1. Chapter 5 The Cardiovascular System

2. Key Concepts

3. artery arteriovenus anastomoses (AV shunts)arteriovenus anastomoses (AV shunts) arterioles atrium atrioventricular (AV) nodeatrioventricular (AV) node autorhythmicity blood flow blood pressure cardiac contractilitycardiac contractility cardiac cycle cardiac output (CO)cardiac output (CO) cardiac reserve

4. diastole dynamic exercise end diastolic volume (EDV)end diastolic volume (EDV) end systolic volume (ESV)end systolic volume (ESV) ephatic conduction exercise intensity Fick method Frank-Starling law of the heartFrank-Starling law of the heart heart murmur indicator dilution method maximum heart rate (HRmax)maximum heart rate (HRmax) non-pathologic cardiac hypertrophynon-pathologic cardiac hypertrophy

5. pathologic cardiac hypertrophypathologic cardiac hypertrophy pressure gradient pulmonary veins reserve of heart rate resistance vessels resting heart rate sinoatrial (SA) node static exercise stroke volume (SV)stroke volume (SV) stroke volume reservestroke volume reserve systole vagus nerve veins ventricles venules

6. Review Questions

7. On the following diagram of the heart, what do A through K refer to? A. B. C. D. E. F. G. H. I. J. K. Atria (Left/Right) Superior vena cava Inferior vena cava Pulmonary veins Pulmonary artery Aorta Ventricle (Left/Right) Right (AV) valve Left (AV) valve Aortic valve C A A B B D E F G H I J Pulmonary valve K

8. Describe the heart as two pumps. The right heart pumps blood to the lungs, where the blood is oxygenated. The left heart pumps the oxygenated blood to the systemic circulation.

9. Describe the different kinds of blood vessels. Arteries –carry blood away from the heart and toward the tissues Veins –carry blood from the tissues back to the heart Pulmonary veins –carry oxygenated blood from the lungs to the left heart to be pumped out into the systemic circulation Arterioles – are muscular vessels that keep the pressure low in the capillaries Capillaries –are thin-walled vessels through which gases, nutrients, and waste products are exchanged Venules –are very small vessels that connect capillaries to veins

10. In the following diagram of the conducting system of the heart, what are A through G? A. B. C. D. E. F. G. Sinoatrial (SA) node Atrioventricular (AV) node Bundle of His Bundle branches (Left/Right) Purkinje system Superior vena cava Internodal pathways A B C D E F G

11. What occurs during diastole? The ventricles fill with blood

12. What occurs during systole? The ventricular muscle contracts to force blood out of the chambers of the ventricles.

13. What is the purpose of heart valves? Valves create unidirectional blood flow. After blood passes through them, they close, preventing the backflow of blood.

14. What is the formula for determining cardiac output? CO=HR x SV, where HR is heart rate and SV is stroke volume.

15. What is the Fick method of estimating CO? Determining the rate at which oxygen is added to the blood as it flows through the lungs. This results in an estimation of pulmonary blood flow, which is equal to CO.

16. What is the indicator dilution method of determining the CO? Involves injecting dye into a large vein or the right atrium. The concentration of the dye as it passes through an artery is recorded and the CO is estimated from this information.

17. What is the role of vagus fibers on the heart rate? They have an inhibitory influence on the SA node, so they decrease the heart rate.

18. What is the role of sympathetic fibers on the heart rate? They have a stimulatory influence on the SA node, so they increase the heart rate.

19. What are the 9 factors that affect heart rate? Why? 1.Age 2.Gender 3.Size 4.Posture 5.Ingestion of food 6.Smoking 7.Emotion 8.Body temperature 9.Heat and humidity heart rate decreases with age resting heart rate of women is faster than men in general, heart rate is inversely related to size the change from lying down to standing up increases heart rate resting heart rate is higher following a meal significantly increases heart rate increases heart rate heart rate increases as body temp. increases heart rate increases in hot weather

20. Name four factors that affect stroke volume. Why? Gravity Muscular activity Size of the heart Nervous influences Can cause blood to pool in the lower extremities, decreasing venous return. Contracting muscles put pressure on veins, causing blood to be shunted toward the heart. Larger hearts contract more forcefully than smaller ones. Regular exercise trains the nervous system to respond more efficiently to the demands of the exercise.

21. Name three reasons why heart rate is more important than stroke volume in aerobic exercise. 1.Stroke volume levels out at approximately eight times the resting level 2.Heart rate is proportional to the work load imposed 3.Heart rate is proportional to the oxygen consumed

22. What are the stages of typical heart rate response to exercise? 1.At the beginning of exercise, the heart rate rises rapidly. For light or moderate exercise, a plateau is reached within the first minute. For vigorous exercise, the heart rate increases until exhaustion. 2.At the end of exercise, the heart rate rapidly declines within the first two or three minutes. 3.After the initial rapid decline, the rate decreases more slowly.

23. What differences in exercise affect heart rate? 1.Static vs. dynamic exercise 2.Intensity of the exercise 3.Duration of the exercise

24. How does heart rate respond to static and dynamic exercise? Only a slight increase in heart rate occurs during static exercise, whereas large increases in heart rate can occur during dynamic exercise.

25. Name three ways training affects the heart. Decreases resting heart rate and heart rate during exercise Increases stroke volume Increases cardiac reserve capacity

26. How does aerobic exercise affect blood pressure? Aerobic exercise elevates systolic pressure but has little effect on diastolic pressure.

27. How does isometric exercise affect blood pressure? The intrathoracic pressure dramatically increases, decreasing venous return to the right atrium and putting a greater load on the heart.

28. Cardiac patients and older adults should avoid aerobic exercise. True or False? False. Isometric exercise puts a much heavier load on the heart and should be avoided for these people.

29. Useful Websites

30. Cardiovascular system www.innerbody.com/image/cardov.html American Heart Association www.americanheart.org The Heart.Org Cardiology Online www.theheart.org/index.cfm AACVPR—American Association of Cardiovascular and Pulmonary Rehabilitation www.aacvpr.org Anatomy and Physiology of the Cardiovascular System www.mercksharpdohme.com/disease/heart/coronary_health/anatomy /home.html

31. Selected Images

32. Figure 5.1 Basic anatomy of the heart.

33. Figure 5.2 The conducting system of the heart. The impulse is initiated at the SA node and travels to the AV node, bundle of His, bundle branches, and Purkinje fibers.

34. Figure 5.4 The one-way valves of the veins. Contraction of the surrounding skeletal muscle aids in the movement of blood toward the heart, and the valves prevent blood from moving away from the heart.

35. Figure 5.6 The microcirculation.