So speaking of heart's valves, a heart valve
ensures unidirectional blood flow through the heart.
These are going to open and close
in response to pressure changes.
There are two major valves found in the heart.
We have the atrioventricular valves which are gonna be
located between the atria which are our receiving chambers
and the ventricles which are our pumping chambers.
The other type of valve that we have
in the heart is the semilunar valves.
These are going to be located between the
ventricles which are going to be pumping blood out
and the major arteries including
the aorta and the pulmonary trunk.
So let's take a closer look at these valves.
First we have the tricuspid valve.
The tricuspid valve is an atrioventricular valve that is
going to be between the right atrium and the right ventricle
Next, we have our bicuspid valve the bicuspid valve.
The bicuspid valve is also an atrioventricular
valve found on the left side of the heart
between the left atrium and the left ventricle.
The next valve is going to be the pulmonary valve.
The pulmonary valve is a semilunar
valve on the right side of the heart
that separates the right
ventricle from the pulmonary trunk.
We also have the aortic valve.
The aortic valve is also a semilunar valve and this is
going to separate the left ventricle from the aorta.
So our two atrioventricular valves are going to prevent
backflow into our atria when our ventricles contract.
The tricuspid valve on the right side of the heart is made up
of three cusps that lie between the right atria and ventricles.
The mitral valve or the left atrioventricular
valve is going to be made up of two cusps
and lies between the
left atria and ventricles.
On these valves, we have these
structures known as chordae tendineae
and these are going to anchor the cusp
of these AV valves to papillary muscles
These muscles hold the valve flaps in a closed
position and prevent the flaps from everting
back into the atria especially when we have this
increased pressure in our heart during pumping.
Here, we have an image of the chordae tendineae
which are the chords that are connected to the valve,
the papillary muscles that
are controlling these chords
and as well the internal ridges inside of
the atria known as the trabeculae carneae.
So how did these AV valves function?
Blood returning to the heart is going to fill the atria.
As the blood is filling the atria, it is
pressing up against this AV valve.
This increases the pressure and
eventually will force that AV valve open.
Once the AV valve is open, the
ventricle is now going to start to be filled.
As the ventricle fills, the AV valve flap
is going to hang limply into that ventricle.
Once the atria contracts, this is going to force any
additional blood that is still in the atria into the ventricle.
The semilunar valves are going
to have a little bit more activity.
These are gonna be responsible for preventing
backflow from our major arteries back into the heart
On the pulmonary side, the pulmonary
semilunar valve is going to be located
between our right ventricle and the pulmonary
And on the other side, on our aorta side,
the aortic semilunar valve is gonna be located
between the left ventricle and the aorta.
Both of these valves are going to open and close
in response to pressure changes in the heart.
The semilunar valves consist of three
cusp that roughly resemble a half-moon
which is where they get their name.
So how did the semilunar valves function?
So as the ventricles contract and
the intraventricular pressure rises,
blood is going to be pushed
up against the semilunar valves.
This forces those valves open.
Subsequently, as the ventricles relax and
the intraventricular pressure goes back down,
blood is going to flow back from the arteries
such as the pulmonary trunk or the aorta
and instead of flowing back into the heart, they're
going to fill the cusp of the semilunar valves,
forcing them to close.