Immunity, innate immunity - Human Health and Diseases, Biology, Class 12 Video Lecture

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we will talk about immunity so let us
see what does immunity now immunity is
the ability of an organism to fight the
disease-causing organisms so by now we
saw that there are a set of organisms
which are capable of causing disease and
they are what pathogens but inside our
body also we have a mechanism which
fights these disease-causing organisms
in order to protect our body so that is
known as immunity and with this entire
system of our body which contains all
the different organs which together
fight the infection that has got the
immune system so now we are going to
talk about that now when we talk about
immunity you just think of it in this
way then I suppose when you have a big
house so all your valuables and
everything is present inside this house
and you want to protect them so how do
you protect them by keeping security
guards outside your house so what does
the purpose or what is the job of these
security guards to protect your house so
what is the house house is our body and
we want to protect our body from any
disease causing organisms and who gives
immunity to our body the immune system
there are several organs which part
which are part of the immune system and
this immune system acts as the security
guards okay and protection is even
against whom like in this case the
protection is even against the thief so
this thief is nothing but that
disease-causing organisms that is the
pathogens so immunity is that ability
now for Organa's and so for human beings
who have got a very strong immune system
they will not and easily and act by
means microorganisms by those who have a
very weak immune system they will be
more prone to common cold or fever or
all these things because their immune
system is not strong enough so add the
stronger is the security system in your
house the lesser chance is that a theft
can happen in your house but the weaker
the security system the more chances
that a theft will happen so that very
similarly it is true for our immune
system as well now when we talk about
the types of immunity there are broadly
two types of immunity that is innate
immunity and acquired immunity so what
do we mean by each of them now innate
the word imminent means inborn so this
is that type of immunity which is
present inside our body by birth so it
is inborn mmunity so when a small baby
is born this that baby also has some
immunity inside its body that even if
some small Jones or something attacks it
the body will be able to able to fight
against it so that type of immunity is
called
inborn immunity the other type of
immunity is immunity which is acquired
afterward so how is immunity acquired so
when you talk about immunity being
acquired it means that some sort of
medicines I mean they are not exactly my
distance but some sort of substances are
introduced inside your body which
provides immunity to your body now water
those substances how they provide
immunity we will discuss that very soon
so but the concept is in acquired
immunity it is not present by birth it
is it comes inside the body only later
in life but innate immunity in something
which is present by word now innate
immunity is nonspecific defense so this
type of immunity is not against a
specific pathogen so it is in general
immunity so that it can protect against
all sort of organisms or objects which
are poor
see - Gordon but when you talk about
that wired immunity it is a pathogen
specific defense that means acquired
immunity may be immunity is provided to
an organism against a specific pathogen
so for example in case of typhoid time
void is caused by a specific pathogen
that the Salmonella typhi similarly a
common cold is caused by a virus so if
your body has acquired immunity for
Salmonella typhi that means typhoid will
not happen because that can be formed by
the immune system but that doesn't mean
that it can also fight the viruses so
acquired immunity is always against a
specific pathogen and it is not it is
not that it can fight with any type of
pathogen but in case of innate immunity
it is a nonspecific defense it is not
against the specific defense it can only
protect the body from all common sort of
infections but it is not very strong it
has to develop as the baby grows so
first we will talk about innate immunity
now innate immunity there are different
barriers which stop entry of unwanted
foreign matter inside the body now what
are these barriers which we are talking
about now it is not necessary that they
have to be physical barriers there are
many different types of barriers so let
us quickly have a look at what are the
barriers which stop foreign particles to
enter inside our body first candidly is
a physical barrier next is physiological
Banyon cellular barrier and finally
cytokine barrier so these are the four
types of barriers which together gives
innate immunity or inborn immunity to an
organism so let us discuss about each of
these types of barriers and let us see
how they stop the entry of unwanted
substances into the bottom so we will
first talk about the physical barrier
physical barriers
which physically stops the entry of
foreign materials so physical barrier is
a skin so skin is something which is
present in our body by birth so we do
not get in after we are born later so we
are born with the skin so skin acts as a
physical barrier it stops entry of many
substances inside our body lining of
respiratory gastrointestinal and euro
genital tract so all these tracks they
have a lining of small small cells which
actually act as a barrier to foreign
materials for example you would have
observed that when we breathe in inside
our nostrils we have small hair like
structures so what do they do they
prevent the entry of dust or dirt
particles inside the nasal passage so
that is how it that also acts as a
physical barrier physiological bagging
and what are physiological barriers
these are not physical values they are
not basically substances but they are
certain things which are released by
some part of our body for example
stomach acid the medium inside the
stomach is acidic due to the presence of
hydrochloric acid now this term acid
also prevents now the microorganisms or
pathogens to be present inside our body
that is because the microorganisms
cannot survive in an acidic medium so
that acts as a physiological bag mouth
saliva so saliva also is a watery fluid
which is secreted inside the oral cavity
now this saliva also has a specific pH
which is not very suitable for the
survival of many pathogens tears the
tears the watery substance which comes
out of our eyes and the tears also
contain many chemicals which do not
favor or which prevents the growth of
microorganisms so that means it prevents
any sort of infection
our eyes so stomach acids that I find
tears and examples of physiological
barriers the third one is the cellular
baguette that means there are certain
cells which itself act as barriers now
some of the cells are here besides
monocytes lymphocytes macrophages these
are some of the cells which help to
fight infections so these cells in
itself they act as barriers start to
iron banner water cytokine these are the
substances which are secreted by certain
cells of the immune system which infect
other cells now the immune system will
have certain orbits and they release
some substances but these substances
will have an impact on other cells so
these are both cytokine now examples are
interference which prevent viral
infection in lawn infected cells so it
doesn't allow the virus to infect the
corner cells so that is how it acts as a
barrier so these are the different types
of value at all these things are present
inside our body by birth so the spelling
talked about you besides all those sites
lymphocytes or you talked about skin or
hazel come into your gastrointestinal
tract lining so all these things are
present in our body by birth and that is
where they all form a part of innate
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