Chapter 15

1. Chapter 15 The Cardiovascular System McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

2. Cardiovascular System Components • Heart: Pump • Arteries, Arterioles: Distribution system • Capillaries: Exchange vessels • Veins: Collection and return system McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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4. The Heart • Myocardium • Striated lattice-like network • Functions as a unit McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

5. Functions of the Heart • Functions of right side • Receive blood returning from body • Pump blood to lungs for gas exchange • Functions of left side • Receive oxygenated blood from lungs • Pump blood into systemic circulation McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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7. The Arterial System • AortaArteriesArterioles • Vessels have endothelial tissue, smooth muscle, and connective tissue. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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9. Blood Pressure • Pressure generated by the pumping action of the heart and the resistance of the blood vessels • BP = Cardiac output × Total peripheral resistance McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

10. Blood Pressure • Systole • Contraction phase • Diastole • Relaxation phase McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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13. Blood Pressure Measurement • Auscultation method • Listen for Korotkoff sounds. • Use a stethoscope and sphygmomanometer. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

14. Mean Arterial Pressure • MAP = Diastolic BP + [0.333 (Systolic − Diastolic)] • Reveals information regarding workload of the heart McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

15. Capillaries • Microscopic vessels 7 – 10 m in diameter • Contain 6% of total blood volume • Walls contain one layer of epithelial cells • Skeletal muscles have a dense capillary network. • Myocardium has an even denser network. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

16. Blood Flow in Capillaries • Precapillary sphincters regulate flow. • Capillaries open and flow increases during exercise. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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19. Venous Return • One-way valves prevent back flow. • Veins serve a capacitance role. • At rest, ~ 65% of blood is on the venous side of the system. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

20. Varicose Veins • When one-way valves become defective, blood pools. • Usually occurs in surface veins • Less musculature to help compress vessels • Occurs most frequently in legs • Phlebitis • Severe varicose veins with inflammation McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

21. Venous Pooling • Muscle pump • Prevents pooling and edema • Directs blood back towards the heart McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

22. Hypertension • Chronically elevated blood pressure > 140 / 90 mm Hg • Imposes a strain on the CV system • It is a prevalent disorder. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

23. Effective Treatment • Medications • Regular physical activity • Weight loss • Stress management • Decreased sodium intake • Decreased alcohol consumption McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

24. BP Response to Exercise • Resistance exercise • Straining compresses vessels. • Peripheral resistance increases. • Blood pressure increases in an attempt to perfuse tissues. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

25. Steady-Rate Exercise • Systolic pressure increases with increases in workload. • There is a linear relationship between workload and systolic BP. • Diastolic pressure remains fairly constant. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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27. BP Response to Upper-Body Exercise • Resistance to flow is increased with upper-body exercise. • Smaller vessels in upper body compress more easily. • Care is required for individuals with heart and valve diseases. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

28. BP in Recovery • Following endurance exercise, there is a hypotensive response. • BP temporarily falls below normal resting values. • Regular exercise may help control moderate hypertension. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

29. The Heart’s Blood Supply • Coronary circulation • Right and left coronary arteries branch off the upper ascending aorta. • RCA supplies predominantly the right atrium and ventricle. • LCA supplies the left atrium and ventricle and a small portion of the right ventricle. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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31. Myocardial O2 Use • At rest, myocardium extracts ~ 70 – 80% available O2. • During exercise, flow must increase to meet O2 demand. • Flow may increase 4 – 6 times. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

32. Effects of Impaired Blood Supply • Impaired flow usually results in angina pectoris. • If flow is severely reduced, myocardial infarction may result. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

33. Rate-Pressure Product: An Estimate of Myocardial Work • Rate-Pressure Product or Double Product RPP = SBP × HR • Is a commonly used measure of myocardial work McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

34. Myocardial Metabolism • Myocardium has a significantly higher mitochondrial density compared with skeletal muscle. • This allows the heart to utilize • Glucose • Fatty acids • Lactate McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

35. Myocardial Metabolism • Endurance exercise training increases the ability to use lactate and fatty acids for fuel. • Decrease reliance on CHO McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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