Blood Flow through the Heart (Nursing)

00:01 So now let's look at the pathway of blood from the right side of a heart.

00:07 So on the right side of the heart, we have three major veins that are going to come into and meet with the right atrium.

00:15 These are the superior vena cava, the inferior vena cava and the coronary sinus.

00:23 The superior vena cava is going to be returning blood from above the diaphragm.

00:29 The inferior vena cava is going to be returning blood from below the diaphragm and the coronary sinus is going to be returning blood from our coronary veins and coronary circulation.

00:43 From these veins, we go to the next chamber which is the right atrium.

00:49 From the right atrium we go through the first atrioventricular valve, this is the tricuspid valve.

00:59 From the tricuspid valve, blood is now going to flow into the right ventricle.

01:07 Once in the right ventricle, it is now going to be pumped out of that ventricle into pulmonary circulation by way of the pulmonary semilunar valve.

01:21 Once it travels through this valve it goes through the pulmonary trunk to the pulmonary arteries and eventually this blood is going to go to the lungs where it will be oxygenated at the alveoli.

01:40 On the opposite side of the heart or the left side of the heart, we have four pulmonary veins that are going to feed into the left atrium of the heart.

01:52 Once in the left atrium, the blood will travel through the mitral valve into the left ventricle of the heart.

02:01 When the left ventricle of the heart contracts, the blood will be pumped out by way of the aortic semilunar valve into the aorta where then it will go through systemic circulation delivering oxygenated blood to our body's tissues so that our body may be able to use that oxygen to undergo certain metabolic functions.

02:26 There are equal volumes of blood that are going to be pumped through both circuits.

02:31 So we're gonna have an equal volume of blood pumped to that lungs as well as to the rest of the body.

02:38 There are differences though and that the pulmonary circuit is a shorter circuit and it is a low pressure circulation.

02:48 The systemic circuit however is much longer as it has to start at the heart and pump throughout the whole entire body.

02:57 It is also a high friction circulation as it's going to encounter a lot more resistance than our pulmonary circuit which is shorter.

03:08 Because of this, the anatomy of the ventricles is going to reflect this difference.

03:15 The left ventricle is responsible for getting blood throughout the whole body and therefore the walls of this ventricle are three times thicker than the walls of the right ventricle.

03:28 This allows for the left vebtrivle to pump blood with greater pressure or higher pressure as compared to pulmonary which does not need a lot of pressure to get the blood to the lungs.

03:44 You can see the differences between the left ventricle and the right ventricle in this image.

03:50 Notice that the left ventricle is much thicker than that of the right ventricle.

03:56 Again, this is because the left ventricle has the job of pumping blood through a very high pressure system that needs to get blood from the heart to all parts of the body.

04:10 Whereas the right ventricle only needs to get blood through the low pressure pulmonary circuit which is right next to the heart in the lungs.