The Heart – Chapter 12

1. The Heart – Chapter 12 • The heart begins to beat at 4 weeks • Independent of the nervous system • In Adults it beats on average 100,000 a day • Primary function is to pump blood through the arteries, capillaries, and veins.

2. The Heart – the Anatomy • Sits between the lungs, with the bottom tip just to the left of mid-line • Enclosed in pericardial membranes • Fibrous pericardium (pericardial sac) • Serous pericardium • Parietal pericardium • Visceral pericadium

3. The Heartthe anatomy

4. The Heart – the Anatomy • The Chambers • The Vessels • The Valves

5. The Heartthe anatomy

6. The Heart – the Anatomy • The Chambers • Right Atrium – receives blood from the body • Oxygen depleted blood • The Vessels • Fed by the two large caval veins • Superior vena cava – carries blood from upper body • Inferior vena cava – carries blood from lower body • The Valves • Right atrioventricular valve – tricuspid valve

7. The Heart – the Anatomy • The Chambers • Left Atrium – receives blood from the lungs • Oxygen rich blood • The Vessels • Four pulmonary veins • Two from left lung • Two from right lung • The Valves • Mitral valve – bicuspid valve

8. The Heartthe anatomy

9. The Heart – the Anatomy • The Chambers • Right ventricle – blood comes from right atrium • Oxygen depleted blood • The Vessels • Pulmonary artery –branches to left and right lungs • The Valves • Pulmonary semilunar valve

10. The Heart – the Anatomy • The Chambers • Left ventricle – blood comes from left atrium • Oxygen rich blood • The Vessels • Aorta – Blood is pumped out to body • The Valves • Aortic semilunar valve

11. The Heartthe anatomy

12. The Heart – Cardiac Cycle • The simultaneous contraction of the two atria, followed a fraction of a second later by the simultaneous contraction of the two ventricles • Systole = contraction • Diastole = relaxation

13. The HeartCardiac Cycle

14. The Heart – Cardiac Conduction Pathway