L18 : Respiration in human beings - Life Processes, Science, Class 10 Video Lecture

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let us now study about the lungs which
are the functional units or which are
the main places where the actual
absorption of oxygen takes place in the
respiratory system so lungs are spongy
elastic organs as you can see here these
are the two lungs which we have in our
body they are spongy and elastic elastic
means they can they they can increase or
decrease in size so that it has got that
flexibility located in the thoracic
cavity as I explained just now before
some time so the lower surface of the
lungs rests on the diaphragm I mentioned
before right the diaphragm denotes the
end of the thoracic cavity so the lower
portion of the two lungs the lower
surface rests on the diaphragm there are
two lungs in the human body the right
lung and the left lung so which is our
right lung this is the right lung and
this is the left lung
now the lung each of these lungs is
again divided into different regions so
the right lung is divided into three
loads loads are nothing but the region's
so the right lung is divided into two
lobes and the left lung is divided into
two lobes the right leg is divided into
three lobes so these are the two loud
lobes in the left clam so this upper
lobe and the lower loop so the upper
lobe is known as superior lobe and the
lower lobe is known as inferior lobe
superior means above so the above the
lobe which is located on the above side
is superior and the one which is on the
lower side is inferior
now similarly the right lung is also
divided into three lobes so this the
above one is the superior lobe and here
this below one is the inferior lobe and
this lobe which lies in the middle of
the superior and
here is known as the middle lobe right
so this is how the lung is divided into
different nodes enclosed by a
two-layered membrane as I said lungs are
the organs where at the actual exchange
of gases take place so these organs
should be located well inside the body
and well protected so to ensure that
protection is surrounded by a
two-layered membrane so here you can see
two black lines right so that is the
double layered membrane and the space
between these two is known as the
pleural cavity so this two layered
membrane is known as pleura pura is the
name of this membrane and pleural cavity
is the space between the two membranes
so this space this white colored space
that is the pleural cavity and this
pleural cavity contains a pleural fluid
to lubricate and prevent friction so
presence of a fluid outside the lungs
will lubricate it will make the surface
slippery and it will prevent reverse
friction because we do not want any kind
of friction friction is nothing but the
resistance to the flow of anything so we
do not want any kind of resistance here
so in order to prevent friction the
pleural cavity is filled with a pleural
fluid lamps play an important role in
breathing and oxygen absorption now
since the lung are the organs which
actually absorbs the oxygen which we
breathe in that is the reason it is
elastic because when we breathe in that
extra air which we are taking inside our
body that needs some extra space as well
so these lungs can expand at that time
and can fill in the air inside then so
it plays a very important role in
breathing and oxygen absorption so we
will look into the next slides but how
exactly the Lance help in oxygen
absorption the next is bronchi what does
bronchi as I said the track here divides
into thinner tubes called bronchioles
enters the thoracic cavity so here you
can see this is the trachea
entering the thoracic cavity so this
cavity is the thoracic cavity it will
divide into bronchi so how will the
bronchi look like let me divide the lung
into the different lobes so this is the
superior lobe this is the inferior lobe
this is the middle lobe and here we have
the superior lobe and the inferior node
now once the trachea enters into the
thoracic cavity what happens it has to
enter into the lungs now right so while
entering into the lungs this entire
thick Dracul tube doesn't enter itself
so it divides into branches and these
branches are known as bronchi so the
right bronchus that means it will divide
into two branches one is right bronchus
and the other one is left bronchus so
the right Broncos will enter inside the
right lung and the left bronchus will
enter inside the left one so this is the
left lung and this is the right term
correct so since in the right lung we
have three different lobes
so therefore the brown there will be
three bronchi reaching into each lobe so
how will the Broncos looks like it will
be something like this one branch
getting into the superior lobe one
branch getting into the inferior lobe
and one branch entering into the middle
lobe
so this is how it will look like
similarly when it enters into the left
lung then what will happen
so one bronchus will go into the
inferior lobe and the other bronchus
willkommen to them superior lobe so that
is why it is say that the right bronchus
divides into three bronchi and the left
bronchus divides into two bronchitis
because there are two loads in the left
lung and there are three lobes and the
right line so what does these bronchi do
they do nothing they just carry the air
which was being carried by trakula
inside the lungs here okay so now the
air is finally reaching the lungs
now the bronchioles and alveoli no
bronchi and bronchioles the names are
quite similar right so what I
bronchioles each bronchus further
divides into finer branches called
bronchioles so here you can see that
this is the track here so this track he
has at entering that inside the lungs it
broke down into the bronchus and each of
these ground kife then further divides
into smaller branches to form
bronchioles so the further branching of
bronchi are donas proach words each
bronchial ends in tiny cluster of air
chambers called alveoli that means first
there was a thick tube or trachea then
tracky avoid entering into the lungs
they divide into bronchi each bronchi
further develops into bronchioles and
each bronchial then further end up in
alveoli so water
al you lie they are a cluster of tiny
air chambers a a chamber means they are
light they look like balloon so alveoli
are balloon like structures which are
filled with air so see this is the
magnified image of an as you like so the
small as you lie which look like
branches in this picture but when you
actually see it's magnified image they
look like this so see they are balloon
like structures and what are these
balloons they are nothing but
chambers so they are air filled balloons
so this air is the one which has been
taken in from the atmosphere through the
nostrils so now these alveoli will
actually transfer this air inside our
body so the actual exchange of gas will
take place at the alveoli level so
alveoli provide a surface where the
exchange of gases can take place so
inside the lungs we have the bronchi
bronchioles and the alveoli so alveoli
are Belling like structures which are
filled with air and the actual exchange
of gases take place along the surface of
the alveoli so the alveoli has alveolar
duct and the walls of these alveoli are
covered with capillaries so walls of
alveoli contain an extensive network of
blood vessels that is capillaries so you
can see here that these are the annual I
the value like structures and these red
color structures which you see they are
nothing but blood vessels what are blood
vessels as the name suggests they are
vessels which carry blood and blood is
flowing throughout our body
right so the alveoli are in direct
contact with the blood so that means if
the Albu I can transfer the air into the
blood the job is done the blood will
then carry this oxygen to different
parts of the body so different part of
the body will receive them yes right so
the actual gaseous exchange takes place
between alveoli and the blood vessels
and water capillaries capillaries are
the smallest blood vessels right so
actual exchange of air take place
between alveoli and the blood vessels
called capillaries so because for this
purpose the walls of the alveoli are
very thin they have very thin walls as
well as the walls
the capillaries are also very thin so
that the exchange of gases can take
place effectively and easily so that is
why alveoli are called
as the functional units of Lance so
whatever we studied in the respiratory
system we saw that the purpose of this
respiratory system is exchange of gases
correct and this exchange of gases did
not take place anywhere either in the
nostrils or nasal cavity or track your
bronchi or drone shots so the actual
exchange of gases took place in the
alveoli so they are the functional units
of lungs all other parts of the
respiratory system they only help in the
passage of air they help the air to
reach the lungs right so I realize is
the place where the actual exchange of
gases will take place and after that the
gas will be transferred to the
capillaries which are the blood vessels
and these blood vessels will then
transport the blood through the to the
rest of the body that means it will
ensure that the air or the gas reaches
each and every cell of the body and then
inside each and every cell the oxidation
of the assimilated molecules will happen
that means the oxidation of food which
we talked about glucose will get
converted into carbon dioxide hydrogen
water and energy so that process will
take place inside each and every cell of
our body right so I hope you got the
entire structure that means how this
respiration is actually happening how
lungs help in absorption of oxygen
because inside the lungs lungs are
actually like bags so inside the lungs
we actually have so many different
things that is bronchi bronchioles and
al your line so what did we see so far
we saw that the air which we breathe in
they entered through the nostrils then
they reach the nasal cavity and then the
pharynx from pharynx it reaches the
track here from trachea it branches out
to form the bronchi the bronchi further
branches out to bronchioles and the bra
bronchioles then ends up in balloon like
tiny water chambers called alveoli the
alveoli are connected or they have the
their walls contain an extensive network
of the blood vessels called capillaries
so these blood vessels will then
transport it to the rest of the body now
this portion that how the blood vessels
actually transported to the rest of the
body that is what we are going to
discuss in the transportation part so
after the respiration is over we are
going to talk about transportation light
so this portion that how actually the
gases are transported to each and every
corner of the body that we will read in
the transportation topic now once it
reaches to each and every corner of the
body that means it reaches each cell of
the body now inside the cell will take
place the cellular respiration that
means oxidation of food will take place
to release energy right now when the
oxidation of food will take place what
will happen carbon dioxide will be
released and this carbon dioxide it will
again follow the same path backwards so
the sense will release that carbon
dioxide into the blood vessels so these
capillaries will again bring it back to
the alveoli from alveoli it will come to
the bronchioles bronchi and then through
the same pathway carbon dioxide will be
given out so now you understand how
oxygen is taken in and how carbon
dioxide is given out clear so now the
question is when we breathe in this
extra air which is coming in where and
how is this extra space created because
for this extra air which is coming in we
need some space right so in this case
air pressure also plays a very important
rule because for the air to move from
one case to another there has to be some
difference in pressure so then you can
move right so let us see that what
happens when we actually thank you
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