1. Chapter 15a Blood Flow and the Control of Blood Pressure

2. 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

3. Figure 15-1 Functional Model of the Cardiovascular System Elastic arteries Aorta Aortic valve Left heart Right heart Lungs Left ventricle Right ventricle Left atrium Right atrium Pulmonary veins Pulmonary artery Pulmonary valve Tricuspid valve Capillaries Mitral valve Venae cavae Venules Arteriole with variable radius Exchange of material with cells Expandable veins

4. Blood Vessel Structure Figure 15-2

5. Blood Vessel Structure & Function PLAY Interactive Physiology® Animation: Cardiovascular System: Anatomy Review: Blood Vessel Structure & Function

6. Metarterioles Regulate Flow into Capillary Beds Capillaries lack smooth muscle and elastic tissue reinforcement, which facilitates exchange Figure 15-3 Collateral arteries Arteriole wall is smooth muscle. Metarterioles can act as bypass channels. Vein Venule Capillaries Arteriovenous bypass Precapillary sphincters Small venule

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

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

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

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

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

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

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

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

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

16. Review of Blood Flow Table 15-1

17. 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

18. 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 Interactive Physiology® Animation: Cardiovascular System: Measuring Blood Pressure

19. Cuff pressure > 120 mm Hg Stethoscope Cuff pressure between 80 and 120 mm Hg Cuff pressure < 80 mm Hg Inflatable cuff Pressure gauge (a) (b) (c) Measurement of Arterial Blood Pressure Figure 15-7

20. Blood Pressure Mean arterial pressure is a function of cardiac output and resistance in the arterioles Figure 15-8 Elastic arteries Arterioles Left ventricle Mean arterial pressure Cardiac output Variable resistance Mean arterial pressure  cardiac output  resistance

21. Blood Pressure Blood pressure control includes rapid responses from the cardiovascular system and slower responses by the kidneys

22. Blood volume Blood pressure leads to triggers Compensation by cardiovascular system Vasodilation Cardiac output Excretion of fluid in urine blood volume Blood pressure to normal Compensation by kidneys Stimulus Integrating center Tissue response Systemic response Slow responseFast response KEY Blood Pressure Figure 15-9

23. Factors that Influence Mean Arterial Pressure Figure 15-10

24. Factors that Influence Mean Arterial Pressure PLAY Interactive Physiology® Animation: Cardiovascular System: Factors That Affect Blood Pressure