3. The Human Heart Unit X

4. Heart Action Controlled by ANS: Medulla Beats per minute: 70/80 (normal)

5. Heart Action Cont. Blood cycle: One minute Blood loss: 35% Serious 50% Fatal

6. Heart Action Cont. Factors that affect heart rate: Age Weight Physical condition Emotional State Gender

7. Heart Contractions Four chambered heart Atria (atrium): Contract first Ventricle(s): Contract second “All or None Law”

8. Heart Contraction Cont. Vagus nerve Sinoatrial node: “SA node” “Pacemaker of Heart” Regulates heartbeat Atrialventricular node: “AV node” “Bundle of His”

9. Atria Ventricles SA node AV node Bundle of His Heart Contraction: Impulse Transmission

10. Heart Cont. Composition: Cardiac muscle Location: Pericardial cavity Pericardium (membrane) Pericardial fluid

11. Heart Cont. Heart structure* Blood flow* (Overhead)

12. Blood Vessels Veins: Carry blood to heart High in CO 2 3 tissue layers One-way valves

13. Blood Vessels Cont. Arteries: Carry blood away from heart High in O 2 3 tissue layers (much thicker)

14. Blood Vessels Cont. Capillaries: Connect arteries to veins Gas exchange

15. Blood Vessels Cont. Coronary Arteries & Veins: Supply the heart

16. Blood Pressure Two types: Systolic* Diastolic*

17. Systolic Contraction of ventricles Range: 90-140 mmHg (120 average)

18. Diastolic Ventricles relax (atria fill) Range: 60-90 mmHg (80 average)

19. Blood Pressure Cont. Major causes of high blood pressure: Heart attack Stroke (most common problem)

20. High Blood Pressure Factors Age Weight Emotions Physical cond. Diet Arteriosclerosis Blood viscosity Blood volume Cardiac output Gender

21. General Review 60,000-100,000 miles Heparin Hemophilia Streptokinase Epinephrine-serotonin Heart cells (size, not #)

22. That’s All Folks!! Quiz Tomorrow