Muscular System (Part-II)

Introduction: Muscle is one type of tissue among four different tissues. Muscle is a specialised type of tissue and it originating from mesoderm. Muscles alone contribute around 40 to 50 percent body weight of the human. Excitability, contractility, elasticity and extensibility are the special characteristic nature of the muscle cells.
Based on their location, muscles are classified into three categories:

1. Skeletal muscles,
2. Visceral muscles and
3. Cardiac muscles.

Skeletal Muscles: Muscles which are associated with skeletal components are known as skeletal muscles. Microscopically their appearance is look like striped. Hence they are also called as striated muscles. These muscle activities are regulated voluntarily by the nervous system. The principle action of skeletal muscle is locomotion and it can modulate body shape.

Visceral muscles: Visceral muscle present in inner walls of hollow visceral organs of the body. Example includes, alimentary canal, reproductive tract, etc. Unlike skeletal muscle, they are smooth in appearance. They are involuntary in nature so nervous system cannot control voluntarily. Visceral muscle involves in food transport in digestive tract and gamete transport through the genital tract.

Cardiac muscles: Heart consists of cardiac muscles in which cells assemble in a branching pattern. Like skeletal muscles, they are also striated. Activity wise, they are involuntary in nature thus nervous system cannot control the cardiac muscles directly. The different between these muscle forms is given in Table 16.1.