striped muscles -these muscles are found in the

Question

STRIPED MUSCLES -

1. These muscles are found in the limbs, body walls, tongue, pharynx and beginning of oesophagus and are under the control of animal's will.
2. These muscle fibres are normally attached to the skeleton.
3. Each muscle fibre is an elongated cell surrounded externally by a delicate membrane, the sarcolemma.
4. Its fibres are multinucleated or syncytial in nature.
5. The cytoplasm of each fibre (sarcoplasm) has a large number of myofibrils which are tightly packed.
6. Each myofibril shows dark and light bands of stripes alternating with. each other.
7. The sarcoplasm contains a protein pigment myoglobin.

 

FUNCTIONS-

1. These muscles are under the control of animal's will.
2. Calcium is an essential element for the contraction of muscles.
3. In the presence of calcium ions and energy from ATP, actin and myosin interact forming actomyosin which causes contraction of muscles.
4. During muscle contraction conversion of pyruvic acid to lactic acid proceeds anaerobically.
5. Lactic acid is transported by blood to liver where it is converted to glycogen.
6. Chemical energy is changed into mechanical energy during muscle contraction.
7. The contraction of muscles of shortest duration is seen in eye lids. Shivering in cold is a method for production of heat by muscle contraction.