Describe in detall about Voluntary muscles and voluntary movements.
- There are numerous voluntary muscles in human body. These are also known as skeletal or striated muscles.
- The muscle movement which are under the control of ones will are called valutory movements.
- Striated muscles are formed by the bundles of actin and myosin myofibrils.
- Striated muscles are fusiform and tapering at both the ends known as tendon.
- 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.
- On contraction, voluntary muscles become bulged and thick and on relaxation becomne thin and elongated. Contraction of voluntary muscles require a threshold of stimulus.
- These muscles can pul the bones but cannot push the bones away.
- 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.
- 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).