Chapter 21, part 2

1. Chapter 21, part 2 Blood Vessels and Circulation

2. Arterial blood pressure • Arterial blood pressure • Maintains blood flow through capillary beds • Rises during ventricular systole and falls during ventricular diastole • Pulse is a rhythmic pressure oscillation that accompanies each heartbeat • Pulse pressure = difference between systolic and diastolic pressures Mean arterial pressure (MAP)

3. Figure 21.10 Pressures within the Cardiovascular System Figure 21.10

4. Figure 21.10 Pressures within the Cardiovascular System Figure 21.10

5. Capillary Exchange • Flow of water and solutes from capillaries to interstitial space • Plasma and interstitial fluid are in constant communication • Assists in the transport of lipids and tissue proteins • Accelerates the distribution of nutrients • Carries toxins and other chemical stimuli to lymphoid tissues

6. Processes that move fluids across capillary walls • Diffusion • Filtration • Hydrostatic pressure (CHP) • Reabsorption

7. Figure 21.12 Capillary Filtration Figure 21.12

8. Figure 21.12 Capillary Filtration Figure 21.12

9. Forces acting across capillary walls • Capillary hydrostatic pressure (CHP) • Blood colloid osmotic pressure (BCOP) • Interstitial fluid colloid osmotic pressure (ICOP) • Interstitial fluid hydrostatic pressure (IHP)

10. Filtration and reabsorption • Processes involved in filtration and reabsorption include • Net hydrostatic pressure • CHP - IHP • Net colloid osmotic pressure • BCOP - ICOP

11. Figure 21.13 Forces Acting across Capillary Walls Figure 21.13

12. Venous pressure and venous return • Assisted by two processes • Muscular compression • The respiratory pump PLAY Animation: Factors that Affect Blood Pressure

13. SECTION 21-3Cardiovascular Regulation

14. Cardiovascular Regulation • Autoregulation • Neural mechanisms • Endocrine mechanisms

15. Autoregulation of blood flow within tissues • Local vasodilators accelerate blood flow in response to: • Decreased tissue O2 levels or increased CO2 levels • Generation of lactic acid • Release of nitric acid • Rising K+ or H+ concentrations in interstitial fluid • Local inflammation • Elevated temperature

16. Figure 21.14 Homeostatic Adjustments that Compensate for a Reduction in Blood Pressure and Blood Flow Figure 21.14

17. Figure 21.14 Homeostatic Adjustments that Compensate for a Reduction in Blood Pressure and Blood Flow Figure 21.14

18. Neural Mechanisms • Adjust CO and PR to maintain vital organ blood flow • Medullary centers of regulatory activity include • Cardiac centers • Vasomotor centers control • Vasoconstriction via adrenergic release of NE • Vasodilation via direct or indirect release of NO

19. Reflex control of cardiovascular function • Baroreceptors reflexes monitor stretch • Atrial baroreceptors monitor blood pressure • Chemoreceptor reflexes monitor CO2, O2, or pH levels PLAY Animation: Autoregulation and Capillary Dynamics

20. Figure 21.15 Baroreceptor Reflexes of the Carotid and Aortic Sinuses Figure 21.15

21. Figure 21.16 The Chemoreceptor Reflexes Figure 21.16

22. Hormones and cardiovascular regulation • Antidiuretic hormone – released in response to decreased blood volume • Angiotensin II – released in response to a fall in blood pressure • Erythropoietin – released if BP falls or O2 levels are abnormally low • Natriuretic peptides – released in response to excessive right atrial stretch

23. Figure 21.17 The Regulation of Blood Pressure and Blood Volume Figure 21.17a

24. Figure 21.17 The Regulation of Blood Pressure and Blood Volume Figure 21.17b