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Chapter 15 The Cardiovascular System Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Cardiovascular System Components • • • • Heart: Pump Arteries, Arterioles: Distribution system Capillaries: Exchange vessels Veins: Collection and return system Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition The Heart • Myocardium – Striated lattice-like network – Functions as a unit Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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 Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition The Arterial System • AortaArteriesArterioles • Vessels have endothelial tissue, smooth muscle, and connective tissue. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Blood Pressure • Pressure generated by the pumping action of the heart and the resistance of the blood vessels • BP = Cardiac output × Total peripheral resistance Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Blood Pressure • Systole – Contraction phase • Diastole – Relaxation phase Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Blood Pressure Measurement • Auscultation method – Listen for Korotkoff sounds. – Use a stethoscope and sphygmomanometer. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Mean Arterial Pressure • MAP = Diastolic BP + [0.333 (Systolic − Diastolic)] • Reveals information regarding workload of the heart Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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. • • • • Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Blood Flow in Capillaries • Precapillary sphincters regulate flow. • Capillaries open and flow increases during exercise. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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 Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Venous Pooling • Muscle pump – Prevents pooling and edema – Directs blood back towards the heart Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Hypertension • Chronically elevated blood pressure > 140 / 90 mm Hg • Imposes a strain on the CV system • It is a prevalent disorder. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Effective Treatment • • • • • • Medications Regular physical activity Weight loss Stress management Decreased sodium intake Decreased alcohol consumption Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition BP Response to Exercise • Resistance exercise – Straining compresses vessels. – Peripheral resistance increases. – Blood pressure increases in an attempt to perfuse tissues. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Effects of Impaired Blood Supply • Impaired flow usually results in angina pectoris. • If flow is severely reduced, myocardial infarction may result. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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 Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Myocardial Metabolism • Myocardium has a significantly higher mitochondrial density compared with skeletal muscle. • This allows the heart to utilize – Glucose – Fatty acids – Lactate Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Myocardial Metabolism • Endurance exercise training increases the ability to use lactate and fatty acids for fuel. • Decrease reliance on CHO Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition