血管生理. Hemodynamics w Blood flow: flow velocity is related to total cross-sectional area (sum...
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Transcript of 血管生理. Hemodynamics w Blood flow: flow velocity is related to total cross-sectional area (sum...
Hemodynamics Blood flow:
flow velocity is related to total cross-sectional area (sum of total cross sections of all capillaries Laminar flow Turbulent flow
Blood flow through vessels depends on the pressure gradient and vascular
F=P/R F:flow rate of blood through a vessel P: pressure gradient R: resistance of blood vessels
Arterial system As a conduit for blood between the heart
and capillaries as a preeusure reservoir for forcing blood
into the small-diameter arterioles dampen oscillations in pressure and flow control distribution of blood to different
capillary network
Blood pressure Measurement direct method indirect method systolic pressure diastolic pressure pulse pressure
Arteriole The major resistance vessels control of distribution of
blood flow
pressure drop from 97 mmHg to 37 mmHg
Arteriolar tone Vasoconstriction↑
Myogenic activity ↑oxygen ↓carbon dioxide and other metabolites ↑sympathetic stimulation, ADH, AII. Cold
Vasodition ↓ myogenic activity ↓ Oxygen ↑ CO2 and other metabolites ↑adenosine release ↓ sympathetic stimum, histamine release, heat endothelial-derived relaxing factor (EDRF) such as NO