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Chapter 21
Blood Vessels and Circulation
I. The Anatomy of Blood Vessels
A. Arteries/Arterioles
B. Capillaries
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These vessels
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Form networks
Surround muscle fibers
Radiate through connective tissue
Weave throughout active tissues
Capillaries have two basic structures
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Continuous
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Fenestrated
C. Veins/Venules
II. Cardiovascular Physiology
A. Circulatory Pressure
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Circulatory pressure is divided into three components
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Blood pressure (BP)
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Capillary hydrostatic pressure (CHP)
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Venous pressure
B. Resistance (R)
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Resistance of the cardiovascular system opposes the movement of blood
For blood to flow, the pressure gradient must overcome total peripheral resistance
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Peripheral resistance (PR) is the resistance of the arterial system
C. Arterial blood pressure
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Arterial blood pressure
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Pulse is a rhythmic pressure oscillation that accompanies each heartbeat
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Mean arterial pressure (MAP)
D. Capillary Exchange
• Movement of water, gases and solutes between blood and interstitial space
1) Processes that move fluids across capillary walls
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Diffusion
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Filtration
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Hydrostatic pressure (CHP)
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Reabsorption
2) Forces acting across capillary walls
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Capillary hydrostatic pressure (CHP)
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Blood colloid osmotic pressure (BCOP)
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Interstitial fluid colloid osmotic pressure (ICOP)
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Interstitial fluid hydrostatic pressure (IHP)
3) Filtration and reabsorption
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Processes involved in filtration and reabsorption include
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Net hydrostatic pressure
• CHP - IHP
• Net colloid osmotic pressure
• BCOP - ICOP
E. Venous pressure and venous return
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Assisted by two processes
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Muscular compression
The respiratory pump