Organisms which Regulate Video Lecture - NEET

hi it's mr. Andersen and welcome to the
thermoregulation podcast basically I'm
going to talk about how organisms
regulate their internal temperature or
not so basically this right here is a
thermal image of the human arm you can
kind of see that right here and it's
holding on to a snake and so this shows
us the temperature over here so again
our internal body temperature is going
to be around 37 degrees Celsius what's
the temperature of the snake well
temperature the snake is around room
temperature and that's because they're
an ectotherm
and so before we get to that let's talk
about heat if we have a candle right
here and then you've got your hand right
here there are basically ways that you
can transfer heat from your candle to
your hand and so one way you could do
that would be to stick your finger right
in the flame and when you do that the
molecules of the flame are going to
interact with the molecules of your
finger and that's conduction so it's
actually going to heat you up that way
there's other ways that we could
transfer heat though if you sit right
here and you're not touching the actual
flame you're still going to feel a
little bit of heat but if you put your
finger way above the flame like this
it's going to be way more painful up
here than it is on the side and the
reason why is a second way that you can
transfer heat and that is through
convection
now what's convection that's movement of
fluids what's the fluid that's actually
heating up your finger it's the air it's
getting really hot hot air rises and so
it's going to heat you up way up here at
the top so that's two ways we can
transfer heat next way we could transfer
heat is if you're to put your finger
over here and then we were have a vacuum
in here you still would get a little bit
of heat it wouldn't be a lot but you get
a little bit of heat from the candle
over here and that's through radiation
radiation is important because if this
is the Sun and this is you on the earth
that light is moving through the vacuum
that is space and it's eventually
getting to you and so these are all ways
that we can get warm we can get warm by
the radiation of the Sun or the movement
of air or even touching like a warm Rock
something like that but there's another
way that we can actually generate heat
since we're living things and that is
through respiration so through
metabolism we can generate
a little bit of heat and so life has
evolved to different strategies in order
to interact with heat and the first
strategy is called ectotherm and that
basically means heat from outside these
things right here are ectotherms and so
these are Turtles what does that mean
they derive their temperature from their
surroundings so they're going to be the
same temperature as room temperature and
so what's the advantage of that the
advantage of that is that they don't
have to burn up any energy creating heat
inside themselves and so you don't have
to feed a turtle that often if you're a
big snake you might eat once a month or
once a year you eat something big enough
because they don't require a huge amount
of energy now what's the disadvantage of
that if it's really really cold
then all of them metabolism all the
enzymes inside your body are going to go
slowly as well and so lots of times
they'll warm themselves up in the
morning by climbing up on a rock or
basking in front of the Sun if you're an
endotherm like this ground squirrel
right here you don't have to worry about
that you're good to go but and the
reason why is that you're generating
heat inside you you have metabolism
going so what is the temperature of this
ground squirrel it's probably close to
ours and if it's cold out it's probably
close to ours and if it's really warm
out it stays close to ours as well and
so the advantage of being an endotherm
is that your internal temperature is
always going to be exactly the same
what's the disadvantage of that you have
to constantly eat over and over and over
and over again okay so how do we
maintain this since we're endotherms
well basically we use a negative
feedback loop and so the way you sense
it is using something called your
hypothalamus and so basically on the
underside of your brain you have a
hypothalamus it constantly is figuring
out what our body temperature is and so
if I temperature were to go too high it
goes above a set point basically we're
going to react to that we're going to
react to that in a number of ways one
way we can react to that again if we get
too hot is that we're going to start to
sweat another way that we're going to do
that is we're going to start to
vasodilate
we're going to dilate the capillaries so
we're going to move more blood near the
surface of our body so we can lose that
as heat that's going to bring our
temperature down again let's say it goes
to low what do we do well if it goes to
low then we're going to start to get
goosebumps
hold that skin into in close to
ourselves we're also going to start to
vasoconstrict we're going to hold that
body clip that temperature close to our
body and so basically that's going to
raise our temperature back to that set
point and we're constantly doing that
and the advantage of that is to keep our
body temperature close to the set point
and that's a perfect set point for all
the enzymes inside our body to work and
so that's the thermo regulation and I
hope that's helpful