1. The Heart

2. Structure of the Heart Two parallel independent systems
Two different “pumps”
atrium (auricle) & ventricle
Designating right cavity & left cavity
as if you were “wearing”
your heart

3. Heart Valve replacement

4. Function of the Cavities
Right cavity takes in oxygen poor blood from the body
Pumps it to the lungs
Left cavity takes oxygen rich blood from the lungs
Returns it to the body

5. Functions of the Cavities
Atrium draws blood in from veins
Ventricle pushes blood away through arteries

6. Differences Between the Cavities
Right cavity takes in oxygen poor blood from the body & sends it to the lungs
Left cavity takes oxygen rich blood from the lungs and sends it to the body through the aorta. Its wall is thicker because it has to pump the blood throughout the body

7. How the Heart Works There are two stages in the heart beat cycle
The diastole (relaxation)
The systole (contraction)

8. Diastole
In diastole the heart relaxes and blood goes into the two auricles
Rising pressure in each auricles opens the tricuspid and mitral valves and blood flows into the ventricles

9. Systole
Filled ventricles contract and the mitral and tricuspid valves close
The filled ventricles force the aorta and pulmonary valves to open
Blood is then pushed into the arteries

10. Rate of Heartbeat The heart is a muscle is a unique muscle.
It has the ability to contract spontaneously at a regular rate of 80 beats per minute
That is what creates the pulse

11. Rate of Heartbeat
However this rate is influenced by two nervous systems:
Sympathetic
Parasympathetic

12. Sympathetic This controls your heart by fear, and adrenaline.
For example when you get scared your heart intends to beat faster.
Your heart is also affected by exercise which is another aspect of the sympathetic nervous system

13. Parasympathetic
This nervous system controls your heart rate when you sleep
Your heartbeat is much slower when you sleep then when you are awake because of the function of this system

14. Heart Disease The major form of heart disease is atherosclerosis
In this condition fatty deposits called plaques, composed of cholesterol and fats, build up on the inner wall of the coronary arteries

15. Heart Disease
Gradual narrowing of the arteries throughout life restricts the blood flow to the heart muscles.
Symptoms of this restricted blood flow can include:
shortness of breathe
and a tightening pain in the chest

16. Heart Disease
A heart attack is caused when oxygen supply to the heart is suddenly decreased by:
plaque large enough to completely obstruct the coronary artery
when part of the plaque breaks away and lodges farther along the artery

17. How to Prevent Heart Disease
Development of fatty plaque is due to excessive intake of cholesterol and animal fat and especially cigarette smoking
Evidence suggest that physical exercise may help to prevent heart disease and watching what you eat