Cardiovascular System Integrates the body as a unit and provides the muscles a continuous stream of Nutrients and Oxygen AND Rapid Removal of By-products of metabolism from the site of energy release

Components Heart – 4 chambered muscular pump Arterial System –Pressure storage Capillaries Veins –Volume storage

Blood Pressure Systolic – –reflects the Work of the heart –strain against the arterial walls during ventricular contraction –120mmHg normal for rest – during vigorous activity Diastolic – –Reflects peripheral resistance the ease of blood flow from arterial to capillaries –Normal resting is 80 or below Mean pressure –is about 96mmHG

Capillaries Single layer of endothelial cells Where O2 and CO2 are exchanged 2000 – 3000 capillaries/square inch in skeletal muscle –More dense in the heart

Veins Drain deoxygenated blood back to heart via Inferior and Superior Vena Cava Next to Right Atria Then Right Ventricle To the Pulmonary –artery where it is passed through the Pulmonary Capillaries of the Lung and Oxygenated and De- Carbon di-oxygenated Pulmonary Vein to the Left Atria Back to the Left Ventricle, where it begins it circulation again.

Venous Return At rest, the venous system holds 65% of the total blood volume. Muscular contraction Smooth Muscle envelopes veins Small increases in the Tension of smooth muscle has dramatic effect on venous return –Redistributing blood to the heart

Venous Pooling Understand this concept and its significance in post exercise

Hypertension Thickening of the arterial wall –Increases the Work of the heart –Increased the peripheral resistance 1/5 American Adults have it Uncontrolled it can lead to Heart Failure and Stroke Has been shown to decrease with participation in regular aerobic exercise

Hypertension and Exercise

Efficacy of Aerobic Conditioningon lowering BP Numerous studies have supported this relationship What are the mechanism responsible for this?

BP and Exercise Resistance Exercise Steady-State Exercise What happens to systolic pressure following steady-state, submaximal, Aerobic exercise?

BP response to Graded Exercise

Cardiac Output and BP What is the relationship between these two measures?

BP and Location measured Is there any difference in pressure, depending on where they are taken –brachial artery vs. femoral artery?

Blood Supply of the Heart

Coronary Circulation Opening of the coronary arteries are located IN the aorta, just above the semi lunar valve –Right where the oxygenated blood leaves the left ventricle Coronary sinus and anterior cardiac veins –Where coronary blood drains, en route back to the right atria

Myocardial O2 Utilization % of the O2 is extracted from the coronary vessels and metabolized by the myocardium –Skeletal muscle extracts about 25% During Exercise –Profusion of the heart tissue may increase 5 times above resting levels

Myocardial Profusion during Exercise This 4-5 fold increase is accomplished via through two mechanism –Hypoxia induced by the increased myocardial metabolism This causes chemical changes that act as powerful dilatators Humoral and sympathetic also increase vasodilatation –Increased Aortic Pressure during Systole forces a greater quantity of blood into the coronary circulation.

Cardiovascular Regulation Katch Chapter 16

Intrinsic Regulation The heart has the ability to regulate its own rhythm – “inherent rythmicity” Left to be regulated ONLY on this Rythmicity, it would beat at times/minute SA node – (pacemaker) – Atria – AV Node – AV Bundle (Purkinje fibers) - Ventricles

Excitation and Conduction of the Cardiac Impulse

Electrocardiography P Wave – depolarization of the atria (.15 sec) - leads to atrial contraction QRS complex – electrical depolarization / Contraction of the ventricles T Wave – repolarization of the ventricles –Refractory period What’s going on during this period of ventricular relaxation?

Sympathetic influence –Can double the force of vent contraction –Catecholamines Act to accelerate depolarization of the SA node –tachycardia Parasympathetic influence –acetylcholine –Bradycardia effects –Vagus stimulation Training effects – read page 261- Peripheral Input Cortical Input Extrinsic Regulation

Integrated Response in Exercise