Functional unit of the nervous system-neuron, Science

Functional unit of the nervous system-neuron:

The human brain is composed of more than one hundred billion (100,000,000,000  or 1011) cells called  'neurons'. This number which  is comparable  to the number of stars  in the Milky Way, gives us an idea about the size of the neurons also  -  because 10"  of  them fit in a space which slightly more than a litre of water can occupy. Since these neurons are the functional units of the whole nervous system, let us become familiar with some of their basic features. You can see some typical neurons in Fig.

Neurons can be categorised  into the following kinds according to their functions : 

a) Motor neurons  :  send signals from the nervous system to muscles and glands.

b)  Sensory neurons :  carry signals from the receptor cells in  sense organs in the body to the nervous System. For example, signals generated by  touch or smell or hearing etc. 

c)  lnter neurons  or association neurons :  process the sensory  information received from other neurons,  and convey messages. For example, when an  insect bites, the fingers are given a command  to~cratch  at ,  that point. Most of  the brain's neurons fall in this category. 

The neurons are specialised to carry iqformation from one part of the body to another. These messages are referted to as nerve  impulses. The nerve impulse occurs in response to some. stimulus  or  event which excites  them. Notice in fig that in every neuron,  fhe portion of the cell with the nucleus is called the cell body.

234_neuron.png

Posted Date: 9/28/2012 8:35:44 AM | Location : United States







Related Discussions:- Functional unit of the nervous system-neuron, Assignment Help, Ask Question on Functional unit of the nervous system-neuron, Get Answer, Expert's Help, Functional unit of the nervous system-neuron Discussions

Write discussion on Functional unit of the nervous system-neuron
Your posts are moderated
Related Questions
how to prevent skin problems?

explain what ausubel''s theory say about learning

How Complement System Helps To Handle Microbial Invasion 1)  Some components of a complement system coat microorganisms. These organisms with such a coat can be easily phagocyt

QUESTION 1 (a) How did psychology emerge as a separate scientific field? (b) Elaborate on any two schools of Psychology QUESTION 2 Elaborate on the correlational met

Explain Myocurdial Ischemia and Infarction Myocardial ischemia (insufficient blood flow) or myocardial infarction (death of heart cells) reduces myocardial contractile force an

Explain the Functions of Parathyroid Gland The main function of the parathyroid gland is to regulate the calcium levels in our body so that the nervous and muscular functions (

Life in the Oceans: Oceans are known as the largest and the thickest ecosystem. Tiny plants and animals exist in it, in  immense numbers. A cubic meter of sea water may contain

Define General Hormones General hormones, on the other hand, are emptied into the blood by specific endocrine glands and then flow throughout the entire circulation to affect c

Scientific and Technical Achievements of Bronze Age:   The major technical advance  that accompanied the rise of cities was the discovery and use of metals, particularly coppe