Types of Muscles

Muscles

About 35% of a person's bodyweight is attributed to muscle. As with all mammals, the human body's muscle tissue is categorized into three branches.

A. Cardiac muscles are only found in the heart. They make short rhythmic contractions and are controlled involuntarily. While nerves from the autonomic nervous system are present alongside cardiac muscles it has been noted that the autonomic impulses only alter the rate of contractions. Science has not yet proven what exactly causes the continuos rhythmic contractions. Cardiac muscles require constant supply of oxygen, and would quickly die (in a case of heart attack for example) if blood rich on oxygen fails to be delivered to them.

B. Smooth muscles are also considered visceral (involuntarily controlled) and are used in your skin, digestive system, excretory system, bladder, major blood vessels, airways and reproductive system. These muscles are capable of tetanus (prolonged) as well as twitch contractions.

C. Skeletal (striated) muscles are the only type that can be voluntarily controlled. They are attached to the skeleton (by a tissue called tendon) in pairs, so that they can move the bone in two opposite directions. Deep fascia is an irregular connective tissue, which wraps the muscles into functional and specific groups filling the space between them. Blood supply and nerves servicing the muscles all pass through the deep fascia. An outer layer of connective tissue (epimysium) surrounds skeletal muscles defining their shape and protecting them.