1. Blood Flow and the Control of Blood Pressure
Chapter 15, part B
Blood Flow and the Control of Blood Pressure

2. Arteriole Resistance: Control of Local Blood Flow
Myogenic auto regulation
Paracrines:
Active hyperemia
Reactive hyperemia
Sympathetic nerves – CNS

3. Arteriole Resistance: Control of Local Blood Flow
PLAY
Animation: Cardiovascular System: Autoregulation and Capillary Dynamics
Figure 15-11: Hyperemia

4. Distribution of Blood in the Body Organs
Responds to metabolic need
Precapillary sphincters
Local & CNS regulators
Huge variations (example: skeletal m 20-85%)

5. Distribution of Blood in the Body Organs
Figure 15-13: Distribution of blood in the body at rest

6. Capillary Blood Flow: Greatest Total Cross Sectional Area
Lowest Velocity
Hydrostatic pressure drops
Figure 15-17: The velocity of flow depends on the total cross-sectional area

7. Capillary Exchange: Colloidal Osmotic Pressure is Constant
Proteins stay in capillary
Water, oxygen, glucose – move out
CO2, N wastes, water – move in
Bulk flow out on arterial side, in on venous side
PLAY
Animation: Cardiovascular System: Autoregulation and Capillary Dynamics

8. Capillary Exchange: Colloidal Osmotic Pressure is Constant
Figure 15-18a: Fluid exchange at the capillary

9. Net Out Flow Into ECF Net filtration – net absorption = net out flow
About 2 L/day collected by lymph vessels
Figure 15-18b: Fluid exchange at the capillary

10. Capillary Exchange: Hydrostatic Pressure Declines
High on arterial side – bulk flow out
Low on venous side – bulk flow in
Fenestrations &/or leaky joints speed exchange
Figure 15-18a: Fluid exchange at the capillary

11. Lymphatic System: Structure and Roles (overview)
Lymphatic structures
Capillaries with valves
Lymph vessels
Lymph nodes & organs
Immune defense: lymphocytes
Transport of fats
Collects excess ECF
Returns to plasma
Edema
PLAY
Animation: Fluids & Electrolytes: Electrolyte Homeostasis

12. Lymphatic System: Structure and Roles (overview)
Figure 15-19: The lymphatic system

13. Regulation of Blood Pressure
Medullary cardiac control center
Baroreceptor reflex
Carotid
Aortic
Kidney: blood volume
Hypothalamus & Cortex: stress, blushing, etc.
PLAY
Animation: Cardiovascular System: Blood Pressure Regulation

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

15. Cardiovascular Diseases: #1 killer
Risk Factors:
Smoking
Obesity
Diabetes
Genes
Diseases:
Hypertension
Stroke
"Heart Attack"

16. Mechanism of Atherosclerosis
LDL build up
Plaque
 Flow
Rupture
Clot
Blocked flow
Tissue death

17. Mechanism of Atherosclerosis
Figure 15-24: The development of atherosclerotic plaques

18. Mechanism of Atherosclerosis
Figure 15-24: The development of atherosclerotic plaques

19. Summary Blood vessels, anatomy & role in circulation
Measuring blood pressures, MAP & pulse pressure
Role of resistance in BP and distribution of blood
Autoregulation, baroreceptros, medullary cardiac control center and CNS regulation of blood pressure & distribution

20. Summary
Hydrostatic & colloidal osmotic pressures direct bulk flow in capillary exchange by diffusion, fenestrations & leaky joints
Role of lymphatic system to return excess ECF to plasma
Atherosclerosis common to several cardiovascular diseases