hi let's talk about the valves of the heart so the heart has two sets of valves there are the
atrioventricular valves that are going to send blood from the atria into the ventricles hence
their name and then there are the semilunar valves which send blood from the ventricles
out into a respectively named vessel so for instance there is a semilunar pulmonary valve
which we can see anterior there and a semilunar aortic valve which we can see posterior
there so the atrioventricular valves let's start with those on the right side of the
heart we have the tricuspid valve the tricuspid valve gets its name because there are three
cusps there is an anterior cusp a posterior cusp and a septal cusp most of the action of this valve
occurs with the anterior and the posterior cusps and there's very little if any movement from
the septal cusp now the bicuspid or mitral valve separates the left atrium from the left ventricle
and we can see that there is an anterior cusp and a posterior cusp looking within the ventricles we
can see how the cusps are anchored to papillary muscles via the cordy tendineae so for however
many cusps there are in the valve there will be that many papillary muscles and they're
named for the various cusps but there isn't fidelity between the cordy tendonity that come
from a particular cusp to a particular papillary muscle so for instance as we can see here there
are cordy tendineae from the anterior cusp going to this anterior papillary muscle and there are
also chordae tendineae from the posterior cusp also going to that anterior papillary muscle
these av valves are going to be open during diastole so that blood may flow freely through
the atria and into the ventricles they'll remain open through atrial systole and they'll close
in response to the increase of intraventricular pressure during ventricular systole
and these papillary muscles and the cordy tendony prevent the cusps of the valves from
flowing backwards into the atria so or prolapsing back into the atria
now the semilunar valves work in a whole different way the semilunar valves
are wide open during ventricular systole because that blood needs to leave the ventricles and go
out to the lungs and the systemic loop but it also needs to close during diastole and what happens is
during diastole as interventricular pressure is dropping blood begins to flow back toward
the ventricles but it catches these cusps and it brings them into very close approximation
so that it actually closes the valves now we can see the base of the heart here has been incised
here is the right article we can see the left oracle is there
the semilunar pulmonary valve is anterior and the aortic valve is posterior if you're ever
hurting to distinguish one from the other you can quickly look to see that the
aortic valve should be in association with the ascending aorta which has
the left coronary artery and the right coronary artery in association with it now these
semilunar valves have three cusps each the pulmonary valve is going to have an anterior cusp
and then left and right cusps the aortic valve will have left and right cusps and a
posterior cusp and so what we can see is that the right cusps of the valve align and the left cusps
of the valves align and then there's an anterior and a posterior cusp
so these are the semilunar valves and they work very distinctly differently than
the atrioventricular valves thank you very much for your time