1. The Heart
How it works

2. The Heart

3. Facts
The heart is the organ that supplies blood and oxygen to all parts of the body and gets rid of waste as well
It is about the size of your clenched fist
It weighs 10.5 oz
The heart is surrounded by a fluid filled sac that helps to anchor the organ in place and provides lubrication and protection called the pericardium.

4. Superior Vena Cava Large diameter Short vein
Carries deoxygenated blood from the upper half of the body to the right atrium

5. Inferior vena Cave Large vein
Carries de-oxygenated blood from the lower half of the body to the right atrium

6. Right Atrium One of four chambers in the human heart
It receives de-oxygenated blood from the SVC and the IVC
Pumps the blood into the right ventricle

7. Atrioventricular Valve - Tricuspid
On the right side between the right atrium and the right ventricle
Three leaflets that open when the atrium contracts to push the blood into the ventricle
Prevents the backflow of blood

8. Right Ventricle The second of four chambers for the blood to enter
Receives the deoxygenated blood and pumps it into the pulmonary artery through the pulmonary trunk
More muscular than the atrium

9. Pumping
The right ventricle will contract when there is the proper amount of blood and pressure in the chamber
The atrioventricular valve (tricuspid) will close so the blood DOES NOT go back into the right atrium
The pulmonary valve will open when the pressure from the contraction is increased.

10. Pulmonary Valve Also called the semilunar valve
Lies between the ventricle and the pulmonary trunk then arteries
It disperses the deoxygenated blood into the pulmonary arteries and prevents backflow

11. Pulmonary Arteries Arteries carry blood away from the heart!
Usually it is oxygenated
BUT These arteries have deoxygenated blood and it is transferred to the lungs

12. Pulmonary Veins Large blood vessel
Always carry blood to the heart, usually deoxygenated
BUT these carry oxygenated blood from the lungs back to the heart
There are four pulmonary veins

13. Left Atrium Gathers the oxygenated blood from the pulmonary veins
When the right atrium contracts, so does the left

14. Mitral Valve AKA: Atrioventricular valve
On the left side of the heart
Separates the blood in the atrium from the blood in the ventricle
Has two leaflets
The diagram shows a malfunction where it allows blood back into the atrium – Prolapse
Prevents the backflow of blood

15. Left Ventricle Very muscular 4th chamber of the heart
Must pump the oxygenated blood to all parts of the body through the aorta

17. Pumping
The oxygenated blood is pumped from the lungs where the oxygen is ‘picked up’ to the heart by the pulmonary veins.
It then enters the left atrium and when there is sufficient volume and pressure (greater than that in the left ventricle) the atrium contracts which opens the mitral (atrioventricular) valve. The blood rushes into the ventricle and when the pressure and volume here are correct the muscular ventricle will contract and the mitral valve closes and the aortic valve opens.
There is NO backflow of the blood in the heart
The musculature of the left ventricle is greater than that of the right. WHY?

18. Aortic Valve
Valve that is opened when the left ventricle contracts allowing the oxygenated blood to enter the aorta
Normally has three leaflets
The blood in the ventricle must have a greater pressure than that in the aorta

19. Aorta The largest artery in the human body
Originates from the left ventricle and extends down into the abdomen
It distributes oxygenated blood to all parts of the body
The blood from the aorta first passes into the coronary arteries to supply blood to the cardiac (heart) muscle.

20. Cardiac Cycle The sequence of events that occurs when the heart beats
Two phases:
Diastole – Ventricles are relaxed, lower pressure
Systole – Ventricles contract, higher pressure

22. Diastole During this portion of the cycle, the ventricle is relaxed
The atrioventricular valves are open
The pulmonary valve and the aortic valve are closed
The ventricles fill with blood – right is deoxygenated and the left is oxygenated
The atria contract filling the ventricles until the pressure is greater than in the blood vessels

23. Systole Ventricles have contracted
The atrioventricular valves have closed
The aortic and pulmonaric valves are opened
Blood rushes from the ventricles to the aorta and pulmonary arteries

25. Fun Facts The heart beat is strong enough to squirt blood 30 feet
The longer a boy’s ring finger is, the less likely they are to suffer a heart attack
The human heart beats ~ 35 million times per year
The heart pumps ~ 1 million barrels of blood in a lifetime
Most heart attacks occur between 8 – 9 a.m.

26. Fun Facts
The blue whale has the largest heart – it weighs one ton (approximately)
The hummingbird heart beat is 1000 times per minute
Your entire blood volume goes through your entire body once every minute
Humans have ~ 60, 000 miles of blood vessels in their bodies
Pig and baboon hearts have been transplanted into humans

28. Blood direction
DEOXYGENATED Superior vena cava and inferior vena cava  Right Atrium  through the tricuspid valve  Right Ventricle  through the aortic valve  the Pulmonary arteries  TO THE LUNGS OXYGENATED Pulmonary veins  Left Atrium  through the mitral valve  Left Ventricle  through the aortic valve  Aorta  to every cell of the body  back to the vena cava!! Full Circle!