Nerves are formed by processes of the nerve cells, which bodies are located in the brain and spinal cord. They are collected in bundles and are cover

Types of nerves

Nerves are formed by processes of the nerve cells, which bodies are located in the brain and spinal cord. They are collected in bundles and are covered with external sheath of connective tissue. Each individual nerve fiber is covered fat-like substance — myelin, which acts as an electrical insulator (diagram 143).

The nerves that carry information from receptors in the central nervous system are called sensitive or afferent. Those that conduct impulses from the central nervous system to the organs and tissues — efferentmotor (innervate muscle tissue) or secretory (innervate glands). Neurons scions of the autonomic nervous system form the vegetative or trophic nerves (provide the metabolic processes in the tissues). There are also mixed nerves that contain both sensory and efferent nerve fibers or other. Taken from http://worldofschool.org

Diagram 143. Diagram of a nerve: 1 — myelin sheath; 2 — nerve fibers; 3 — bundles of nerve fibers; 4 — blood vessels

Constant and even increasing mental load, persistent labor is needed for a person to create new interneuron contacts.

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Questions:
  • Give the definition of "nerves."

  • Give examples of nerve species.

  • What determines the mental development of man?