Where is the aortic semilunar valve located
Heart Valves - Atrioventricular Valves - Semilunar Valves - Tricuspid - Bicuspid
welcome to 5-minute school today's video
will be talking about the valves of the
heart I've included a diagram here which
shows the heart in a good amount of
detail and there are quite a few labels
on here as well but in today's video
we'll just be talking about the valves
which you can see on the left and right
side of the hearts on the left side here
on the right side here and we also
consider semilunar valves here now we
know already that the heart consists of
cardiac muscle and if you didn't know
cardiac muscle is basically consisting
of myocardial cells and between these
myocardial cells they are joined
together by intercalated disks but it's
not just cardiac muscle which makes up
the heart we have a fibrous skeleton in
place which helps to keep the structure
of the heart
now this fibrous skeleton is going to be
consisting of connective tissue so just
to make things a bit more clear the
atria and the ventricles they are
separated into two functional units by a
fibrous skeleton which is made up of
connective tissue and obviously we need
to enable blood to pass through this
fibrous skeleton so there are valves or
atrioventricular valves embedded within
this fibrous skeleton and this allows
the passage of blood to go through okay
so the atrial ventricular valve between
the right atrium remember this side is
the right side the right atrium and
ventricle is known as the tricuspid
valve and this has three flaps you can't
see it so well in this image but when
the valve is actually sure it is quite
clear that there are three components to
the valve on the left side between the
left atrium and ventricle we have the
bicuspid valve which is also known as
the mitral valve and this consists of
two flaps so the atrioventricular valves
allows blood to flow from the atria to
the ventricles but normally prevents the
backflow of blood and opening and
closing of the valves occurs due to
pressure differences between the atria
and ventricles remember when the atria
is filling with blood these valves are
closed if they were opened
then blood would just fill the atrium
straight away fall into the ventricles
so when the atria is filling with blood
these valves are closed when the
pressure in the atria gets very high
then it forces these valves to open and
then blood passes through from the atria
into the ventricles and then when the
pressure is building up in the
ventricles this pressure causes these
valves this snapshot okay and that's how
blood can pass on the next cycle from
the atria because the valves were
already shot from the previous closure
from the ventricles okay so what we need
to bear in mind is extremely high
pressures which are produced by the
ventricles could invert the atrial
ventricular flaps now what we need to
remember is we're just discussing the
basic physiology of the heart
there are various cases where we have
pathological processes going on and for
example if we have excessive pressure in
the ventricles because the heart is
trying to compensate for lack of oxygen
in different parts of the body so the
ventricle is pumping extremely high
pressures of blood then this pressure
could be so high that it could force
these flaps to push back open sorry to
invert into the atrium okay so this is a
pathological disease so high extremely
high pressures produced by the
ventricles could invert the
atrioventricular flaps and this is
prevented in some cases by a contraction
of papillary muscles within the
ventricles which are connected to the
atrial ventricular flaps by strong
tendinous cords called corded chordae
tendineae
okay you can see them from this image
here they're connected to the papillary
muscles of the heart and it's a fibrous
cord which is attached unto the valves
and it's see clearly this core called
here which is attached onto the valves
to prevent them from inverting and
that's sort of a a prevention but
remember in some cases
that could be damage to these cords as
well so we're just learning the
physiology for now but is important to
bear that in mind
lastly we're going to talk about the
semilunar valves and they are located at
the origin of the pulmonary artery in
aorta they open during ventricular
contraction and when the pressure in the
arteries is greater than the ventricles
they snap show okay so let's have a look
at them here you can see on from the
right side of the heart the ventricles
are here here we have the pulmonary
artery and we have the semilunar valve
here which obviously prevents backflow
of blood from the pulmonary artery back
into the ventricle so it's a similar
it's the exact same purpose as the
atrioventricular valve so the pressure
in the ventricles is going to get very
high in force these valves open and then
blood is going to go into the pulmonary
arteries but when the pressure here is
higher than the pressure in the
ventricles these valves are going to
snap shut okay so that's everything I'm
going to talk about in this video thank
you very much for watching
