Download Chapter 15

THIRD EDITION
HUMAN PHYSIOLOGY
AN INTEGRATED APPROACH
Dee Unglaub Silverthorn, Ph.D.
Chapter 15
Blood Flow and the Control
of Blood Pressure
PowerPoint® Lecture Slide Presentation by
Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
The Blood Vessels and the Cardiovascular System
• Arteries: blood from heart
• Strong & Elastic
• Conduct blood to capillaries
• Sphincters
• Capillaries: exchange with cells
• Veins
• Return blood to heart
• Valves
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Arteries
endothelium
Smooth muscle cell layer
adventitia
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Veins
“Blood Reservoir”
70% of our blood volume
is on the venous side.
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The Blood Vessels and the Cardiovascular System
Figure 15-1: Functional model of the cardiovascular system
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• ARTERIES
• ARTERIOLES (pressure variability)
• METARTERIOLES (pressure variability)
• CAPILLARIES (microcirculation; low pressure)
• VENULES (microcirculation; low pressure)
• VEINS
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Make Up of Blood Vessels: Arteries and Arterioles
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Figure 15-2: Blood vessels
Metarterioles
• Bypass
capillaries
• Large cells
• Speed flow
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Figure 15-3: Metarterioles
Blood Pressure:
Generated by Ventricular Contraction
• Pulsatile: surges in arteries
• Elastic rebound evens & maintains pressure
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Blood Pressure:
Generated by Ventricular Contraction
Figure 15-4: Elastic recoil in the arteries
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Blood Pressure (BP): Measurements
• "Blood pressure"
• Systolic over diastolic
• About 120/80 mmHg
• Sphygmomanometer
• "Estimate of pressure"
• Korotkoff sounds
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More Blood Pressures:
Pulse and Mean Arterial Pressures
Figure 15-5: Pressure throughout the systemic circulation
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More Blood Pressures:
Pulse and Mean Arterial Pressures
• Pulse pressure is the strength of the pulse wave.
• Pulse pressure = Systolic–Diastolic
• Mean arterial pressure is an estimate of
ventricular pressure.
• Mean arterial pressure (MAP) = Diastolic +
1/3 pulse p
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Blood Pressure (BP): Measurements
Figure 15-7: Measurement of arterial blood pressure
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Arteriole Resistance: Control of Local Blood Flow
• Myogenic auto regulation
• Paracrines:
• Active hyperemia
• Reactive hyperemia
• Sympathetic nerves – CNS
• Not lecturing on it; but you are responsible for
this information.
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Capillary Blood Flow:
Greatest Total Cross Sectional Area
• Lowest Velocity
• Hydrostatic
pressure drops
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Figure 15-17: The velocity of flow depends on the total crosssectional area
Capillary Exchange:
• Filtration; leaves capillary
• Absorption; enters capillary
• Plasma (inside capillary)
• Interstitial fluid or ECF (outside capillary)
• Colloid osmotic pressure
• Created by proteins in the plasma (constant)
• Hydrostatic pressure- like holes in a garden hose.
• Decreases from artery to venous side!!!
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Capillary Exchange:
Colloidal Osmotic Pressure is Constant
Figure 15-18a: Fluid exchange at the capillary
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Net Out Flow Into ECF
• Net filtration – net absorption = net out flow
• About 2 L/day collected by lymph vessels
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Figure 15-18b: Fluid exchange at the capillary
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
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Figure 15-18a: Fluid exchange at the capillary
Lymphatic System: Structure and Roles (overview)
• Lymphatic structures
• Capillaries with valves
• Lymph vessels
• Lymph nodes & organs
• Immune defense
• Transport of fats
• Collects excess ECF
• Returns to plasma
• Edema
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Lymphatic System: Structure and Roles (overview)
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Figure 15-19: The lymphatic system
Lymph Node; Immune function
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Edema; increase in hydrostatic pressure
Abnormal
swelling
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Regulation of Blood Pressure
• Medullary cardiac control center
• Baroreceptor reflex
• Carotid
• Aortic
PLAY
Animation: Cardiovascular System: Blood Pressure Regulation
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Regulation of Blood Pressure
Figure 15-22: The baroreceptor reflex: the response to increased blood pressure
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