- [Instructor] In this chapter we'll be looking at blood.
So, let's start off with the circulatory system.
First things first, you bring in oxygen
and eliminate carbon dioxide.
That's what the respiratory system is used for;
the exchange of gas.
But that gas exchange has to be coupled
with the circulatory system
because your blood is going to move the oxygen.
It's going to move the carbon dioxide through your body.
So it's taking it to every cell in your body
from your head to your toes.
But you also need to make sure the
circulatory system integrates with the urinary system.
Because the urinary system is going
to be getting rid of liquid waste.
Well liquid waste is going to be excess fluid, excess water.
But also extra salts you don't need,
metabolic waste, anything the body has in excess
that can be dissolved in a liquid.
Now we also have the digestive system.
You somehow have to get your nutrients.
So you're eating, you're drinking liquids.
It goes down your GI tract.
So we're talking down in the stomach,
down in the intestines.
Down in the intestines you're going to absorb the nutrients,
absorb the different salts, absorb the water,
it all is put into the circulatory system.
Eventually, what's not absorbed
and what has some extra waste put in there
will be eliminated from the body.
But it just shows that this circulatory system must
integrate with at least these three other systems directly.
Digestive, Respiratory, and Urinary.
So the main three functions of blood
and there's more than these three functions.
These are just the three primary functions.
Probably the first and foremost is transportation.
It allows you to transport your nutrients.
Things like your carbohydrates,
your proteins,
some of the lipids.
It allows you to transport some vitamins, some minerals.
It's also allowing the transport of waste.
Now waste isn't necessarily something that's bad,
it could just be that you have too much of something.
For example, if you have too much salt,
sodium chloride in your blood,
you're going to need to get rid of it.
That is like a waste product.
Hormones.
Well, hormones can be anything from
growth hormone which helps you grow, obviously,
to more complex things like your
Adrenocorticotropic hormone or luteinizing hormone.
So we have various different hormones
from the endocrine system that
are being transported in the blood.
Well the blood also has a regulatory function.
It helps regulate temperature.
Well how does it do that?
Well if you're outside on a 95 degree day,
in the middle of summer with 90% humidity.
What are you doing?
Besides complaining about how hot it is
you're probably going to be sweating.
Sweating is going to be the liquid from in your blood,
is allowing some to seep out of
the skin through capillaries.
Tiny little blood vessels that can help cool you down.
Helps control the water volume in your body.
If you get too much water volume,
it starts to reach the kidneys and excrete it.
pH.
Well it balances your acid and base levels.
The blood is actually buffered within your system.
A buffer is anything that will help
to prevent drastic changes in pH.
Blood helps defense.
Helps prevent against infections.
You have white blood cells in there.
They're going to eat and destroy
anything that's foreign in the body.
It'll also help on a physical nature.
If you have a cut or you're bleeding.
It's going to try and make sure
that you clot that, preventing blood loss.
So, components of blood.
Blood is made of mostly plasma.
Now I have this 55% up here.
55% give or take.
A little more a little less.
It depends on the person.
The idea is the majority though, is plasma.
And the majority of plasma is water.
So most of the liquid portion of
your blood is just pure water.
But you do add in some other things.
Add in some electrolytes.
Electrolytes are salts, sodium,
potassium, chloride, bicarbonate.
You add in some proteins.
Albumins, clotting proteins, globulins.
You add in some hormones, some gases,
oxygen, carbon dioxide.
Some more nutrients and then eventually the wastes.
The plasma is where all of this will be contained.
The rest of the blood is the formed elements.
Now again, don't memorize the percentage here.
Just the idea that it's less than half.
The formed elements are made of three components:
Red Blood Cells, known as RBC's
or more technically Erythrocytes.
You have White Blood Cells, WBC's
or more technically known as Leukocytes.
Then you have Platelets with the
more technical term of Thrombocytes.
Now the reason they're called formed
elements is the red blood cells
and white blood cells are cells,
but the platelets are not cells.
The platelets are just fragments of a cell.
So you can't call all three cells,
that's why they're called formed elements.
Physical structures, they're found within your blood.
So you can actually do a test to see how much
formed elements are in your blood.
Now on the far right, you can see this table top centrifuge.
A centrifuge is just a device that
will spin at very high speeds.
Now when I say very high I mean
10-15 thousand revolutions per minute.
That's moving.
So what's going to happen here is as it spins,
anything that is heavier, anything that has more mass,
more weight, is going to get pushed to the outside edges.
Well in this case, it's pushed to
the bottom of a test tube.
You can kind of think of it as
any of those amusement park rides.
If you've ever been on one of those amusement
park rides that spins and spins.
Where you're up against the wall
and all of a sudden the floor drops out,
but yet you don't fall down to the floor.
You have this force, this centrifugal force
pushing you out against the walls.
It's the same idea here.
The red blood cells are going to
have the most mass, the most weight.
They're pushed the furthest down into the test tube.
Then you get the platelets and white blood cells
kind of mixed in this little tiny layer,
there's not many of them.
All the plasma's up top.
It's liquid.
So it's the least dense.
It has the least mass.