Central Nervous System

The Central Nervous System (CNS) is the most important unit in an organism as it is the ‘center’ or the hub which instigates information and commands and coordinates and also influences all the other actives within a body. This it is often called as the central processing unit of the body. The CNS mainly comprises of two parts: the brain and spinal cord.

The brain is the most important organ which is divided into three parts:

  1. the forebrain,
  2. midbrain
  3. hindbrain

Thus consuming approximately 30 percent of oxygen.  It interprets information from the five senses in a body along with the internal organ stomach. The CNS sometimes also includes the retina, optic nerves, olfactory epithelium and olfactory nerves as they connect directly with the tissues of the brain without any connecting nerve fibers.  On the other hand, the spinal cord acts as a bridge between the brain and the body. Thus, if the spinal cord is injured or affected, the flow of information will be interrupted.

Central Nervous System

Central Nervous System – Forebrain, Midbrain, and Hindbrain

Cells of the Central Nervous System

There are various cells which act as the major unit to help in the function of the CNS properly out of which neurons and glia are the major ones. These cells are connected to the brain where all the information is stored and enacted.

Neurons

Neurons are the fundamental unit of the brain which is responsible for processing and transmitting information to other nerve cells, glands, and muscles. There are about 100 billion neurons where each neuron consists of a cell body and axon and dendrites create the extensions.

Dendrites

They are the specialized form extensions from the cell body with functions to receive information from various cells and carry that information back to the cell body. Thus dendrites are often known as processes.

 Glial cells

There are basically three different types of glial cells that function to provide the neutrons with metabolism and mechanical supports. These cells are:

  • Astrocytes: They are the collective ‘star’ shaped glial cells in the nervous system which performs various functions from biochemical supporting of the endothelial cells to repair and scan the process of the brain and the spinal cord during injuries.
  • Microglia:  They comprises of about 10 to 15 percent of all the cells in the brain which acts as the resistance cell. Their foremost role is to act as an immune defense and helps in clearing out the dead and dying cells. In the process, they also produce small molecules called cytokines that act as a catalyst in helping the immune system.
  • Oligodendrocytes:  The primary function of Oligodendrocytes in glial cells is to provide a support and wrap around the axons. In order to do this, they produce a fatty substance called myelin sheath which allows the nerve cells to send and receive signals quickly.

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Related Links

Nerves

Neurons

Cell Structure


Practise This Question

Which of the following nutrients are energy sources for the brain?