Components of Cardiovascular System Exercise Physiology Functions Deliver

Components of Cardiovascular System Exercise Physiology

�Functions ◦ Deliver oxygenated blood to muscles; 1900 gals/day ◦ Aerate blood in lungs ◦ Transport heat to surface ◦ Deliver nutrients to tissues ◦ Transport hormones Organization of Circulatory System

Heart Chambers Two Pumps in One � Right heart to lungs � Left heart to body � Right and left atrioventricular valves prevent backflow into atria: tricuspid-right, bicuspid (mitral)-left � Right and left semilunar valves prevent backflow into ventricles: pulmonic-right, aorticleft Circulatory System: Valves

Circulatory System: Heart

�Heart wall composed of 3 layers ◦ Epicardium ◦ Myocardium ◦ Endocardium �Differs from skeletal ◦ Intercalated discs connect cells to permit electrical transmission ◦ Homogenous muscle fibers similar to slow twitch fibers Circulatory System: Myocardium

Cardiac Cycle 1. Ventricular Diastole Ventricular filling and Atrial contraction A-V valve opens Aortic valve closes 2. Beginning of Ventricular Systole A-V valve closes, Isovolumetric Ventricular contraction Aortic valve closed 3. Ventricular Systole Ventricular ejection A-V valve closed Aortic valve opens 4. Beginning of Diastole Isovolumetric Ventricular relaxation A-V valve closed Aortic valve closes Circulatory System: Heart

Vasculature � Arteries: highly muscular, elastic � Capillaries: thin, porous single layer ◦ Capillary branching increases cross section area ◦ Flow velocity inversely proportional to area, so broad capillary beds have slow blood flow Circulatory System

Vasculature �Veins Thinner walls, less muscular Serve as blood reservoir Venous return facilitated by flaps Active cool-down facilitates blood flow Circulatory System

Blood Pressure = cardiac output x total peripheral resistance

�Systolic Blood Pressure: pressure in blood vessel due to surge of blood in aorta and subsequent recoil of aortic wall propagates a wave of pressure through circuit. �Diastolic Blood Pressure: pressure in blood vessel during diastole. �DBP provides indication of peripheral resistance or ease of flow from “a to c”. �Normal systolic BP < _? _ mm Hg and diastolic BP < _? _ mm Hg. Blood Pressure at Rest

�During RHYTHMIC exercise, increase in blood flow and dilation of blood vessels in active muscles cause SBP to __? __ and DBP to __? ___. �During RESISTIVE exercise, sustained muscular forces compress peripheral arteries causing blood pressure __? __. �Upper body exercise has ___ BP than exercise with legs. Blood Pressure during Exercise

�A bout of light- to moderate-intensity exercise decreases SBP for up to ___ hrs. �Pooling of blood in visceral organs and lower extremities reduces central blood volume which contributes to hypotensive recovery response. Blood Pressure during Recovery

�Openings for left and right coronary arteries are in aorta just above the aortic valve. �Aortic valve flaps close coronary arteries during ejection phase. Heart’s Blood Supply

�Myocardial oxygen utilization is 70% to 80% at rest, contrast to 25% other tissues. �In vigorous exercise, coronary blood flow increases 4 -6 x above normal. Heart’s Blood Supply

�Impaired coronary blood flow: angina pectoris (chest pain). �Rate pressure product: estimate of myocardial work (SBP x HR) �Myocardium almost completely aerobic Heart’s Blood Supply