Has it ever crossed your mind to ask how come you are able to act or move perfectly? When you run fast you feel your heart is racing, when you get excited the same thing happens. If ever you get in trouble you can run and move so nimbly that even you yourself are amazed with what you can do. These are all possible due to the magnificent command issued by the brain and its trusted sidekick, the neurons. Today we will tackle all about the nervous tissue.Credit: http://commons.wikimedia.org/wiki/File:Adult_polyglucosan_body_disease_histopathology.jpg
The Nervous Tissue
You may have knowledge regarding the muscle tissue and the other 2 types of tissues in the body. The fourth type of tissue is the nervous tissue which consists of the nerve cells or the neurons and the neuroglia. The neurons serve as the basic unit of the nervous tissues and are responsible in generating and conducting electrochemical signals a cellular process known as the neuronal process. The neuralgia on the other hand plays as the support character for the neuron. Its ability to conduct signals given off by the neurons makes them an inseparable pair. What’s interesting is when we are born, we already have a fix number of neurons and they are incapable of regeneration so when they are damaged or injured, there is no possible way to regain them or make new ones.Credit: http://www.solarnavigator.net/human_brain.htm
Types of Neurons
Basing on the number of “poles” or processes, neurons are categorized into three namely: Unipolar, bipolar and multipolar. Poles that are arborized or highly branched without covering are called dendrites. The long, slender and minimally branched poles are called axons. The three named variety of neurons differ in size and in shape. Unipolar neurons, as the name suggests, has one process and splits near the cell body into peripheral and central processes. The poles conduct impulse within the same direction and each is referred to as an axon. Bipolar neurons, by the name have two poles referred to as axons which also conduct impulses in the same direction. Multipolar neurons, on the other hand have more than two poles.Credit: http://www.wiredtowinthemovie.com/mindtrip_xml.html
To say it simply, axons are the ones responsible in carrying signals away from the cell or the point of origin. Most axons are protected by a covering of insulating phospholipids or myelin sheath that also enhances signal conduction. The layers of myelin sheath can be as many as 200 layers. The oligodendrocytes produce the myelin sheath aided by the Schwann cells. Both the central nervous system and the peripheral nervous system play a role in this process. Interestingly though, all axons of the peripheral nervous system are covered by a sheath of Schwann cells but not necessarily of myelin sheath. The Schwann cells are also attributed in the regeneration of axons, not the entire neuron, of the peripheral nervous system.Credit: http://commons.wikimedia.org/wiki/File:Neuroglia.png
Neuroglia or referred to sometimes as the Schwann cells are present in both central and peripheral nervous system. Their key play happens in the attachment to both neurons and blood vessels that offer support with regards to metabolic, physical and nutrition. It is also believed that the neuroglia plays a role in the blood-brain barrier.
Somehow the phrase electrifying energy holds some ground of truth inside our body. Thanks to these nervous tissues we are able to sense, feel and live the way we are living…able to send and receive impulses and adapting to circumstances. Knowing that the neurons do not regenerate, then the key to survival lies in our hands.