Define specific defence mechanism, Science

Assignment Help:

Define Specific Defence Mechanism

In the section on white blood cells, we learnt that whenever a germ or infection enters our body, the WBCs snap to attention and destroy the culprit. How does a white blood cell know what to attack and what to leave alone? Why doesn't a white blood cell attack every cell in the body? The answer to these questions lies in the discussion below.

The specific defence mechanism provides protection against specific foreign materials. The important characteristic is that its cells (lymphocytes) have an ability to recognize body's own cells and macro molecules (self) from those which are foreign invaders (non self ). It tolerates the 'self' but destroys the 'non self'. The lymphocytes bearing receptor is specific for self i.e. molecules already present in the body, are either made non-functional or destroyed by programmed cell-death known as apoptosis. The lymphocytes that react to non self i.e. foreign molecules are left to function in immune responses.

So, you realize that there is a system built into all of the cells in our body that marks the cells in our body as "self '. Anything that the immune system finds that does not have these markings (or that has the wrong markings) is definitely "not self" and is therefore a fair game. This system is called the Major Histocompatibility Complex (MHC).


Related Discussions:- Define specific defence mechanism

Explain primary processing of oilseeds and pulse products, Pulse products: ...

Pulse products: The important processed pulse products are puffed chickpea and pea,  besan, papads, pulse-based weaning foods, quick cooking dhals, and canned dry peas   Oils

Expanding universe, The Expanding Universe: Hubble's observations had...

The Expanding Universe: Hubble's observations had proved  the existence of  galaxies. After mapping as many galaxies as could be seen by  the telescopes then'available, he tu

Explain the discovery of cell, Explain the Discovery of Cell Let us stu...

Explain the Discovery of Cell Let us study here about the scientists who played a pioneer role in discovering the basic component of any living organism -the cell. Robert Hooke

Plants.., what is the photosynthesis?

what is the photosynthesis?

Aids, AIDS: You have learnt about infectious diseases. For centuries, d...

AIDS: You have learnt about infectious diseases. For centuries, death from infectious diseases was common and whole populations were often affected.  One of the remarkable achi

Explain oxygen dissociation curve, Explain Oxygen Dissociation Curve Wh...

Explain Oxygen Dissociation Curve While different partial pressures of oxygen are  plotted against the amount of  oxyhaemoglobin created or  dissociated, the sigmoid  curve  is

Define ligases, Ligases (synthetases) These enzymes (code EC 6) catal...

Ligases (synthetases) These enzymes (code EC 6) catalyze the linkage of two molecules coupled with the hydrolytic breakdown of a pyrophosphate bond  in ATP or an analogous co

Rh blood group, what is diffrence between rh positive and rh negative

what is diffrence between rh positive and rh negative

Explain main factors that influence mass movement, Discuss main factors tha...

Discuss main factors that influence mass movements. Ans) Things as if climate and food availability will make a big dissimilarity if it is too cold, too dry then people will re

Immune mechanisms - physiology of growth and development, Explain the Immun...

Explain the Immune mechanisms - Physiology of Growth and Development The immune system starts functioning in a baby through the inherited antibody (Ab) of the mother. But these

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd