Hello, today we are going to talk about the
regulation of body temperature.
So let’s start right in to what is body temperature?
Body temperature is really quite simple.
It is the heat production minus the heat loss.
So there are five main ways to have heat production.
But the most important, that it
comes is the most kilocalories burnt per day is
in basal metabolic rate or basal metabolism.
So this involves to simply not doing anything,
just being alive you’re burning kilocalories,
and this is an important process of your metabolism.
This can a course change with
there is a different condition, such as,
if you have a high thyroid metabolism
or a thyroid hormones, you have an increasing metabolism.
If you have a low amount of thyroid hormones,
you have a decreasing metabolism.
The Thermic Effect of Food is another way you increase
heat production. As you intake food,
you need to digest and absorb those food macromolecules.
You need to repackage them
into different portion, so you can use fats, and
carbohydrates, and proteins, and all that takes
energy. And that energy part that is heat liberation.
Finally, anytime you move whether it be you are simple
wiggling in your seat, you are walking to
and throw with activities of daily living. Or if you
are actively exercise it all produce heat.
So base on the metabolism, thermic effect of food,
and exercise are all normal ways
you increase heat production.
The final two ways of increasing heat production
are usually associated with a cold stress.
If you are involved in an area, which is very cold,
sometimes you can shiver.
Shivering is muscle contraction without involving
any useful work and that produces heat.
The final way is through brown adipose tissue.
Brown adipose tissue is a very specialize form
of adipose tissue. And what happens here is, there is
an increase in the heat production
because your mitochondria will produce heat. And in
this specific adipose tissue is there are
high concentration of mitochondria, and have a specific
protein in them that uncouples oxidized phosphorylation.
Therefore, as you increase the amount of energy
production more heat is liberated.
Now, brown adipose tissue is most important in the
infant less important in the adult.
Now, there are four primary wares of heat loss, and it involves
radiation, conduction, convection and evaporation.
Radiation is the first one we talk about, and then
involves simply a movement of heat
between two bodies or two objects. And this
base upon the temperature, which each of
those objects are. And there’ll be electromagnetically
waves between those two objects,
a hot object to a cold object. So usually, your body
is warmer, then let’s say, a wall that’s too next to,
and so, you are radiate heat out towards that colder object.
Conduction is less important in terms of heat loss,
because they’re need to be direct physical contact
between two substances or items that are different
temperatures. So you need to be right
in close proximity to that object. And so, if
you are standing up, you only parts that you have
good conduction with is at your feet.
Now, if you are sitting down on a chair, that’s a
little bit different. Now, you have a little bit of
conduction between your back and your upper legs.
But again, the amount of availability of losing heat
via conduction is usually limited.
Convection is more widely used as heat loss mechanism,
but this needs to have some sort of medium.
And that medium can either be air or water.
And why this is important, is that air rushes
across the skin, you heat up the air right above
the skin layer. But then, the wind or movement
blows past it. And therefore, you have to heat up
another layer of air. And so, the more that’s
wiped across or a more as blown across the skin
the more you have to heat up.
Finally, Evaporation only occurs as a heat loss
mechanism. And for this particular one, this is
involved the amount of sweating that a person undergoes
can then be used as vapotory sweat.