Muscles and Its Types

Muscles are bundles of fibres that can contract and relax as required. The muscular system helps our body move and carry out essential functions. Different muscles work either voluntarily (under our control) or involuntarily (without our control). Tendons connect muscles to bones, and when they contract, they move our bones at the joints. We use muscles for various movements like talking, laughing, walking, jumping, throwing, etc.

Types of Muscle	Description	Example	Movement	Function
Skeletal Muscles	Attached to bones allows us to do actions like walking, lifting, or eating	Muscles in the arms and legs	Voluntary (under our control)	Give shape to the body and help perform voluntary movements
Cardiac Muscles	Found only in the heart, it contracts and relaxes continuously to keep blood pumping.	Heart muscles	Involuntary (automatic)	Keep the heart beating about 70 times per minute
Smooth Muscles	Present in internal organs such as the stomach, intestines, blood vessels, and uterus	Stomach, intestines, blood vessels	Involuntary and slow	Perform vital processes like digestion, circulation, and breathing

 

Muscles in the human body

Activity: To observe how muscles in the arm contract and relax during movement.

• Hold your arm straight at the elbow (180°).
• Bend the arm at the elbow to 90°.
• Touch your shoulder with the fingers of the same arm.
• Notice which muscles contract and which relax during each movement.

During these movements:

• The biceps (front upper arm) muscle contracts when the arm bends.
• The triceps (back upper arm) muscle relaxes.
• The triceps contract when the arm is straightened, and the biceps relax.
• Muscles always work in pairs: one group contracts while the other relaxes to enable smooth movement. This coordinated action allows us to perform various body functions effectively.