Skeletal Muscle

skeletal muscle diagramSkeletal muscle is one of three types of muscles in the human body – the others are muscles of the body and muscles of the heart. This lesson explains skeletal muscles, their definition, anatomy, properties, functions and types in a simple and comprehensive way.

Skeletal muscle is a muscle that attaches to a bone that is involved in the functioning of various parts of the body. These muscles are under the control of the nervous system in the body and are also called voluntary muscles.

Structure Of Skeletal Muscle

The structure of skeletal muscle is shown below:

The muscle is attached to the bones by elastic or collagen fibers called tendons. These blood vessels are made up of connective tissue. Skeletal muscle consists of a group of fascicles. These pieces are cylindrical as shown in the figure. These muscles are surrounded by blood vessels and other tissues.

Each muscle fiber is covered by a layer of plasma, called the sarcolemma reticulum. It consists of endoplasmic reticulum enclosing a part of cytoplasm called sarcoplasm.

Muscle fibers are made up of myofibrils, which are made up of two main proteins, actin and myosin. The fasciculus is covered by the perimysium and the endomysium is the connective tissue enclosing the muscle fiber.

Properties Of Skeletal Muscle

The skeletal muscles have the following properties:

  • Extensibility: It is the ability of the muscles to extend when it is stretched.
  • Elasticity: It is the ability of the muscles to return to its original structure when released.
  • Excitability: It is the ability of the muscle to respond to a stimulus.
  • Contractility: It is the ability of a muscle to contract when in contact with a stimulus.

Types Of Skeletal Muscle

There are two types of skeletal muscles named as red and white muscles-

  • Red Muscles
  • White Muscles
Red Muscles

Red muscles are caused by myoglobin, the red pigment found in abundance in the human body. These muscles are smaller in diameter and contain more mitochondria. Myoglobin stores oxygen, used by mitochondria to produce ATP. Red muscles contain many red blood vessels.

White Muscles

Unlike red muscle, white muscle is larger in diameter and contains less myoglobin. They also have a low number of mitochondria.

Functions Of Skeletal Muscle

Following are the important skeletal muscle function:

  • Skeletal muscles are responsible for body movements such as typing, breathing, stretching, typing, etc. The muscles contract and then the tendons in the bones contract and cause movement.
  • Body posture is maintained by skeletal muscles. The gluteal muscle is responsible for the upright posture of the body. The sartorial muscles in the thighs are responsible for body movement.
  • Skeletal muscles protect the internal organs and tissues from any injury and also provide support for these soft tissues and tissues.
  • These also support the entry and exit points of the body. Sphincter muscles are present around the anus, mouth and urethra. These muscles contract to reduce the size of the openings, making it easier to swallow food, urinate and urinate.
  • Skeletal muscle also regulates body temperature. After a strenuous workout, the body feels warm. This occurs due to skeletal muscle contraction, which converts energy into heat.

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