Understanding the Cardiovascular System: Heart & Blood

1. Heart & Blood

2. Cardiovascular System • Blood • Heart • Blood vessels • Arteries - bring blood away from heart • Veins – bring blood to heart • Capillaries – smallest vessels where oxygen/nurtrient exchange occurs

3. Heart Wall • Located in the mediastinum within the thoracic cavity (pericardial cavity) • Protected by serous membrane called pericardium • Epicardium – forms outermost layer of cardiac wall • Myocardium – composed of cardiocytes • Endocardium – thin layer that covers chambers of heart

5. Myocardium

6. External Anatomy of the Heart • Four chambers  2 ventricles , 2 atria • Atria: “receiving” chambers and return blood from veins • Ventricles: “pumping” chambers and distribute blood to lungs and tissues • Pulmonary circuits  directs deoxygenated blood to lungs • Systemic circuit  takes oxygenated blood to the body

7. Carotid Brachiocephalic Subclavian Vena Cava Aorta Pulmonary Arteries Pulmonary Trunk Pulmonary Veins Left Atrium Semilunar Valves & Aortic Valve Right Atrium Bicuspid/Mitral Valve Tricuspid/AV Valve Left Ventricle Right Ventricle

9. https://www.youtube.com/watch?v=X_R8-S5bEYo

10. Coronary Circulation • The heart can NEVER completely rest • It needs to nourish itself • Systemic circulation  coronary circulation: supplies myocardium with oxygen for muscle contraction

11. Left Coronary Artery Circumflex Artery Right Coronary Artery Marginal Artery Anterior IV Branch Posterior IV Branch

14. Coronary Circulation cont’d • The arteries are circulating oxygenated blood • Cardiac veins collect the deoxygenated blood from myocardium • Veins merge at the coronary sinus • Empties deoxygenated blood into the right atrium

15. How can the heart contract? • Cardiac muscle tissue is “autorhythmic” • Does NOT need stimulation from nerves • Brain only dictates how fast the heart contracts • Pacemaker  Sinoatrial node (SA node) • Sets the pace by sending an electrical impulse to other nodal cells SA Node AV Node

16. Blood Pressure • Pressure of the circulating blood against your vessel walls • Systolic – when heart contracts and pushes through arteries • Diastolic – measures pressure when ventricles are filling up / in between beats • Normal is about 120/80 • Hypertension  silent killer

17. Let’s Talk About Blood….

18. Composition and Function • Regulates pH and electrolyte levels • Supplies cells with nutrients and oxygen • Manufacture substances needed for defense against bacteria • Ability to change from liquid to gel in clot formation for injury repair • Classified into: • Formed elements • Plasma

20. Formed Elements • Red blood cells (erythrocytes)  oxygen transport via hemoglobin • White blood cells (leukocytes)  phagocytes, scavenger cells that destroy foreign substances • Eosinophils • Basophils – release histamine • Platelets  injury mediators / blood clotting • Normal bleeding time 0-7 min

21. White Blood Cells

25. Hematocrit • Equivalent to the RBC concentration in the blood • Used to determine possible anemia • Can you still be anemic with a normal RBC concentration? • Yes

26. Hemoglobin • RBC protein responsible for oxygen transport • Measuring the hemoglobin can give you information on oxygen carrying capacity of the blood

27. Cholesterol is carried in the blood • Atherosclerosis: disease in which blood vessels become increasingly occluded or blocked by plaques • High cholesterol levels can lead to atherosclerosis • Normal value: is 130-200 mg per 100 ml of blood • Good vs Bad Cholesterol • HDL vs LDL

28. How does high cholesterol affect the heart?

29. Blood Pressure • Pressure of the circulating blood against your vessel walls • Systolic – when heart contracts and pushes through arteries • Diastolic – measures pressure when ventricles are filling up / in between beats • Normal is about 120/80 • Hypertension  silent killer

31. RhoGAM