Muscle Biology

Evertor type of muscles turn the sole outwards.

Voluntary muscles are those that are under conscious control, such as the skeletal muscles in our arms and legs. Involuntary muscles, like those in the heart or stomach, function automatically.

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Ans - b

Ans - 2 Muscular tissues bring about the movement of various body parts.

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Sarcolemma is a thin membrane sheath of the muscle fibre.

Cardiac muscles from the walls of heart. These are intermediate in structure being striated and involuntary. It is meant for automatic and rhythmic contraction. On the other hand skeletal muscles are striated and voluntary, they are most abundant and found attached to skeleton. They are supplied by somatic nerve and hence are under voluntary control.The smooth muscles are non-striated and involuntary. They often encircle or surround viscera. They are supplied by autonomic nervous system. 

Monocyte is the largest white blood cells (WBCs) whereas heamoglobin is found in RBCs. Thus monocyte is not correctly matched with haemoglobin. 

It is the bundle of cardiac muscle fibers that passes from the atrioventricular node to the interventricular septum and then the ventricles. It conducts the electrical impulses that regulate the heartbeat from the right atrium to the left and right ventricles.

During contraction and relaxation of muscles, both I-band and H-zone progressively shorten and disappears.Dark A-band (anisotropic) undergo no change during contraction and relaxation of muscle fibres.

When muscles contract, they have squeezing effect on veins running through them, this is called muscle pump.

During anaerobic situation, lactic acid formation is started by the body cells. Later on, this lactic acid is delivered by the blood to the liver, where lactic acid dehydrogenase enzyme converts lactic acid to pyruvic acid.

 Each actin filament is made of two ‘F’ (filamentous) actins helically wound to each other. Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins. Two filaments of other proteins, tropomyosin also run close to the ‘F’ actins throughout its length. A complex protein troponin is distributed at regular intervals on the tropomyosin. In the resting state, a subunit of troponin marks the active binding sites for myosin on the actin filaments.

  During muscle contraction, actin and myosin interact to form actomyosin. According to sliding filament theory, cross bridge is formed by myosin filament to slide act in filament. During muscle contraction, length of A-band remains constant.