Describe in detall about Voluntary muscles and voluntary movements

Describe in detall about Voluntary muscles and voluntary movements.

Answer :  

1. There are numerous voluntary muscles in human body. These are also known as skeletal or striated muscles.
2. The muscle movement which are under the control of ones will are called valutory movements.
3. Striated muscles are formed by the bundles of actin and myosin myofibrils.
4. Striated muscles are fusiform and tapering at both the ends known as tendon.
5. These muscles are attached to the bones by tendons hence called skeletal muscles. One end of muscle is attached to a immovable bone known as origin and the other end (tendon) is attached to movable bone called insertion.
6. On contraction, voluntary muscles become bulged and thick and on relaxation becomne thin and elongated. Contraction of voluntary muscles require a threshold of stimulus.
7. These muscles can pul the bones but cannot push the bones away.
8. For normal mOvements and locomotion the muscles are present in a pair of Antagonistic muscles. A pair of muscles which bring opposite movements at the same joint by their Contraction are known as antagonistic muscles. e.g. Flexor and Extensor, Adductor and Abuductor.
9. Such pair of muscles is not present on the same bone whose movement is brought about but are present on other component bones. (Fixed bone).