Blood Flow and the Control of Blood Pressure 15

About this Chapter The blood vessels Blood pressure Resistance in the arterioles Distribution of blood to the tissues Exchange at the capillaries The lymphatic system Regulation of blood pressure Cardiovascular disease

Functional Model of the Cardiovascular System Figure 15-1

Blood Vessel Structure PLAY Animation: Cardiovascular System: Anatomy Review: Blood Vessel Structure & Function Figure 15-2

Metarterioles Capillaries lack smooth muscle and elastic tissue reinforcement which facilitates exchange Figure 15-3

Angiogenesis New blood vessel development Necessary for normal development Wound healing and uterine lining growth Controlled by cytokines Mitogens: VEGF and FGF Inhibit: angiostatin and endostatin Coronary heart disease Collateral circulation

Elastic Recoil in Arteries Ventricular contraction Ventricle contracts. Aorta and arteries expand and store pressure in elastic walls. Semilunar valve opens. Arterioles 1 2 3 Figure 15-4a

Elastic Recoil in Arteries Ventricular contraction Ventricle contracts. Arterioles 1 Figure 15-4a, step 1

Elastic Recoil in Arteries Ventricular contraction Ventricle contracts. Semilunar valve opens. Arterioles 1 2 Figure 15-4a, steps 1–2

Elastic Recoil in Arteries Ventricular contraction Ventricle contracts. Aorta and arteries expand and store pressure in elastic walls. Semilunar valve opens. Arterioles 1 2 3 Figure 15-4a, steps 1–3

Elastic Recoil in Arteries (b) Ventricular relaxation Isovolumic ventricular relaxation occurs. Elastic recoil of arteries sends blood forward into rest of circulatory system. Semilunar valve shuts, preventing flow back into ventricle. 1 2 3 Figure 15-4b

Elastic Recoil in Arteries (b) Ventricular relaxation Isovolumic ventricular relaxation occurs. 1 Figure 15-4b, step 1

Elastic Recoil in Arteries (b) Ventricular relaxation Isovolumic ventricular relaxation occurs. Semilunar valve shuts, preventing flow back into ventricle. 1 2 Figure 15-4b, steps 1–2

Elastic Recoil in Arteries (b) Ventricular relaxation Isovolumic ventricular relaxation occurs. Elastic recoil of arteries sends blood forward into rest of circulatory system. Semilunar valve shuts, preventing flow back into ventricle. 1 2 3 Figure 15-4b, steps 1–3

Review of Blood Flow

Pressure throughout the Systemic Circulation Blood pressure is highest in the arteries and decreases continuously as it flows through the circulatory system Figure 15-5

Blood Pressure Pulse Pressure = systolic P – diastolic P Valves ensure one-way flow in veins MAP = diastolic P + 1/3(systolic P – diastolic P) PLAY Animation: Cardiovascular System: Measuring Blood Pressure

Measurement of Arterial Blood Pressure Figure 15-7

Blood Pressure Mean arterial pressure is a function of cardiac output and resistance in the arterioles Figure 15-8

Blood Pressure Blood pressure control involves both the cardiovascular system and the renal system Figure 15-9

Factors that Influence Mean Arterial Pressure PLAY Animation: Cardiovascular System: Factors That Affect Blood Pressure Figure 15-10