1. Cardiovascular System
Review of The Heart

2. Cardiovascular System
For the purpose of this course, interest in cardiovascular system are limited to :
Blood circulation system
Cardiac cycle
Cardiac output
Cardiac work
We’ll try to relate the cardiac function of the heart with the operation of heart assist device particularly VAD.

3. Cardiovascular System
Anatomy of The Heart

4. Cardiovascular System
Heart is a muscular organ in human body where the main function is to pumps blood to all over the body.
Located in the chest between the lungs behind the sternum and above the diaphragm.
Heart walls composed of three layer of muscles : epicardium, myocardium and endocardium.
Myocardium is the thickest muscle among them. It is the one that contracts and thus responsible for pumping action of the heart.
The heart also has four chambers consists of two atria and two ventricles.
Blood flow into atria and then fill the ventricles. Then blood will be pumped out from the heart when ventricles wall contracts.
Atria acts like a reservoir which receives blood that returns to the heart while ventricles acts as a pump which ejects blood out to the body.

5. Cardiovascular System
Layers of Heart Muscle

6. Cardiovascular System
Valves
There are four valves in the heart which will ensure only one-way flow of blood through heart chambers.
All these valves can be categorized into two types i.e. atrioventricular valves and semilunar valves.
Atrioventricular (AV) valves located between atrial and ventricular chambers. It prevents backflow to atria when ventricles contract.
AV consists of mitral valve (also known as biscupid valve) at left side of the heart and tricuspid valve on the other side
Semilunar valves consists of pulmonary valve and aortic valve.
These valves guards the bases of the two large arteries leaving the ventricular chambers.

7. Cardiovascular System
Blood Circulatory System

8. Cardiovascular System
Human blood circulatory system can be divided into two parts i.e. pulmonary circulation and systemic circulation.
Oxygenated blood is oxygen rich, CO2 poor blood indicated by red color.
Deoxygenated blood CO2 rich, oxygen poor blood indicated by blue color.
Pulmonary Circulation
Circulation of blood from heart to lungs and back to heart.
Deoxygenated blood flow out of heart through pulmonary artery to the lungs.
At lungs, oxygen is picked up and CO2 unloaded.
Oxygenated blood then goes back to heart via pulmonary vein.
Systemic Circulation
Blood circulates from heart to all other parts of body except lung.
Oxygenated blood leaves heart through aorta to the body.
Oxygen in blood diffuses into cells and CO2 diffuses from cells into blood.
Deoxygenated blood then goes back to the heart through vena cava.

9. Cardiovascular System
Physiology of The Heart
Blood Flow in The Heart
Deoxygenated blood from the body returns to the heart via vena cava and enters the right atrium.
Then, the blood will fill the left ventricle before the ventricles contract ejecting the blood to the lungs through pulmonary artery.
Oxygenated blood from the lungs goes into the heart via pulmonary vein and enters the left atrium.
The blood then passes into left ventricle and ejected into the aorta.
Mechanism of Pumping
Blood returning to heart will enter the atria
The blood put pressure against the AV valves which forces the valves to open.
Blood will fills the ventricles. Contraction of atria will force additional blood into ventricles.
Then, when ventricles contracts, blood will forces the AV valve to close.

10. Cardiovascular System
At the same time, blood will put pressure against semilunar valves forcing them to open.
As ventricles relax, blood flows back from arteries, filling the leaflets of semilunar valves and forcing them to close.
Notes:
‘Blood Flow in The Heart’ describes the path which blood go through in the heart.
‘Mechanism of Pumping’ describes what happens in the heart during one cardiac cycle.