1. The Heart
And how it works…

2. Heart Beats

3. Heat Beats Step 1: Enter Atrium
Right Side
Deoxygenated blood enters the right atrium through 2 large veins
Superior vena cava: upper half of the body
Inferior vena cava: below the diaphragm
Left Side
Oxygenated blood (from the lungs) enters the left atrium through the pulmonary vein
Comes from the lungs

4. Heart Beats Step 2: Contract Atrium
Blood flows from the atrium into the ventricle
The atrioventricular (AV) valve allows for a one-directional flow
The AV valve closes once the ventricle is full - LUB

5. Heart Beats Step 3: Contract Ventricle
Right ventricle contracts
Blood flows through the semilunar valve into the left pulmonary artery – DUB
Blood flows towards the lungs
Left ventricle contracts
Blood flows through the semilunar valve into the right pulmonary artery
Blood flows out towards the body

6. Path of Blood through the Heart

7. Heart Sounds Two normal heart sounds Other sounds
Lub: closure of the AV valves (beginning of ventricular contraction - systole)
Dub: closure of the semilunar valves (end of ventricular systole – diastole)
Other sounds
Heart murmur: turbulent blood flow

8. Heart Murmur: back flow

9. Overview: Blood Flow Blood in body Into heart via vena cava (vein)
Right atrium
Right Ventricle
Left pulmonary artery (deoxygenated)
Lungs (becomes oxygenated)
Pulmonary vein
Left atrium
Left ventricle
Arteries (oxygenated towards body tissue)

10. Connecting the Heart to the Lungs & the Body

11. Setting the Heart’s Tempo
Heart muscles contract without being stimulated by external nerves (myogenic muscles)
Heart muscle does not all contract at the same rhythm when separated
Heart rhythm is set by the sinoatrial (SA) node – specialized nerve cells
Nerve impulses travel to a second node AV node which sends the message toward the ventricles

12. Normal Sinus Rhythm
P wave followed by a ventricular response

13. Atrial Fibrilation
Most common arrhythmia
Result of hypertension

14. AV Block Delay in the AV node
Caused by many things but could be decreased levels of Oxygen in the blood

15. Ventricular Fibrilation
The ventricles are not contracting as a unit
There is no clear cardiac output
Commonly known as a Heart Attack

16. Flatline:
Asystole: no cardiac electrical activity (no contractions or blood flow) – cannot be treated with defibrillation