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11 terms

20.3: Capillary Exchange

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Endothelial cell cytoplasm, Intercellular clefts, Filtration pores
Chemicals pass through the capillary wall by what three routes?
Diffusion, Transcytosis, Filtration, Reabsorption
What are the four mechanisms of exchange?
Diffusion
This mechanism of exchange is the most important and allows O2, CO2, and steroid hormones to travel down concentration gradient and pass through the plasma membrane; Glucose and electrolytes pass through channels, pores or clefts through this process:
Transcytosis
A process in which endothelial cells pick up material on one side of the plasma membrane and release it on the other side; Fatty acids, albumin, and some hormones, such as insulin, move across the endothelium by this method:
Filtration and Reabsorption
These two mechanisms of exchange account for fluid movement following principles of osmosis and also influenced by hydrostatic pressure:
Hydrostatic pressure
Pressure exerted by a volume of fluid against a wall, membrane, or some other structure that encloses the fluid.
Colloid Osmotic Pressure
a pulling force exerted by colloids (such as proteins, like albumin, in blood) that help maintain the water content of blood and opposes hydrostatic pressure:
Oncotic pressure
The difference between the colloid osmotic pressure of blood and of tissue fluid; tends to draw water into the capillary by osmosis, opposing hydrostatic pressures
Solvent drag
The process of "dragging" chemicals dissolved in water through the bloodstream, and pass through the capillary wall if they are not too large
Edema
The accumulation of excess fluid in a tissue is called:
Increased capillary filtration, Reduced capillary reabsorption, Obstructed lymphatic drainage
What are the three fundamental causes of edema?