muscle

Muscle is a type of tissue that can contract and relax. This allows muscles to move bones and other parts of the body. Muscles are made up of long, thin cells that are bundled together. When these cells contract, they shorten and pull on the bones or other parts of the body. This is how muscles move.

There are three types of muscles in the human body: skeletal muscles, smooth muscles, and cardiac muscles.

Skeletal muscles are the muscles that we can control consciously. They are attached to bones and allow us to move our bodies.

Smooth muscles are the muscles that we cannot control consciously. They are found in the walls of our organs and blood vessels. They help to move food through our digestive system and blood through our body.

Cardiac muscles are the muscles that make up our heart. They contract and relax rhythmically to pump blood throughout our body.

The bodybuilder flexed his muscles.