1. It Keeps On Beating Name of PowerPoint Name of Course Name of Lesson
Project Lead The Way©
Copyright 2005

2. Review! What Does the Cardiovascular System Do?
Fill in the Blanks: (Use these terms) temperature, hormones, oxygen, carbon dioxide, nutrients, metabolic wastes
1. Transport _____ and ______ to all cells.
2. Remove ____ and _________ from all
cells.

3. Cardiovascular Jobs 3. Circulate _______ for chemical regulation.
4. Help maintain body __________.

4. Cardiac Cycle One complete sequence of pumping and filling
Contraction phase is called systole
Relaxation phase is called diastole
Average adult at rest completes 75 cardiac cycles per minute or 0.8 seconds per cycle

5. What Makes the Heart Beat?
Caused by electrical impulses:
SA Node (sinoatrial node)
Pacemaker
Sets timing and rhythm of heart beat
Sends electrical impulse similar to nerve impulse
Triggers cells of both atria to contract in unison
Impulse travels thorough cardiac cells to AV node (atrioventricular node)

6. What Makes the Heart Beat?
AV Node (atrioventricular node)
Located in wall between right atrium and right ventricle
Delays spreading the electrical impulses for 0.1 seconds to ensure the atria are completely empty
Sends impulses to specialized muscle fibers and Purkinje fibers, which conduct signal to apex of heart and induce ventricular contraction

7. What Makes the Heart Beat?
Electrical Activity