Valves of the Heart: Atrioventricular and Semilunar Valves (Nursing)

00:01 So speaking of heart's valves, a heart valve ensures unidirectional blood flow through the heart.

00:09 These are going to open and close in response to pressure changes.

00:14 There are two major valves found in the heart.

00:18 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.

00:30 The other type of valve that we have in the heart is the semilunar valves.

00:35 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.

00:48 So let's take a closer look at these valves.

00:52 First we have the tricuspid valve.

00:55 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.

01:09 The bicuspid valve is also an atrioventricular valve found on the left side of the heart between the left atrium and the left ventricle.

01:21 The next valve is going to be the pulmonary valve.

01:25 The pulmonary valve is a semilunar valve on the right side of the heart that separates the right ventricle from the pulmonary trunk.

01:37 We also have the aortic valve.

01:40 The aortic valve is also a semilunar valve and this is going to separate the left ventricle from the aorta.

01:51 So our two atrioventricular valves are going to prevent backflow into our atria when our ventricles contract.

02:01 The tricuspid valve on the right side of the heart is made up of three cusps that lie between the right atria and ventricles.

02:11 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.

02:21 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.

02:50 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.

03:10 So how did these AV valves function? Blood returning to the heart is going to fill the atria.

03:19 As the blood is filling the atria, it is pressing up against this AV valve.

03:25 This increases the pressure and eventually will force that AV valve open.

03:32 Once the AV valve is open, the ventricle is now going to start to be filled.

03:37 As the ventricle fills, the AV valve flap is going to hang limply into that ventricle.

03:45 Once the atria contracts, this is going to force any additional blood that is still in the atria into the ventricle.

03:56 The semilunar valves are going to have a little bit more activity.

04:01 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 trunk.

04:19 And on the other side, on our aorta side, the aortic semilunar valve is gonna be located between the left ventricle and the aorta.

04:31 Both of these valves are going to open and close in response to pressure changes in the heart.

04:38 The semilunar valves consist of three cusp that roughly resemble a half-moon which is where they get their name.

04:49 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.

05:03 This forces those valves open.

05:08 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.