The three main types of muscle tissue are skeletal, smooth, and cardiac. The dark stripes, or bands, that are visible in muscle under the microscope are referred to as striations, and they are responsible for the movement of muscles.
Skeletal muscle is the muscle that can be seen and felt on the bodyùthe muscles that are developed during a workout. This is the muscle in the arms, legs, back, and abdomen, among other sites. Skeletal muscle attaches to the skeleton in pairs; one muscle moves the bone in one direction, and the other muscle moves it back in the opposite direction. These muscles contract voluntarily when the person thinks about contracting them and they receive a signal from the nervous system to follow through on the thought. There are two types of muscle contractions, a single contractionùcalled a twitchùand a long, sustained contractionùcalled a tetanus. (Freudenrich).
Smooth muscle is the type that is found in the digestive tract, blood vessels, bladder, airways, and uterus. It has the ability to stretch and maintain its tension for long periods of time. This type of muscle contracts involuntarily, meaning that the person does not have to think about contracting them; they are automatically controlled by the nervous system without any conscious thought or intervention on the part of the person. (Freudenrich).
Cardiac muscle is found only in the heart. It is unique for its endurance and consistency, but it is similar to a combination between skeletal and smooth muscle. It is only capable of stretching in a limited way, like smooth muscle does, but it contracts with the same type of force as a skeletal muscle. It is a twitch muscle only, and it contracts involuntarily. (Freudenrich).
Using skeletal muscles as an example of how muscle cells are constructed, they are made up of two main components. The first component is a sarcolemma, an outer wrapper that surrounds the second compo
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