the kidneys, bones and intestine. 
• Bone parathyroid hormone stimulates the release of calcium from large calcium stores in the bones into the bloodstream. Hence, Parathyroid maintains the calcium level in the blood by action on Bone, Kidney and Intestine.
So, the correct answer is 'All of the above'.

• Erythropoietin is produced by interstitial fibroblasts in the kidney in close association with the peritubular capillary and proximal convoluted tubulin the cell named juxtaglomerular cells. 
•  It is also produced in perisinusoidal cells in the liver. Hence, The cells which produce erythropoietin Juxtaglomerular cells.
So, the correct answer is 'Juxtaglomerular cells'.

•  Eicosanoids are compounds that include prostaglandins, prostacyclins, leukotrienes, and thromboxanes.
• Lipid insoluble hormones such as eicosanoids bind to receptors on the outer surface of the plasma membrane, via plasma membrane hormone receptors.
  
• The amino acid-derived hormones epinephrine and norepinephrine bind to beta-adrenergic receptors on the plasma membrane of cells.
  
• Hence the Epinephrine and eicosanoids find their receptors on the plasma membrane.
• So, the correct answer is 'Plasma membrane'.

• Thyroxine (3,5,3',5'-tetraiodothyronine) is the thyroid hormone produced by follicular cells of the thyroid gland.
• Thyroxine hormone is produced in the thyroid gland from tyrosine and iodine.
  
• Hence the precursor for the synthesis of thyroid hormone is amino acid Throne.
• Tyrosine (symbol Tyr or Y) or 4-dihydroxyphenylalanine is one of the 20 standard amino acids.
  
• So, the correct answer is 'Thyroid'.

• Prolactin levels may be elevated for any number of reasons. One of the more common cause is the formation of a benign tumour on the pituitary gland. 
• This noncancerous growth, known as a prolactinoma, directly secretes excessive prolactin while decreasing the levels of other sex hormones. Hence, The cause of hyperprolactinemia in males may be Tumors

• Thymosin hormones are typically produced by the thymus gland and trigger the creation of T-cells, which are used by the immune system to fight disease. 
• Once puberty occurs in a human, a normal thymus has created the T-cells needed by the body and begins to shrink, eventually being replaced by fatty tissue. Hence, Thymosin helps in the differentiation of lymphocytes.

• Both males and females have glandular tissue within the breasts. However, in females, the glandular tissue begins to develop after puberty in response to estrogen release. 
• Mammary glands only produce milk after childbirth. During pregnancy, the hormones progesterone and prolactin are released. Hence, Estrogen, Prolactin, and Progesterone help in the formation of alveoli of the mammary glands.

• Cholesterol also plays a role in synthesizing the steroid hormones aldosterone, which is used for osmoregulation, and cortisol, which plays a role in metabolism. 
• Cholesterol is also the precursor to bile salts, which help in the emulsification of fats and their absorption by cells. Hence,  Lipids is responsible for steroid production.

• The hypothalamus secretes gonadotropin-releasing hormone (GnRH) which stimulates the pituitary gland into secreting luteinizing hormone (LH) and follicle-stimulating hormone (FSH). 
• LH stimulates testicular Leydig cell secretion of Testosterone whereas FSH stimulates spermatogenesis in Sertoli cells of the seminiferous tubules. 
• An androgen is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. 
• The major androgen in males is testosterone. Hence,  LH hormones trigger the release of androgens.

• The thymus is the primary specialized lymphoid organ of the immune system. It gradually reduces with age.
• T cells or T lymphocytes mature within the thymus. Thymus reduces with age through a process called involution.
• This process has been observed in many vertebrates. This process starts during puberty, in middle age, the thymus changes from a primary lymphoid organ into fatty tissue.
  So, the correct answer is option B.

• The thyroid gland is the largest endocrine gland in the body. It is located in the neck, below the larynx, and in front of the trachea.
• It secretes thyroid hormone, which regulates important metabolic processes connected to our heart rate, body temperature, and energy levels.

• Steroid hormones are lipid hormones. Since they are fat-soluble, they can pass through the cell membrane and bind to protein receptors.
• The receptors could be cytosolic receptors or nuclear receptors. 
• These binding then brings about changes within the cell by activating specific genes.

• Adrenaline is secreted by adrenal medulla during a stressful situation. It increases the metabolic rate, dilation of blood vessels that enter the heart and the brain. 
• The blood vessels of the skin and kidneys constrict to supply more blood to the heart and the brain. Hence it initiates a quick reaction in a person during stress. 
• This is called a fight and flight response. Hence adrenaline is called emergency hormone.
  Thus the correct answer is option C.

• The endocrine part of the pancreas secretes insulin and glucagon, which regulates the level of glucose in the blood, and also somatostatin, which in turn prevents the release of these two.
• Both melatonin and its precursor, serotonin, which are derived chemically from the tryptophan, are synthesized in the pineal gland.
  
• The pituitary gland is called the master gland because it secretes multiple hormones, which in turn controls other glands like growth hormone, thyroid-stimulating hormone, luteinizing hormone, vasopressin, prolactin, etc.
  
• The thymus produces and secretes thymosin, a hormone necessary for T lymphocyte's development and production. 
  

• Parathormone of parathyroid gland reduces the blood phosphate level while increases the blood calcium level. 
• Therefore, its hypersecretion causes hypercalcemia which makes option C correct. 
• Calcitonin hormone stimulates a temporary reduction in the number and activity of osteoclasts and thereby reducing the blood calcium level to normal. Calcitonin is also called as TCT. 
• Aldosterone stimulates renal absorption of sodium ions and water to regulate blood volume. 

Correct option: C.

Explanation:

• Atrial natriuretic peptide/factor- its function is to lower the concentration of water and sodium in the circulatory system. 
• It causes vasodilation and hence leads to a decrease in blood pressure.
• It is a 28 amino acid hormone secreted by the heart atria.

Hence, ‘Atrial natriuretic factor’ is the correct answer.