L25 : Questions - Biology Control & Co-ordination, Science Class 10 Video Lecture

hello friends this video on control and
ordination part 25 is brought to you by
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with this we have reached towards the
end of this lesson so now we will have a
look at few questions based on whatever
we have studied so far in this lesson so
let us look at the first question it
says which of the following is a plant
hormone insulin thyroxine is frozen or
cytokine a very simple so cytokine in is
the right answer
what is insulin by the way insulin is a
hormone which is secreted by the
endocrine part of the pancreas what does
it do it decreases the level of glucose
in blood here what is pyroxene it is
recruited by thyroid gland it helps the
metabolism of body is trojan it is a
female hormone it is secreted by the
ovaries and it helps in the development
of primary and secondary sexual
character in females and cytokine hence
it is a naturally occurring plant
hormone which promotes plant growth next
one the gap between two neurons is
called
a then right synapse acts on impulse
right it is salams so synapse is the gap
between two neurons so if this is the
axon of one neuron and if this is the
dendrite of another neuron so the gap
between this two is the synapse so for
an information to reach from one neuron
to another they have to cross the
synapse so here we can see this small
circular molecules they are nothing but
neurotransmitters and these objects here
they are nothing but the receiving
molecules so they are to see
the information in the form of these
neurotransmitters the brain is
responsible for thinking regulating the
heartbeat balancing the body all of the
above of course it is all of the above
now can you tell me which part of the
brain is responsible for thinking it is
cerebrum right
which part regulates the heartbeat
heartbeat is something which is
involuntary right it is not under our
control
so any movement any movement related
things comes under the high in the brain
so heartbeat is again movement related
but it is involuntary
so anything involuntary is controlled by
the medulla oblongata balancing the body
balancing the body maintaining postures
all those things are controlled by
cerebellum because they fall under the
voluntary movements tactical and
thinking by cerebrum what is the
function of receptors in our body think
of situations where receptors do not
work properly what problems are likely
to arise so what are receptors we have
spoken about receptor said the word
receptors itself means receiving
something so receptors are nothing but
our sense organs so they have
specialized cells which can actually
sense things happen outside or they can
sense the external stimuli so the
function of receptor is detect external
stimuli and send them to central nervous
system in the form of electrical impulse
so that is the function of receptors
like and in case of reflex action
instead of sending it to the brain they
send it to them spinal cord so that is
why it is written they send it to the
central nervous system
now think of situations where the
receptors do not work properly
what would happen now receptors are
present in our sense organs so if I
I if our eyes do not work properly we
will not be able to view things
correctly so even faced a lot of problem
right if I would you stop working
property we will not be able to hear
sounds that will again cause a problem
right so let us look at some situations
like that it is suppose if if we step
into the fire what tells us that we are
feeling hot or we are feeling the pain
it is because of the skin so the skin
has receptors so skin is the sensory
organ now if the skin receptors stop
working we do not feel the pain at all
we do not feel the heat at all so what
will happen we will not remove I like
because I'm telling Magnus we receive
that information no information will go
to our brain and our brain will not take
any decision or our spinal cord will not
take any decision so we would not remove
our leg and what will happen our legs
will get burnt similarly let us suppose
this boy is standing and he sees a big
tiger coming in front of him but if his
eyes are not working properly he will
not be able to see the tiger so he will
not be running yield is simply standing
so it is very very important that the
receptors work properly because the
receptors are the one who actually
brings the external information inside
the body and sends them to the nervous
system to take a decision all right okay
let us look at the next question
how does phototropism occur in plants
just now we spoke about phototropism it
is nothing but the movement of plants in
response to light so it is a bending of
plant in response to light shoots are
said to be positively phototropic why
because they grow towards the direction
of light whereas roots are negatively
phototropic because they will grow away
from the direction of light now what
causes this kind of bending why does
this phenomenon happen that's because in
presence of unidirectional light there
is a naturally occurring plant hormone
called auxins which are produced at the
shoot tips
now these options will get diffused
towards the shady side so the
concentration of
auxins increase towards the shady side
therefore the shady side will grow more
and therefore there is our overall
bending of shoot towards light like this
so I think I do not need to explain it
again because just before sometime I'd
explain it so I am just reviewing it
once again so that you know how to
answer your questions or you can at
least jot down the points together let's
look at another question how does
control how does chemical coordination
occur in plants as I said it happens
with the help of the plant hormones
right
so chemical coordination of person
plants with the plant hormones these
hormones are produced at a site and then
diffuse to the required area that means
they move from the diffuse from the area
of production to the area of action like
in human beings also the hormones are
produced at one point and then they are
carried by the blood to the target
organs so similar gene plants also the
same thing happens they are produced at
one place and then they diffuse to
another area where it is needed so
examples of some of the plant hormones
are absence gibbelins and cytokinins
which help in growth of plants and
abscisic acid which stops the growth of
plants what is the need for a system of
control and coordination in an organism
now after going through this entire
lesson I think I do not need to answer
this you know this for yourself right
what is the significance of control and
coordination so you would have
understood by now that whatever we do
whatever our hands - whatever our legs
do everything is being decided by the
nervous system sometimes we feel angry
sometimes we feel sad these feelings
also come from the hormones right so
needless to say there is a lot of
importance of the control and
coordination now we know that in
multicellular organisms like us the body
is made up of several cells and each
cell has been assigned a specific
function right now it is very important
that
the function of each of the cells are
well coordinated and well synchronized
with the other cells so that together
all the cells can perform the correct
functions of the body so each cell in an
organism's body is assigned a specific
function control and coordination is
required to coordinate these functions
of the several cells in the body right
let us take some example when you answer
your question paper what happens your
eyes read the questions your eye sees
the question actually then the
information is sent to your brain so the
cells which make up the eye the cells
are doing their own job and their job is
to see
similarly the cells which form the brain
their job is to think so once the
information reaches the brain only then
the brain cells will start thinking
right so that carrying that information
from the eye cells to the brain cells is
me necessary right so for that we have
control and coordination now once that
information reaches brain than the brain
cells will start their job now the brain
cells will think of the answer and then
again they will send that answer back to
the muscle cells of your hand so that
your hand can move to write the answer
then so again for that a communication
is needed so there has to be correct
communication between the different
parts of the body because each cell is
doing their own job but their jobs must
be done in a coordinated way amongst
each other and for that we need the
system of control and coordination so if
there is no coordination then life will
be half as it let us suppose that there
is no coordination your brain cells will
not know when to think your hand will
not know where to write right so
everything happens because of that
coordination how are involuntary actions
and reflex actions different from each
other so when we say involuntary the
word involuntary itself means that
something which does not happen at our
will that means something will which
happen on its own
so the muscle movements
don't need thinking by brain so it
happens on its own there is no thinking
of brain involved whereas reflex actions
are the instantaneous action in response
to the stimulus that means in reflex
action brain does not play in your own
the entire role is played by the spinal
cord and in involuntary actions there is
no thinking by then thinking means
thinking part is done by the cerebrum of
the brain so cerebrum has no role in
voluntary movements are controlled by
the hind brain that is by medulla
oblongata so made Yoona of the water
will control the involuntary actions and
spinal cord will control the reflex
action example of involuntary actions
will be hard to beat reflex action is
when you remove your hand on touching a
hot object so we have already I have
already shown you the flow of reflex
action so how that entire flow happens
that comes from the sensory organs to
the sensory nerve then it enters the
spinal cord through the dorsal dorsal
cord then it this goes to the gray
matter of the spinal cord where the
processing happens then the output goes
to the through the ventral horn to the
motor nerve and then the motor nerve
cadell's it to the muscle cells compare
and contrast nervous and hormonal
mechanisms for control and coordination
in animals now when I talk of the
nervous mechanism it consists of the
nervous system and the horn Moodle
mechanism is the endocrine system so
nervous system consists of brain spinal
cord and the peripheral nerves endocrine
system consists of the hormones secreted
by the endocrine glands into blood right
that is very simple
next is a nervous system information
transfer happens in the form of
electrical impulses right so yet
electrical impulses travel throughout
the body but in this case information
transfer happen in the form of chemical
messengers so what are those chemical
messengers they are nothing but hormones
so here the hormones are secreted by the
endocrine glands into the blood blood
then carries the hormones and then the
hormones hit the target cells in nervous
system the information transfer is fast
whereas in hormonal mechanism the
information transfer is slow okay here
it is very fast like because the
electric impulse I have the capability
to travel really fast but in case of
hormonal mechanism it happens by
diffusion so it takes a lot of fat so
the response time is less so when the
information will travel so fast so the
response time will be very less like the
moment you get a stimuli you responds
very quickly but in case of hormonal
mechanism the wherever there is a
stimuli the response is there and that
response is very gradual so the response
time is more for example growth we do
not grow overnight right so it takes
time to grow it takes time for our
fingers to increase in length for our
high to increase in length right but in
case of nervous mechanism the heart
keeps beating so it happens quickly
it doesn't take lot of time right
similarly if we feel like walking
so our legs start moving immediately or
our hands start moving immediately so
the response time is very less okay so
with this I think we came towards the
end of this lesson
and I hope that this video on control
and coordination would have helped you
in understanding the mechanism of the
nervous system and the endocrine system
in human beings and also the nervous
system in other animals and coordination
in plants so please keep watching see
you all in the next lesson thank you
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