1. Cardiovascular System
The Heart

2. The Cardiovascular System
A closed system of the heart and blood vessels
The heart pumps blood
Blood vessels allow blood to circulate to all parts of the body
The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

3. Systemic Circulation – delivers blood to all body cells and carries away waste
Pulmonary Circulation – eliminates carbon dioxide and oxygenates blood (lung pathway)

4. The distal end of the heart is called the apex.
Structure of the Heart
About the size of a fist.
Located in the mediastinum (space between lungs, backbone, sternum), between the 2nd rib and the 5th intercostal space.
The distal end of the heart is called the apex.

6. Protective Coverings of the Heart
Fibrous Pericardium encloses the heart and has 2 layers
Visceral pericardium (inner)
Parietal pericardium (outer, attached to diaphragm, sternum and vertebrae)
Pericardial cavity contains fluid for the heart to float in and reduces friction

7. Wall of the Heart Epicardium – outer layer, reduces friction
Myocardium – middle layer, mostly cardiac muscle
Endocardium – thin inner lining, within chambers of the heart

8. Heart Chambers & Valves
Your heart is a double pump. Circulation is a double circuit: Pulmonary (lungs only) and systemic (rest of the body)
Heart has 4 chambers:
2 Atria – thin upper chambers that receive blood returning to the heart through veins. Right and Left
2 Ventricles – thick, muscular lower chambers. Receive blood from the atria above them. Force (pump) blood out of the heart through arteries. Right and left
Septum – separates the right and left sides of the heart

9. Valves of the Heart Allow one-way flow of blood
4 total—2 Atrioventricular Valves (AV) & 2 Semilunar valves
Left Atrioventricular valve – also called the bicuspid valve or mitral valve. Between left atrium and ventricle
Right Atrioventricular valve – also called the tricuspid valve. Between right atrium and ventricle
Aortic Semilunar – or just aortic valve. Between the left ventricle and the aorta
Pulmonary Semilunar, or just pulmonary valve. Between the right ventricle and the pulmonary trunk

10. The cusps (flaps) of the bicuspid and tricuspid valves are anchored to the ventricle walls by fibrous “cords” called chordae tendineae, which attach to the wall by papillary muscles. This prevents the valves from being pushed up into the atria during ventricular systole.

11. Mitral = bicuspid (left side) Tricuspid (right side)
Aortic and Pulmonary are both semilunar valves

13. Blood Flow Through the Heart
Blood that is low in oxygen and high in CO2 enters right atrium through the superior and inferior vena cavae
From (contraction) right atrium, through the tricuspid valve, blood travels to the right ventricle
From (contraction) the right ventricle, blood leaves the heart as it passes through the pulmonary semilunar valve into the pulmonary trunk
Pulmonary trunk splits into right and left pulmonary arteries that carry blood to the lungs

14. Blood Flow Through the Heart
5. Oxygen is picked up and carbon dioxide is dropped off by blood in the lungs
6. Oxygen-rich blood returns to the heart through the four pulmonary veins
7. Blood enters the left atrium and travels through the bicuspid (mitral) valve into the left ventricle
8. From the left ventricle, (wall contracts) blood leaves the heart via the aortic semilunar valve and aorta
9. Oxygenated blood flows to all body tissues

15. Path of Blood Flow

16. Heart Contractions
Contraction is initiated by the sinoatrial node (SA node)
Sequential stimulation occurs at other autorhythmic cells, forcing cardiac muscle depolarization in one direction—from atria to ventricles
Once SA node starts the heartbeat
Impulse spreads to the AV node
Then the atria contract
At the AV node, the impulse passes through the AV bundle, bundle branches, and Purkinje fibers
Blood is ejected from the ventricles to the aorta and pulmonary trunk as the ventricles contract

17. 1. Sinoatrial node (Pacemaker) 2. Atrioventricular node 3
1. Sinoatrial node (Pacemaker) 2. Atrioventricular node 3. Atrioventricular Bundle (Bundle of His) 4. Left & Right Bundle branches 5. Bundle Branches (Purkinje Fibers)