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Saturday, December 25, 2010

Three types of muscles - Lesson 229

In this post we will learn about the Muscles and its types.
There are three types of muscles in the body which are briefly explained below. They are
1. Smooth muscles:- These muscles are also called involuntary or visceral muscles, are those muscle fibers that move internal organs such as the digestive tract, blood vessels, and secretory ducts leading from glands. These muscles are controlled by the autonomic nervous system. They are so called smooth because they have no dark and light fibrils in their cytoplasm. Skeletal muscle fibers are arranged in bundles, while smooth muscle forms sheets of fibers as it wraps around tubes and vessels.

2. Striated muscles:- These muscles are also called voluntary or skeletal muscles which are the muscle fibers that move all bones as well as the face and eyes. We have deep or conscious control over the muscles through the central and peripheral nervous system. The fibers also called cells known Striated muscle fibers have a pattern or way of dark and light bands, or fibrils, in their cytoplasm. Fibrous tissue that envelops and separates muscles is called fascia, which contains the muscles such as blood, lymph, and nerve supply.

3. Cardiac muscle:- This muscle is striated in appearance but like smooth muscle in its auction. Its movement cannot be consciously controlled. The fibers of cardiac muscle are branching fibers and are found in the heart.

Skeletal Muscles actions:- Skeletal or striated muscles which are over 400 in the  human body are the muscles that move bones. When a muscle contracts, one of the bones to which it is joined remains virtually stationary as a result of other muscles that hold it in place. The point of attachment of the muscle to the stationary bone is called the origin or beginning of that muscle. Whenever the muscle contracts, another bone to which it is attached does move. The point of junction of the muscle to the bone that moves is called the insertion of the muscle. The origin of the biceps is at the scapula, and its insertion is at the radius. Tendons are the connective tissue bands that connect muscles to the bones that they move.

Muscles can perform a variety of actions.

In the next post we will come across some of the meanings of the actions and vocabulary terms.

To go to the prior lesson from here please click the link below.

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