L25: Regional Circulations

The contractile state of a resistance vessel is the vessel _____.

tone

_____ is the state of partial contraction independent of metabolic and neural mechanisms.

basal tone

_____ results from the intrinsic properties of the vessel vascular smooth muscle.

basal tone

During ______, most resistance vessels are constricted somewhat more than basal due to tonic sympathetic nerve activity.

resting state

The _____ maintains the pressure gradient for blood flow.

heart

Differences in blood flow to each organ are due to differences in ______.

vascular resistance

______ mechanisms are independent of neural and hormonal mechanisms.

intrinsic

______ mechanisms use hormonal or neural control.

extrinsic

Active hyperemia, autoregulation, and reactive hyperemia are all _____ mechanisms.

intrinsic

Through ______, blood flow to a tissue is maintained constant over a physiological range of perfusion pressures.

autoregulation

During ______, blood flow is adjusted to meet the metabolic demands of a tissue.

active hyperemia

During active hyperemia, as the rate of metabolism increases, blood flow _____.

increases

During active hyperemia, metabolites cause vasorelaxation and a decrease in ______.

resistance

______ is the increase in blood flow to a tissue that occurs in response to transient ischemia.

reactive hyperemia

The _____ is tight junctions between endothelial cells that prevent circulating vasoactive substances from affecting cerebral blood flow.

blood brain barrier