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

How has the earth changed since it was formed, How has the earth changed si...

How has the earth changed since it was formed? Ans) The earth has changed particularly since it was formed. Earth was a ball of rock that was strike and changed by loads of imp

Social and economic impact of modern communication, Social and economic imp...

Social and economic impact of modern communication technology: Quite obviously a society which will utilise advanced communication technology in  the ways mentioned above, woul

Minerals, Minerals: Our bones and teeth contain large amounts of calc...

Minerals: Our bones and teeth contain large amounts of calcium. An adult has a total of about 1 kg of calcium and a baby has about 30g in their bones. So, during the period o

Career query, Hello sir, This is pradeep. I have completed M.Sc Biochemist...

Hello sir, This is pradeep. I have completed M.Sc Biochemistry since then i worked as a chemist in quality control department in pharmaceutical and cosmetic companies. I have co

What is pedology, What is Pedology Pedology is concerned with the study...

What is Pedology Pedology is concerned with the study of the composition, distribution and formation of soils as it occurs in nature.  On the other hand edaphology is the study

Define platelets, Define Platelets Blood platelets, the third blood cel...

Define Platelets Blood platelets, the third blood cells are the smallest formed by the pinching of a very large bone marrow cell called megakaryocyte. Platelets literally mean

Interpersonal relations, Interpersonal Relations Mr. X relates easily...

Interpersonal Relations Mr. X relates easily to others and describes himself in positive terms (Ho=38). He believes that others can be trusted and that they have his best int

Define the parietal area of the cerebrum, Define the parietal area of the C...

Define the parietal area of the Cerebrum The parietal area, as you can see in the Figure, lies behind the post central area and includes greater part of parietal lobes of the c

Name the primary minerals present in an igneous rock, a)  Name the primary...

a)  Name the primary minerals present in an  igneous rock.  a )  Quartz (SiO2), feldspars, amphiboles, pyroxenes and micas are the most common primary minerals in igneous  rock

Define nerve cell, Define Nerve Cell The basic unit of the nervous syst...

Define Nerve Cell The basic unit of the nervous system as studied above, is the individual nerve cell - the neuron. The nerve cells operate by generating electrical signals and

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