Venous Physiology Flashcards
hydrostatic preasure
pressure within the vascular system due to the weight of a column of blood compared to a reference point
transmural pressure
the pressure on the walls of a vessel
extra- ________veins are known as ______ vessels of the body and hold about ___% of total blood vol. serving as ____ for blood.
extra-pulmonary
capacitance vessels,
65% or 2/3 total blood vol.
reservoir
veins can be ______ x larger than corresponding artery and tend to run in ____
3-4 x larger than arteries
pairs - which improves function. (blood reservior)
venous resistance refers to ?
changing of the cross sectional area of lumen which varies resistance.
elliptical cross-section shape offers high or low resistance
high
circular shape cross section and is ______ offers high or low resistance
distended ,
low
what is the most important factor effecting resistance in a vessel ?
what changes the shape of vein lumen?
radius
transmural pressure
what is the formula for resistance in a vessel
R= 8 x viscosity x length/ πr (4th power)
the ability of veins to _______ and alter resistance permits increases in blood volume with out increasing_______ to the _.
change lumen shape ,
increasing pressure gradient to the heart.
what locations in the body do veins naturally offer resistance to flow? (3)
veins collapse as they enter thorax.
subclavian veins
compressed by the first rib.
jugular veins collapse bc of atmospheric pressure
formula for hydrostatic pressure
density of blood x acceleration due to gravity x height of the column of blood in reference to r. atrium of heart
density of blood is analagous with _______-
specific gravity
HP is added to _______pressure and is related to ________-
existing circulatory pressure,
position
analogous to dynamic pressure supplied by contraction of the heart.
