1. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 12 Lecture Slides

2. Learning Outcomes Anatomy of the Heart 1. Identify the protective coverings of the heart. 2. Identify the parts of the heart and describe their functions. Cardiac Cycle 3. Describe the events of the cardiac cycle. 4. Trace the flow of blood through the heart. Heart Conduction System 5. Identify parts of the heart conduction system and describe their functions.

3. Learning Outcomes Regulation of Heart Function 6. Explain how the heart rate is regulated. Types of Blood Vessels 7. Describe the structure and function of arteries, arterioles, capillaries, venules, and veins. 8. Describe how materials are exchanged between capillary blood and interstitial fluid. Blood Flow 9. Describe the mechanism of blood circulation.

4. Learning Outcomes Blood Pressure 10. Compare systolic and diastolic blood pressure. 11. Describe how blood pressure is regulated. Circulation Pathways 12. Compare the systemic and pulmonary circuits. Systemic Arteries 13. Identify the major systemic arteries and the organs or body regions that they supply.

5. Learning Outcomes Systemic Veins 14. Identify the major systemic veins and the organs or body regions that they drain. Disorders of the Heart and Blood Vessels 15. Describe the common disorders of the heart and blood vessels.

6. Heart and blood vessels are part of the cardiovascular system Heart pumps blood Arteries carry blood away from the heart to capillaries Veins carry blood from capillaries to heart

7. 12.1 Anatomy of the Heart Four chambered muscular pump Lies between the lungs, superior to the diaphragm Pointed apex extends to left side at level of 5th rib

9. Protective Coverings –Pericardium surrounds the heart and associated blood vessels –Parietal and visceral pericardia are serous membranes Secrete serous fluid into pericardial cavity Functions to reduce friction during contraction

10. –Parietal and visceral pericardia are serous membranes Secrete serous fluid into pericardial cavity Functions to reduce friction during contraction

11. The Heart Wall –Myocardium Layer of cardiac muscle Provides force for contraction –Epicardium (visceral pericardium) Outer most layer Contains blood vessels that nourish the heart –Endocardium Inner layer

12. Heart Chambers –2 atria Receive blood from veins –2 ventricles Pump blood to arteries –Interventricular septum

13. –Heart is a double pump Left atria and ventricle: left pump Right atria and ventricle: right pump

14. –Differences in wall thickness depend upon work performed by the chamber Ventricles have more muscle then atria: atria pump to ventricle, ventricles pump out to body areas Left ventricle is most muscular: pumps blood to body Right ventricle has less muscle: pumps blood to lungs only

16. Heart Valves –Blood flows in one direction through the heart due to valves –Atrioventricular valves Prevents backflow Tricuspid valve: between R atrium and R ventricle Bicuspid valve (or mitral valve): between L atrium and L ventricle

17. –Semilunar valves Pulmonary semilunar valve: between R ventricle and pulmonary trunk Aortic semilunar valve: between L ventricle and aorta

19. 12.2 Cardiac Cycle Includes: –Systole: contraction phase –Diastole: relaxation phase

20. Flow of Blood Through the Heart –Two basic circuits of blood flow Pulmonary circuit –Deoxygenated blood flows from R ventricle to lungs –Oxygenated blood flows from lungs to L atrium Systemic Circuit –Oxygenated blood flows L ventricle to body –Deoxygenated blood flows from body to R atrium

21. Steps of heart circulation –Superior and inferior vena cava return blood from body to R atrium –Pulmonary veins return blood from lungs to R atrium –Atria push blood into ventricles –R ventricle pumps blood into pulmonary trunk Blood moves into R and L pulmonary arteries, which head to lungs –L ventricle pumps blood into the aorta, which carries blood out to body

23. 12.3 Heart Conduction System Conduction system consists of specialized muscle tissue that acts as neural tissue –Spontaneously form impulses –Impulses cause myocardium to contract

24. Components include –Sinoatrial (SA) node –Atrioventricular (AV) node –AV bundle –Purkinje fibers

25. Sinoatrial node –Pacemaker of the heart –Rhythmically forms impulses to initiate each heartbeat –Impulses cause simultaneous contraction of atria

26. Atrioventricular node –Receives impulse from SA node –Delay in passing through node allows time for ventricular filling and the completion or atrial contraction –Passes impulse to the AV bundle

27. AV bundle –Divides into L and R branches –Carries impulse down ventricular septum and up lateral ventricle walls –Forms Purkinje fibers Purkinje fibers –Carry impulse to myocardium of ventricles –Contraction occurs from the apex upward

28. Electrocardiogram (ECG or EKG) –Recording of the electrical current generated during heart contraction –Performed by an electrocardiograph

29. –Electrocardiogram has three distinct waves P wave: atrial depolarization QRS wave: ventricular depolarization T wave: ventricular repolarization

30. Other factors affecting heart rate –Age: resting rate declines with age –Sex: females slightly faster than males –Physical condition: good condition means lower heart rate

31. –Temperature: increase in temperature increases rate –Epinephrine: increases strengthens heart rate –Thyroxine: produces a lesser but longer lasting increase in heart rate

32. –Blood calcium levels Low levels slow heart rate Increased levels increase heart rate and prolong contraction –Blood potassium levels Increased layers decrease both heart rate and force of contraction Low levels can cause abnormal heart rhythms

33. Arteries –Carry blood away from the heart –Branch into smaller arteries, eventually forming arterioles Play an important role in controlling blood flow and blood pressure

34. 12.7 Blood Pressure Arterial blood pressure in the systemic circuit –Systolic blood pressure Highest pressure during ventricular systole –Diastolic blood pressure Lowest pressure during ventricular diastole

35. Factors Affecting Blood Pressure –Cardiac output Volume of blood pumped by heart in one minute –Determined by heart rate and blood volume pumped in contraction Increase cardiac output, increase blood pressure Decrease cardiac output, decrease blood pressure

36. –Blood volume Decrease in blood volume, decrease in blood pressure Increase in blood volume, increase in blood pressure –Peripheral resistance Friction of blood against blood vessel walls Constriction of arterioles increase both resistance and blood pressure Dilation of arterioles decreases both resistance and blood pressure

37. 12.11 Disorders of the Heart and Blood Vessels Grouped into –Heart disorders –Blood vessel disorders

38. Heart Disorders Arrhythmia –Abnormal heart beat –Caused by factors such as damage to conduction system and drugs

39. –Includes: Bradycardia –Heart rate less then 60 beats/min Tachycardia –Heart rate over 100 beats/min Heart flutter –Heart rate over 200-300 beats/min Fibrillation –Very rapid heart rate with uncoordinated contraction –Blood is not pumped from ventricles

40. Congestive heart failure (CHF) –Acute or chronic inability of hear to pump out returned to it –Symptoms include fatigue, edema, accumulation of blood in organs –Possible cause is atherosclerosis Heart murmurs –Unusual heart sounds associated with defective heart valves

41. Myocardial infarction –Death of myocardium due to coronary artery blockage –Heart attack Pericarditis –Inflammation of pericardium due to viral or bacterial infection

42. Blood Vessel Disorders Aneurysm –Weakened vessel wall bulges, forming balloon-like sac filled with blood –Rupture can be fatal

43. Arteriosclerosis –Hardening of the arteries –Due to calcium deposits accumulating in tunica media Atherosclerosis –Formation of fatty deposits in the tunica interna of arteries –Plagues reduce lumen size and increase probability of blood clot formation

44. Hypertension –Chronic high blood pressure –Pressure exceeds 140/90 –Pre-hypertension A systolic pressure between 120-139 and diastolic pressure between 80-89 –Causes include stress and smoking

45. Phlebitis –Inflammation of a vein –Most common in the legs –Thrombophlebitis involves the formation of blood clots at the inflammation site Varicose veins –Dilated, swollen veins due to malfunctioning valves –Causes include heredity, pregnancy, and lack of physical activity –Hemorrhoids