1. Heartbeat regulation

2. Heartbeat - SA Node Sinoatrial node (SA) = Pacemaker
Small group of cardiac muscle cells
Starts the wave of heart muscle contraction
“Sets the pace”

3. Heartbeat - AV Node Atrioventricular node (AV) Bundle of fibers
Picks up impulses from the SA node and transmits to network of fibers in the ventricles

4. Regulation of the Heartbeat
YouTube Video
Regulation of the Heartbeat

5. Disorders of the Circulatory System

6. Disorders of the Circulatory System - Atherosclerosis
Fatty deposits in walls of arteries
Obstruct blood flow and raise blood pressure
Increase risk of blood clots

7. Disorders of the Circulatory System - Heart Attack
Caused by blocked arteries
Blood cannot get to the heart muscle
Heart muscle begins to die due to lack of O2

8. Disorders of the Circulatory System - Stroke
Blood clot breaks free and blocks a vessel leading to the brain
Brain cells starved of O2 and nutrients
May cause paralysis, loss of ability to speak or death

9. Disorders of the Circulatory System - High Blood Pressure
Blood pressure is the measure of force exerted by the blood on the wall of the arteries
Too much pressure can cause health problems such as heart disease

10. STOP HERE!

11. Heartbeat Heartbeat depends on body’s need for oxygen-rich blood
Increase heart beat:
Sympathetic nervous system
Decrease heart beat:
Parasympathetic nervous system