1 / 43

Blood Flow and Blood Pressure Control

Explore the intricate mechanisms of arteriolar resistance, hormonal influence, capillary exchange, and the lymphatic system in regulating blood flow and pressure. Dive into the dynamics of fluid exchange, baroreceptor reflexes, and cardiovascular control.

vickies
Download Presentation

Blood Flow and Blood Pressure Control

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Blood Flow and the Control of Blood Pressure 15

  2. Arteriolar Resistance • Sympathetic reflexes • Local control of arteriolar resistance • Hormones

  3. Arteriolar Resistance

  4. Arteriolar Resistance • Myogenic autoregulation • Paracrines • Active hyperemia • Reactive hyperemia • Sympathetic control • SNS: norepinephrine • Adrenal medulla: epinephrine

  5. Hyperemia Figure 15-11a

  6. Hyperemia Figure 15-11b

  7. Norepinephrine Tonic control of arteriolar diameter Figure 15-12

  8. Distribution of Blood Distribution of blood in the body at rest Figure 15-13

  9. Blood Flow Blood flow through individual blood vessels is determined by vessel’s resistance to flow Figure 15-14a

  10. Blood Flow Blood flow through individual blood vessels is determined by vessel’s resistance to flow Flow  1/resistance Figure 15-14b

  11. Precapillary Sphincters Figure 15-15a

  12. Precapillary Sphincters Figure 15-15b

  13. Capillaries: Exchange • Plasma and cells exchange materials across thin capillary wall • Capillary density is related to metabolic activity of cells • Capillaries have the thinnest walls • Single layer of flattened endothelial cells • Supported by basal lamina • Bone marrow, liver and spleen do not have typical capillaries but sinusoids

  14. Two Types of Capillaries Figure 15-16a

  15. Two Types of Capillaries Figure 15-16b

  16. Velocity of Blood Flow Velocity of flow depends on total cross-sectional area of the vessels Figure 15-17

  17. Capillary Exchange • Exchange by paracellular pathway or transendothelial transport • Small dissolved solutes and gasses by diffusion is determined by concentration gradient • Large solutes and proteins by vesicular transport • In most capillaries, large proteins are transported by transcytosis

  18. Capillary Exchange • Bulk flow • Mass movement as result of hydrostatic or osmotic pressure gradients • Absorption: fluid movement into capillaries • Net absorption at venous end • Filtration: fluid movement out of capillaries • Caused by hydrostatic pressure • Net filtration at arterial end

  19. Fluid Exchange at a Capillary Hydrostatic pressure and osmotic pressure regulate bulk flow PLAY Animation: Cardiovascular System: Autoregulation and Capillary Dynamics Figure 15-18a

  20. Lymphatic System • Returning fluid and proteins to circulatory system • Picking up fat absorbed and transferring it to circulatory system • Serving as filter for pathogens

  21. Fluid Exchange at a Capillary Figure 15-18b

  22. Lymphatic System Figure 15-19

  23. Edema • Two causes • Inadequate drainage of lymph • Filtration far greater than absorption • Disruption of balance between filtration and absorption • Increase in hydrostatic pressure • Decrease in plasma protein concentration • Increase in interstitial proteins

  24. Blood Pressure KEY Medullary cardiovascular control center Stimulus Sensor/receptor Integrating center Efferent pathway Change in blood pressure Effector Parasympathetic neurons Carotid and aortic baroreceptors Sympathetic neurons SA node Ventricles Veins Arterioles Components of the baroreceptor reflex Figure 15-21

  25. Blood Pressure KEY Stimulus Sensor/receptor Integrating center Efferent pathway Change in blood pressure Effector Figure 15-21 (1 of 10)

  26. Blood Pressure KEY Stimulus Sensor/receptor Integrating center Efferent pathway Change in blood pressure Effector Carotid and aortic baroreceptors Figure 15-21 (2 of 10)

  27. Blood Pressure KEY Medullary cardiovascular control center Stimulus Sensor/receptor Integrating center Efferent pathway Change in blood pressure Effector Carotid and aortic baroreceptors Figure 15-21 (3 of 10)

  28. Blood Pressure KEY Medullary cardiovascular control center Stimulus Sensor/receptor Integrating center Efferent pathway Change in blood pressure Effector Parasympathetic neurons Carotid and aortic baroreceptors Figure 15-21 (4 of 10)

  29. Blood Pressure KEY Medullary cardiovascular control center Stimulus Sensor/receptor Integrating center Efferent pathway Change in blood pressure Effector Parasympathetic neurons Carotid and aortic baroreceptors Sympathetic neurons Figure 15-21 (5 of 10)

  30. Blood Pressure KEY Medullary cardiovascular control center Stimulus Sensor/receptor Integrating center Efferent pathway Change in blood pressure Effector Parasympathetic neurons Carotid and aortic baroreceptors Sympathetic neurons SA node Figure 15-21 (6 of 10)

  31. Blood Pressure KEY Medullary cardiovascular control center Stimulus Sensor/receptor Integrating center Efferent pathway Change in blood pressure Effector Parasympathetic neurons Carotid and aortic baroreceptors Sympathetic neurons SA node Figure 15-21 (7 of 10)

  32. Blood Pressure KEY Medullary cardiovascular control center Stimulus Sensor/receptor Integrating center Efferent pathway Change in blood pressure Effector Parasympathetic neurons Carotid and aortic baroreceptors Sympathetic neurons SA node Ventricles Figure 15-21 (8 of 10)

  33. Blood Pressure KEY Medullary cardiovascular control center Stimulus Sensor/receptor Integrating center Efferent pathway Change in blood pressure Effector Parasympathetic neurons Carotid and aortic baroreceptors Sympathetic neurons SA node Ventricles Arterioles Figure 15-21 (9 of 10)

  34. Blood Pressure KEY Medullary cardiovascular control center Stimulus Sensor/receptor Integrating center Efferent pathway Change in blood pressure Effector Parasympathetic neurons Carotid and aortic baroreceptors Sympathetic neurons SA node Ventricles Veins Arterioles Figure 15-21 (10 of 10)

  35. Blood Pressure The baroreceptor reflex: the response to increased blood pressure Figure 15-22

  36. Blood Pressure The baroreceptor reflex: the response to orthostatic hypotension PLAY Animation: Cardiovascular System: Blood Pressure Regulation Figure 15-23

  37. CVD: Risk Factors • Not controllable • Gender • Age • Family History • Controllable • Smoking • Obesity • Sedentary lifestyle • Untreated hypertension

  38. CVD: Risk Factors • Uncontrollable genetic but modifiable lifestyle • Blood lipids • Leads to atherosclerosis • HDL-C versus LDL-C • Diabetes mellitus • Metabolic disorder contributes to development of atherosclerosis

  39. LDL and Plaque The development of atherosclerotic plaques Figure 15-24

  40. Hypertension The relationship between blood pressure and the risk of developing cardiovascular disease Essential hypertension has no clear cause other than hereditary Figure 15-25

  41. Hypertension • Carotid and aortic baroreceptors adapt • Risk factor for atherosclerosis • Heart muscle hypertrophies • Pulmonary edema • Congestive heart failure • Treatment • Calcium channel blockers, diuretics, beta-blocking drugs, and ACE inhibitors

  42. Summary • Blood vessels • Vascular smooth muscle, metarterioles, venules, and angiogenesis • Measuring blood pressure • Systolic pressure, diastolic pressure, pulse pressure, MAP, and Korotkoff sounds • Resistance in the arterioles • Myogenic autoregulation, active hyperemia, and reactive hyperemia

  43. Summary • Distribution of blood • Capillary exchange • Continuous capillaries, fenestrated capillaries, bulk flow, filtration, absorption, and colloid osmotic pressure • Lymphatic system • Blood pressure regulation • Baroreceptors, baroreceptor reflex, and cardiovascular control center • Cardiovascular disease

More Related