1. Bell ringer
Why does our heart need to have fluid surrounding it?

2. Cardiovascular System: The Human Heart

3. EQ
What are the different structures of the heart that allow it to pump blood throughout our bodies?
FOCUS: external layers of the heart and heart wall.

4. The Human Heart Located between the lungs in thoracic cavity
Pointed end called apex
Acts as a pump to propel blood through the body
Approximately 2/3 of its mass is on the left side of the body
Heart is about the size of your closed fist

5. Layers of the heart Outer Membrane Pericardium
Heart Wall ( from outside to inside)
Epicardium
Myocardium
Endocardium

6. Pericardium Membrane that surrounds and protects the heart
Made of two layers:
Fibrous Pericardium
Serous Pericardium

7. Fibrous Pericardium (Outer)
Outer layer of the pericardium
Tough, dense, inelastic connective tissue
Prevents stretching of the heart
Provides protection
Anchors heart in place

8. Serous Pericardium (Inner)
Thin membrane
Forms a double layer around the heart
Parietal Layer (outer layer)
Visceral Layer (inner layer)
Same as epicardium
Pericardial Cavity
Between parietal and visceral layer
Contains pericardial fluid -> reduces friction between membranes as heart moves

9. Heart Wall Epicardium Myocardium
also visceral layer of serous pericardium
Thin transparent outer layer of the heart wall
Myocardium
Consists of cardiac muscle tissue -> only found in the heart
Makes up the bulk of the heart
Responsible for pumping action of the heart

10. Heart Wall Endocardium
Thin epithelial layer that lines the inside of the heart
Covers the valves and tendons inside the heart
Continuous with epithelial lining of large blood vessels

11. Parts of the Heart

12. The Heart: Chambers Right and left side act as separate pumps
Four chambers
Atria
Receiving chambers
Right atrium
Left atrium
Ventricles
Discharging chambers
Right ventricle
Left ventricle
Figure 11.2c

13. Blood Circulation
Figure 11.3

14. The Heart: Valves Allow blood to flow in only one direction
Four valves
Atrioventricular valves – between atria and ventricles
Bicuspid valve (left)
Tricuspid valve (right)
Semilunar valves between ventricle and artery
Pulmonary semilunar valve
Aortic semilunar valve

15. The Heart: Valves Valves open as blood is pumped through
Held in place by chordae tendineae (“heart strings”)
Close to prevent backflow

16. The Heart: Associated Great Vessels
Aorta
Leaves left ventricle
Pulmonary arteries
Leave right ventricle
Vena cava
Enters right atrium
Pulmonary veins (four)
Enter left atrium