Flashcards in Exam 1 Deck (614)
A small change in vessel diameter causes enormous change in:
Conductance of a vessel increases in proportion to the _________________________________.
4th power of the diameter
What is Poiseuille's law?
F = pie (change) P r^4/ 8nl
Poiseuille's law is related to :
In Poiseuille's law, diameter plays the greatest role in determining rate of
In systemic circulation: 2/3 of resistance to flow is ___________________ resistance
Strong mm walls of arteriole so can change ____________________________. Which can increase blood flow up to __________-fold
diameter up to fourfold
Viscosity has an inverse relationship to ____________________.
% of blood that consists of cells
(hematocrit = 40)
many cells in the blood
Who has more hematocrit, males or females??
The theory of circulatory function addresses the needs of tissues that tightly controls blood flow; small-tissue specific vessel dilate or constrict locally to control:
flow in addition to change in cardiac output
Cardiac output primarily controlled by:
some of all local tissue flows
In general, arterial pressure is controlled independently of:
local blood flow or cardiac output
DBP + (pp/3)
PP (partial pressure) =
SBP - DBP
Mean arterial pressure (MAP) =
pressure that propels blood to tissues
Pulse pressure (pp) =
affected by SV and compliance of "arterial tree"
Difference between SBP and DBP. Normally about 1/3 of SBP.
MAP and PP decrease with:
increasing distance from heart
Mean pressure ~0mmHg at:
mean pressure at capillaries =
mean pressure of pulmonary circulation =
What is the difference b/n MAP and Mean pressure?
What are 3 effects of pressure on blood flow?
1. increases force on blood flowing through vessels
2. distends vessel
3. what are the effects of vessel distension
Distension linty: veins ____ arteries
veins > arteries
Compliance = capacitance =
total quantity of blood that can be stored in a given portion of the circulation for each mmHg pressure rise
compliance = distensibility X :
Central venous pressure =
right atrial pressure ~0mmHg
venous pressure influences on ____________________
R atrial pressure