Describe the structure, location and function of smooth muscles.

Smooth muscles are also known as nonstriated, visceral or involuntary muscles. 

Structure: 

1. These muscles are present in the form of sheets or layers. 

2. Each muscle cell is spindle shaped or fusiform. 

3. The fibres are unbranched and have a single nucleus that is located centrally. 

4. The sarcoplasm contains myofibrils which are made up of the contractile proteins – actin and myosin. 

5. Smooth muscles contain less myosin and more actin. 

6. Striations are absent, hence smooth muscles are also known as non-striated muscles,

7. These muscles are innervated by the autonomous nervous system. 

Location: 

It is found in walls of visceral organs and blood vessels. Therefore, smooth muscles are also known as visceral muscles.

Function: 

Smooth muscles are associated with involuntary movements of the body like peristaltic movement of food through the digestive system.