![]() A neuron can send nerve-currents from one part of the organism to another. Both cell-bodies and nerve-fibres possess irritability and conductivity. The neurons consist of the cell-bodies and nerve-fibres. A nerve-impulse or current is an electro-chemical wave which can move a nerve-centre or a muscle to action. When a motor neuron in the cord or the brain is stimulated, it quickly transmits a nerve- impulse to a muscle which makes a movement. When a sensory nerve is stimulated, it quickly transmits a nerve-impulse to the spinal cord or the brain. It has another membranous sheath called the neurilemma. It has a relatively thick covering called the myelin or medullary sheath. It constitutes the true nerve and carries the nerve-impulse from one point to another. The central strand is called the axis cylinder. The fully developed nerve-fibres have a complex structure. So it obstructs the flow of nervous energy. But there is a greater delay in the passage of nerve-currents through the synapse. There is inhibition of nerve-currents in the synapse. They are not conducted from the latter to the former. Nerve-currents are conducted from the ends of the sensory axon to the dendrites of the motor cells. The dendrite in a synapse is a receiving organ, while the axon end-brush is a stimulating organ, and not a receiving organ.Īt the synapse the axon end-brush of one neuron stimulates the dendrites of another neuron, but there is no continuity between the two processes. Here the axon of one neuron breaks up into an end-brush of fine branches, which interlace with the dendrites of the other neuron. The junction of two neurons is called the ‘synapse’. The axon looks like a long slender thread without branches and ends in an end-brush. The dendrites look like the branches of a tree. They are the elementary structural units, which are separate and distinct.Įach neuron consists of the nerve-cell and dendrites and axon. There are millions of neurons in the nervous system. The grey matter of the brain is composed of cell-bodies and dendrites, while the white Matter is made tip of the axons. An axon is long while a dendrite is short. An axon has a myelin or medullary sheath which insulates it. A dendrite transmits the nerve current towards the cell-body. An axon transmits the nerve current away from the cell-body. The other is the sending-type, and is called ‘axon’. One is the receiving type and is called ‘dendrite’. ![]() ![]() ![]() Two types of branches are connected with each nerve- cell. It has a cell-body containing a thick substance called ‘nucleus’, and often within this substance nucleus smaller bodies called nucleoli, and its branches or filaments radiating from it. It has a tough coat called cell-wall, and contains a white jellylike called ‘protoplasm’. Its filaments are really a part of the cell. A nerve-cell with all its filaments is called a neuron. After reading this article you will learn about:- 1. ![]()
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