The muscular system

• The unit of structure of the muscular system is the muscle, made of muscular tissue.
• There are about 620 or more muscles in man (flesh).
• Muscles allow mechanical movement and locomotion.

General characteristic of muscle cells: they are elongated (thread-like) and able to contract and relax.

Functions of muscles:

1. Locomotion (moving from one place to another) and all body movements.
2. Pushing blood in the circulation and maintaining blood pressure by the contraction of the involuntary (smooth) muscles in the walls of blood vessels (and the cardiac muscle of the heart).
3. Movement of food in the alimentary canal (peristalsis), breathing movements (diaphragm and intercostal muscles), maintaining posture, producing body heat, protecting internal organs.

Types of muscle:

Most body muscles are under the control of the will and are called voluntary (skeletal, striated) muscles; the others are involuntary.