Classification Of Muscles Notes

There are more than 600 muscles in our body. Muscles perform many useful functions and help us in doing everything in day-to-day life. Muscles are classified by three different methods based on different factors:

1. Depending upon the presence or absence of Voluntary muscle is the muscle that is controlled by the striations
2. Depending upon the control
3. Depending upon the function.

Read And Learn More: Medical Physiology Notes

Depending Upon Striations

Depending upon the presence or absence of the cross striations, the muscles are divided into two groups:

1. Striated muscle
2. Nonstriated muscle.

1. Striated Muscle: Striated muscle is the muscle which has a large number of cross striations (transverse lines). Skeletal muscle and cardiac muscle belong to this category.

2. Nonstriated Muscle: The muscle which does not have cross striations is called nonstriated muscle. It is also called plain muscle or smooth muscle. It is found in the wall of the visceral organs.

Depending Upon The Control

Depending upon the control, the muscles are classified into two types:

1. Voluntary muscle
2. Involuntary muscle.

1. Voluntary Muscle: The muscle is the muscle that is Controlled By The will. Skeletal muscles are voluntary muscles. These muscles are innervated by somatic nerves.

2. Involuntary Muscle: The muscle that cannot be controlled by the will is called involuntary muscle. Cardiac muscle and smooth muscle are involuntary muscles. These muscles are innervated by autonomic nerves.

Depending Upon The Situation

The muscles are classified into three types depending on the situation:

1. Skeletal muscle
2. Cardiac muscle
3. Smooth muscle.

The features of these muscles are given in.

1. Skeletal Muscle:

• Skeletal muscle is situated in association with bones, forming the skeletal system. The skeletal muscles form 40-50% of body mass and are voluntary and striated. These muscles are supplied by somatic nerves.
• The fibers of the skeletal muscles are arranged in parallel. In most of the skeletal muscles, the muscle fibers are attached to tendons on either end. The skeletal muscles are anchored to the bones by the tendons.

2. Cardiac Muscle: Cardiac muscle forms the musculature of the heart. These muscles are striated and involuntary. Cardiac muscles are supplied by autonomic nerve fibers.

3. Smooth Muscle: Smooth muscle is situated in association with viscera. It is also called visceral muscle. It is different from skeletal and cardiac muscles because of the absence of cross striations; hence the name smooth muscle. Smooth muscle is supplied by autonomic nerve fibers. Smooth muscles form the main contractile units of the wall of the various visceral organs.