The Human Nervous System
The Human nervous system is the most complex and vital part of our body. It is a biological information highway. It manages us-our thoughts, feelings, and bodily functions. It is also an important factor in medical science. The studies of the nervous system helped lower death rates from heart disease, stroke, etc. The nervous system is a network of nerve cells called neurons that sends information to the brain. Neurons live both in and outside the central nervous system. Understanding how the neurons work is essential to understanding the nervous system.
Our nervous system is made of Central Nervous System and Peripheral Nervous System. Central Nervous System is the area where the processing takes place and Peripheral Nervous System detects and sends electrical impulses that are used in the nervous system. Both the Central and Peripheral Nervous System is made of nerve cells or neurons.
Neurons process and transmit cellular signals. They are specialized to conduct electrochemical impulses called nerve impulses or action potentials. They can be of various shape, size, and properties given the functions performed by them. Neuron basically consists of three parts – the soma or cell body, the axon, and the dendrites. The Cell Body houses nucleus as well as other organelles like endoplasmic reticulum etc. Most of the protein synthesis occurs here. Axons grow out of the cell body. They are also called Nerve Fibers. The axon carries nerve signals away from the soma or cell body. All neurons outside the central nervous system connect through axons. Axons can be as long as one meter. Many axons are covered with the myelin sheath, a glistening fatty sheath. It is the greatly-expanded plasma membrane of an accessory cell, the Schwann cell. Schwann cells are spaced at regular intervals along the axon. Their plasma membrane is wrapped around the axon forming the myelin sheath. The place where the sheath of one Schwann cell meets that of the...
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