1. Blood Flow and the Control of Blood Pressure15

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

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

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

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

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

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

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

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

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

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

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