Locomotion And Movement - Class 11 Medical Biology - Extra Questions

Synovial fluid, also called synovia, is a viscous, non-Newtonian fluid found in the cavities of synovial joints. With its egg white–like consistency, the principal role of synovial fluid is to reduce friction between the articular cartilage of synovial joints during movement. The shoulder joints are encapsulated in the synovial membrane, which produces synovial fluid.

The most striking feature of striated muscle fibre is the presence of transverse striations on it. These striations appear as alternate dark and light bands that stretch across the  muscle fibre. These dark and light bands are called A-bands and I-bands respectively. The A-band is made up of myosin filaments whereas the I-band is made up of actin  filaments alone. A-Bands are the anisotropic bands of the sarcomere. I-Bands are the isotropic bands of sarcomere

Skeletal muscle is composed of muscle fibers which have smaller units called myofibrils. There are three types of proteins that make up each myofibril; they are contractile, regulatory and structural proteins. By contractile proteins, we mean actin (thin filament) and myosin (thick filament).

Fibrous joint : sutures in skull

The looseness of the articular capsule and shallowness of the globoid cavity in relation to the size of the head of the humerus.

The hip joint is a ball and socket joint. It is a freely movable joint.

The place where two or more bones are connected is called a joint.

Answer 
Ulna is longer than radius.

There are three types of muscles are-

Carpal/metacarpal of a thumb is joined by the saddle-shaped synovial joint. A synovial joint is a joint where one of the bones forming the joint is shaped like a saddle with the other bone resting on it like a rider on a horse. Saddle joints provide stability to the bones while providing more flexibility than a hinge or gliding joint.

Pubic symphysis or symphysis pubis is a cartilaginous joint which binds the right and the left pubic bones in the pelvic girdle.

Atlas/axis: Pivotal joint

The endoplasmic reticulum in the muscle fiber is known as sarcoplasmic reticulum. It stores calcium ions which regulate the muscle contraction. It helps in the activation of contractile proteins like troponin and tropomyosin.

$$\textbf{Correct Option B}$$

$$\textbf{Solution}$$

$$\bullet$$ The bones of the skull is divided into two parts- cranial bones and facial bones.

$$\bullet$$ The facial bones help in laying the skeleton for the face at the cranial bones form the cranium.
$$\bullet$$ Altogether there are 22 bones present in the skull out of which 8 number of cranial bones and the rest 16 bones are facial bones.
$$\bullet$$ Cranial bones are the bones of the skull which are held together with the help of a permanent fibrous joint called as sutures. 

Smooth muscle - Involuntary

Physiotherapy is the therapeutic process to treat the impairment by mechanical force and movements. It promotes mobility through physical examination, diagnosis and prognosis. Physiotherapists under the supervision of orthopaedic surgeon carry out therapeutic exercise.

Botulism is the condition in which there is paralysis of the muscles. This is a disease which is developed due to the toxin released by the infection of the bacterium Clostridium botulinum. The organism releases botulinum toxin which causes the stiffness and then the paralysis of the muscles. There is difficulty in chewing, swallowing and breathing. 

• The adult human skeletal system consists of 206 bones, as well as a network of tendons, ligaments, and cartilage that connects them. 
  
• The skeletal system has five main functions in the body, three of which are external and visible to the naked eye, and two of which are internal. The external functions are structure, movement, and protection. The internal functions are blood cell production and storage.

A. The structure is the periosteum which is a membrane that covers the outer surfaces of all bones and supports it by acting like a skin to the bones.

Cranial bones are the bones that form the bony case of skull to protect the brain. The type of joint present in between them is called sutures. Suture is a type of fibrous immovable joint present only in skull. The bones are connected by a fiber called Sharpey's fibers. These joints permit slight movement only in the early stages of life during development. Later they become completely immovable. 

• Muscles are composed of tubular cells called myocytes, known as muscle fibres in a striated muscle, and these cells, in turn, contain many chains of myofibrils. 
• The myofibrils are made up of thick and thin myofilaments, which help give the muscle its striped appearance. 
• The thick filaments are composed of myosin, and the thin filaments are predominantly actin, along with two other muscle proteins, tropomyosin and troponin.
•  Myofilaments repeat along the length of the myofibril in sections called sarcomeres.

Intramembranous ossification is the process of bone development from fibrous membranes. It is involved in the formation of the flat bones of the skull, the mandible, and the clavicles. Ossification begins as mesenchymal cells from a template of the future bone

The Haversian canals of a bone are interconnected by surrounding lamellae. These canals along with the lamellae form the Haversian system in bone.

A joint is a structural arrangement where two bones articulate. The joints are essential for the movement of different skeletal structures. The movability in joints varies. On the basis of movability, joints are divided into three groups, namely, fibrous joints, cartilaginous joints and synovial joints.

• Joint is a point where two or more bones meet. They are essential for the movement of different skeletal structures.
  
• Adductor is any muscle that pulls the body part towards the midline.
  
• The abductor is the opposite of the adductor.
  
• Rigor mortis is the extreme rigidity of the body after death due to complete depletion of ATP and phosphocreatine.
  
• A muscle twitch is a small, local, involuntary muscle contraction and relaxation which may be visible under the skin.
  

Voluntary muscles	Involuntary muscles
These muscles are under voluntary control.	These muscles are under involuntary control.
They have sarcomeres.	They do not have sarcomeres.
Examples include Skeletal muscles.	Examples include cardiac muscles.
They contract quickly and powerfully and tire fast.	They contract slowly but tire very slowly.

As the name indicates, at a cartilaginous joint, the adjacent bones are united by cartilage, a tough but somewhat flexible type of connective tissue. These types of joints lack a joint cavity and involve bones that are joined together by either hyaline cartilage or fibrocartilage.

Skeletal Muscles	Smooth Muscles
They are attached to the bones.	They line up the visceral organs viz. Intestines, blood vessels, pupils, etc.
They perform voluntary actions.	They are responsible for involuntary reflexes and actions.
They are well striated.	They lack striation.
Innervated by Peripheral Nervous System i.e. PNS.	Innervated by Sympathetic and parasympathetic nervous systems.
Help perform movements i.e walking, running, jumping, writing, etc.	Responsible for vital body functions i.e. breathing, digestion, urine formation, etc.
Calcium is the most vital substance in the process of skeletal muscle contraction.	Neurotransmitters Acetylcholine or Norepinephrine play important role in smooth muscle contraction.
Types of Skeletal Muscles are Red and White.	Types of Smooth Muscles are Single-unit, Multi-unit, eg. Ciliary muscles.
They contain actin and myosin filaments. The ratio of actin & myosin is 2:1.	They also contain actin and myosin filaments, The ratio of actin and myosin is 10:1.
Troponin is present in skeletal muscles that are Ca-binding proteins responsible for muscle contraction.	Calmodulin is present in smooth muscles that are Ca-binding proteins responsible for muscle contraction.

Joints are the area where two bones are attached to permit the body parts to move and are usually formed by fibrous and cartilaginous connective tissue.

In the muscle cells, myosin and actin are the major components. The muscle cells are always elongated slender and spindle-shaped fibre like cells they are therefore also known as muscle fibres. 

Tetany is a medical condition identified by muscular spasms because of involuntary contractions of muscles. It could be the result of malfunctioning of the parathyroid glands and a consequent deficiency of calcium. Other physiological conditions that increase the action potential frequency of muscle cells or the nerves that innervate muscles could also be responsible for tetany.

$$\textbf{Solution}$$

 Skeletal muscle is affected by Myasthenia gravis. It happens because of immune disorder.

	Voluntary muscles	Involuntary muscles
1.	They are controlled by CNS	They function under ANS
2.	The muscle cells are cylindrical and multinucleate	The muscle cells are spindle shaped and uninucleate
3	Cells are striated	Cells are non-striated
4	Example: Skeletal muscles	Example: muscles of the alimentary canal

There are 3 types of muscles: 
• Skeletal muscle fibre: They are found attached to the skeletal bones and are voluntary. Skeletal muscle fibres are striated and are bundled together in a parallel manner by a sheath of tough connective tissues. 
• Smooth muscle fibre: They are present in the walls of internal organs such as blood vessels, stomach, etc., and are involuntary. Smooth muscle fibres are fusiform (taper at both ends) and non- striated. They are held together by cell junctions and are bundled together in a sheath of connective tissues. 
• Cardiac muscle fibre: This is the only type of muscle present in the heart. They are contractile in nature and are involuntary. Plasma membranes of cardiac cells are fused together by cell junctions, and hence, the cells stick together. Communication junctions present as intercalated discs facilitate the contraction of cardiac cells as a unit. 

Muscle fibre with both end tapers and without strips (striations) is smooth muscle cell.

Skeletal system is important because without it we wouldn't be able to move around, we would lack our normal structure and our internal organs will be at more risk due to lack of protection. Example, the rib cage protects the lungs and the heart, the pelvic bone protects the reproductive organs, the cranium protects the brain etc.

Osteoporosis: 
Main characteristics of the disease are the loss of bone mass means deficiency of organic part (matrix) and minerals (calcium) in the bones. The bone becomes thin, weak and loses elasticity and strength. Chances of bone fracture are increased and slight jerk .
It affects the whole body skeleton but pelvic, wrist, vertebrae, etc are most adversely affected parts. It increases with the age but deficiency of estrogen also caused osteoporosis in old women. It may also be caused by hormones like calcitonin, PTH and glucocorticoids. 

The different types of joints are as follows: 
$$*$$ Immovable joints - Example: Bones of the skull box 
$$*$$ Partially movable joints - Example: Joints between the ribs and breast-bone.
$$*$$ Freely movable joints - Example: Hip joint 
$$*$$ Gliding joint - Example: Ankle bones 
$$*$$ Pivot joint - Example: Joint between axis vertebrae and atlas 
$$*$$ Hinge joint - Example: Joint between finger bones and toes 
$$*$$ Ball and socket joint - Example: Shoulder joint 

Saddle joint.
Explanation:
There are three joints in the thumb:
1. Carpo- metacarpal ( CMC).
2. Metacarpo - phalangeal ( MP)
3. Inter-phalangeal (IP)
The first carpo-metacarpal joint is ( most commonly known as Thumb joint ) a saddle type of joint.
The metacarpo-phalangeal joint is condyloid type of joint. Inter-phalangeal joint hinge joint.

The spinal cord terminates at the intervertebral disc between the second (L2)and the first (L1) Lumbar vertebrae in the form of a cone shaped structure called the conus medullaris.

In the Neck between Atlas and Axis. Pivot joint is found.
The odontoid of Atlas articulates with odontoid fossa of Axis to form Pivot joint which helps in the movement of neck.

Anatomical position creates a common point reference for all who study the human body.
Explanation:
Anatomical position also known as supine position is a standard common point of reference that allows all who study the human body to discuss the parts of the body within the same frame of reference and experience.
The position is standard upright with both arms by the side palms forward with thumbs to the outside and toes pointed forward.

Answer 
The bone injury.
Explanation :
The reason that bone injuries heal faster than cartilage injuries is because of the ability of bone cells to respond to injuries and start dividing to repair the injury.
Cartilage cells tend to be rather inactive once bone has fully grown and the chondrocytes  (specialised cells that live within cartilage) do not respond to injury immediately, and they hardly divide after growth is complete.
Bone cells, on the other hand, are always active, because our bones are constantly being renewed. This process merely speeds up during a bone injury producing chondrocytes  that act as a filler. Over a few weeks, specialised cells called osteoclasts  ingest these cells and osteoblasts replace them with new bone cells.

Answer 

The muscular system is a system that is made up of skeletal muscles, smooth muscles, and cardiac muscles. The skeletal muscles are involved involuntary movements such as that of limbs, smooth muscles are involved in involuntary movement such as that of the gut linings during peristalsis. The cardiac muscles play a role in the blood pumping action of the heart. 

Fibrous joints are the joints between two bones which are connected by dense connective tissues. These joints are immovable joints. They are stronger than all other joints present in the body and provide strength and support to the joint. These are mostly 3 types.

The thin filament of muscle is actin and along with that, there are two other proteins namely Troponin and Tropomyosin. Troponin and Tropomyosin are the additional proteins that are attached to the actin and regulate the formation of cross-bridges and muscle contraction.

The main purpose of sinovial joint is to allow bones to  rotate freely about each other. The articular surfaces of the joint are covered with synovial membrane. The capsule contains synovial fluid. These help in reducing the friction between the articular surfaces of the joint and permits free movement in many planes. There are six types of synovial joints namely, Pivot, saddle, hinge, plane, condyloid, ball and socket joints.

The fluid which is present in the cavity in the joint capsule is known as synovial fluid. This is the fluid which is present between the cartilage of the joints. This fluid provides protection from shock and fracture. This fluid also prevents the friction between the cartilage of the joints. 

When the two bones are joined with the help of connective tissues which allows the movement of the bones is known as the synovial joint. This is a joint which is present between the long bones. The two bones are held with the help of fibrous tissue of the ligament. There is a presence of articular cartilage at the end of the long bones. There is a capsular structure formed by the synovial membrane. This capsule or the cavity is filled with the synovial fluid which prevents friction between the cartilage. These are the type of joints which are present in the different parts of the body which allows the bones to move and the organism can perform functions like locomotion. 

Calcium is the ion responsible for unmasking of active sites of actin filaments leading to cross bridge formation and muscle contraction. As the impulse passes through sarcolemma it reaches sarcoplasmic reticulum and results in release of Ca++ into sarcoplasam. Ca++ attach with troponin-C resulting in moving of tropomyosin away from the active sites of actin permitting cross bridge formation.

$$\textbf{Solution}$$

$$\bullet$$The skull bones are joined at the sutures by fibrous tissues while the bodies of vertebrae are joined by cartilaginous tissue.

$$\bullet$$ The fibrous tissue are composed of collagen fibers and they are immovable tissues.

$$\bullet$$ The cartilaginous tissues are smooth elastic tissues which covers and protects the end part of the bones at the joint. These tissues are easily movable.

A synovial joint, also known as diarthrosis, joins bones with a fibrous joint capsule that is continuous with the joined bones, constitutes the outer boundary of a synovial cavity, and surrounds the bones articulating surfaces. The synovial cavity/ joint is filled with synovial fluid.

As the second peak is higher than the first because the additional influx of calcium ion promotes a second contraction which is added to the first contraction.

$$\textbf{Solution:}$$

Synovial joint is a joint between two bones. It consists of a cartilage lined cavity filled with synovial fluid. It is very flexible type of joint. The synovial fluid is covered by synovial membrane. The synovial fluid acts as lubricating cushion between the two bones and allows the gliding movement past one another. 

The single spinous process (vertebral spine) projects posteriorly at the midline of the back. The vertebral spines can easily be felt like a series of bumps just under the skin down the middle of the back. The transverse and spinous processes serve as important muscle attachment sites. A superior articular process extends or faces upward, and an inferior articular process faces or projects downward on each side of vertebrae. The paired superior articular processes of one vertebra join with the corresponding paired inferior articular processes from the next higher vertebra.

$$\textbf{Solution}$$

$$\bullet$$Cartilaginous joints are connected with the help of cartilage. These joints allowed the movement between the bones.

$$\bullet$$ There are generally two type of cartilaginous joints: Synchondroses and symphyses.

$$\bullet$$ These two joints are classified on the basis of the type of cartilage that is present in them.

$$\bullet$$ In synchondroses cartilaginous joints  the bones are joined with the help of hyaline cartilage. These joints are generally found in growing bones of children. These are immovable joints.

A rubber-like disc is present between each consecutive vertebra. This disc works like a shock absorber. In certain cases, the disc can get displaced and the condition is called slipped disc or prolapsed disc. The slipped disc puts pressure especially on the nerve coming out of the vertebral column. This can cause severe pain in the back. This can also cause pain and numbness in the area which is under control of the affected nerve.

Slipped disc can also cause sciatica pain. The pain in this case begins from the upper thigh and radiates up to the lower legs. In some cases, pins and needle sensation can also persist
for a long duration.

Slipped disc can badly affect the quality of life of the patient.