Skeletal Muscles in Human

Skeletal muscle is a muscle tissue that is attached to the bones and is involved in the functioning of different parts of the body. These muscles are also called voluntary muscles as they come under the control of the central nervous system in the body.

Structure Of Skeletal Muscle

Skeletal Muscles
They are attached to the bones by elastic tissue or collagen fibres called tendons. These tendons are comprised of connective tissues. The skeletal muscles consist of a bundle of muscle fibres namely fascicule. These fascicules are cylindrical in shape as shown in the figure. These muscle fibres are surrounded by blood vessels and several layers of other tissues enclosing them.

Each muscle fibre is lined by a plasma membrane namely sarcolemma reticulum. It encloses a cytoplasm called sarcoplasm which has the endoplasmic reticulum. The fascicule is enclosed by perimysium and the endomysium is the connective tissue that encloses the muscle fibres.

Functions of Skeletal Muscle

  • They maintain body posture and regulates body temperature.
  • It connects to and controls the motions of the skeleton. And responsible for performing muscular involuntary movements.
  • It is responsible for body movements such as breathing, extending the arm, typing, writing, etc.
  • It is responsible for the erect posture of the body. The sartorius muscles in the thighs are responsible for body movement.
  • They protect the internal organs and tissues from any injury.
  • These also support the entry and exit points of the body.

Properties Of Skeletal Muscle

  • 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 their 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

  • Red Muscles: They are high amounts in the human body. These muscles are smaller in diameter and have a large number of mitochondria in them. Myoglobin stores oxygen, which is used by the mitochondria for the synthesis of ATP. Red muscles have a large number of blood capillaries in them.
  • White Muscles: White muscles are bigger in diameter and have a small amount of myoglobin in them. They also have fewer mitochondria in them.

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