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Unformatted text preview: ll tissues. 10 Pulmonary Circulation Bulk flow follows Poiseuille's equation for hydrodynamic flow. Therefore, changes in pressure driving forces (either hydrostatic or osmotic) and in the size of "pores" or intercellular clefts will alter exchange. Contraction of capillary endothelial cells by substances such as histamine and bradykinin increases intercellular pore size and greatly augments fluid and electrolyte movement by increasing the capillary filtration constant. There is some evidence that vesicles can fuse together creating pores across endothelial cells (c in preceding figure). Vesicular Transport Vesicular transport is involved in the translocation of macromolecules across capillary endothelium (b in preceding figure). Active Transport Some molecules (e.g., ions, glucose, amino acids) can also be taken up by vascular endothelial cells by transport mechanisms; however, this is not normally thought of as a mechanism for exchange between plasma and interstitium, but rather between an individual cell and its surrounding extracellular e...
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This note was uploaded on 04/18/2008 for the course PHYS 1010 taught by Professor Thompson during the Fall '07 term at New York Medical College.
- Fall '07
- Hydrostatic Pressure