Human has more than 600 skeletal muscles which give him the ability to move - walking, running, etc.; to set in motion some parts of the body; to ma

Skeletal muscle structure

Human has more than 600 skeletal muscles which give him the ability to move — walking, running, etc.; to set in motion some parts of the body; to maintain its balance and a certain position. They are a place where the glycogen accumulates. Skeletal muscles have specific receptors that allow controlling the position of the body. The main physiological properties of muscle are the excitability and contractility.

Skeletal muscles make up 30-40% of the adult human body weight (in athletes — nearly 50%). They cover the human skeleton completely; only in few areas bones are placed directly under the skin.

Skeletal muscles contain a large number of nerves and blood vessels. Each skeletal muscle is attached to the two ends of the periosteum (diagram 33, 35). The initial, fixed muscle part is called a head, and the opposite, thrown over the joint to another bone — a tail; between them is located a thickened part of the muscle — its body, or abdomen. There are muscles with one head — simple. If there are two of them — they are called biceps, three — triceps. Both ends of the muscles transform into a strong and elastic connective tissue that forms the tendon. With the help of the latter, muscles are attached to the periosteum. Contraction of skeletal muscles is regulated by cortex via somatic nervous system. Taken from http://worldofschool.org

Diagram 33. Different sections of skeletal muscle: 1 — head; 2 — abdomen; 3 — tail
Diagram 35. The place of the tail muscle attachment (1) to the second bone periosteum; lever development (2)
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Questions:
  • Describe the importance of skeletal muscles in the human body.

  • Explain the features of the skeletal muscle anatomical structure that are associated with their function.

  • What features of the human muscular system are associated with bipedalism?