31 Years NEET Previous Year Questions: Locomotion & Movement - 1 - Free

Myasthenia gravis is a chronic autoimmune muscular disease. It causes 
breakdown of neuromuscular junction due to which the brain loses control over muscles. The symptoms may include drooping eyelids, difficulty in swallowing muscle fatigue, difficult breathing and inability to control facial expressions.

Central part of thick filament, not overlapped by thin filaments is called the ‘H’ zone. ‘H’ zone is also called Hensen’s Line. 

Vertebral column has 12^th or acicvertebrate. The joints between adjacent vertebrae is cartilaginous joint which permits limited movements. Progesterone is secreted by corpus luteum which supports in pregnancy in females

Synovial joints are distinguished by the existence of a synovial cavity filled with fluid between the surfaces of two bones that articulate with each other. These joints facilitate movement, aiding in locomotion and various other activities. Examples of synovial joints include the ball and socket joint found between the humerus and the pectoral girdle, the hinge joint present in the knee, the pivot joint located between the atlas and axis vertebrae, the gliding joint between the carpals, and the saddle joint between the carpal and metacarpal bones of the thumb.

Troponin and myosin are the proteins of striated muscles. They help in muscle contraction.

Thymosin is the hormone released from thymus and helps in stimulating the growth of certain immune cells. Calcitonin is also a hormone released from parafollicular cells of the thyroid gland.

Prolactin is a hormone released by the pituitary gland. Pepsin is a protein-digesting hormone secreted in the stomach.

Rhodopsin is a derivative of vitamin D. Secretin a hormone released into the bloodstream by the duodenum (especially in response to acidity) to stimulate secretion by the liver and pancreas.

So the correct option is C.

Major causative factors of osteoporosis are imbalances of hormones like calcitonin of thyroid, parathormone of parathyroids, and sex hormones and deficiencies of calcium and vitamin D.

Glenoid cavity is found in pectoral girdle.

Elbow joint is an example of hinge joint. The elbow is a hinge joint; it can open and close like a door. Hinge joint is a form of diarthrosis (freely movable joint) that allows angular movement in one plane only, increasing or decreasing the angle between the bones e.g. elbow joint, knee joint etc.

Floating ribs are 2- pairs (11^th and 12^th pair) which are not attached to sternum

When Ca⁺ ions combine with troponin contraction of muscles initiates. During Contraction the Z lines come closer  together and the sarcomere becomes shorter. The length of A band remains constant. I bands shortens  and H-band  narrows.

Darks bands on the myofibril form A-band. Middle part of A-band contains light zones-Hensen line (H-lines). Light  band on myofibril is called I-band. Middle part of I-band contains Z-lines. Sarcomere is part between two Z-lines.

In angular joint articulating surface of one bone is oval and convex whereas that of the other is elliptical and concave, it allows movement only in  two directions e.g. Wrist. Fibrous joints are unmovable joints e.g. Sutures of skull. Cartilaginous joints have little motility due to disc of  fibrocartilage between the articular ends. In gliding joints articulate end of both the bones are either flat or curved to allow gliding movements. e.g. between carpels and wrist.

Each hind limb contain 30 bones namely 1 femur in the thigh, 1 petala in the knee, 1 tibia and 1 fibula in the lower leg, 7 tarsals in the ankle, 5 metatarsals in the sole and 14 phalanges in toes.

Glenoid cavity is a shallow concavity on the lateral side of pectoral girdle in which the head of humerus fits making the shoulder joint.

Movement of Ca²⁺ out in sarcoplasmic reticulum controls the making and breaking of actin and myosin complex actomyosin due to which muscle contraction and relaxation takes place. Albert Szent Gyorgyi worked out biochemical events of muscle contraction.