Principles of Blood Flow Flashcards
mean arterial pressure
average pressure over the entire cardiac cycle. estimated from diastolic pressure and pulse pressure.
pulse pressure
difference between systolic and diastolic pressures
systolic pressure
peak arterial pressure reached during ejection of blood by the heart
diastolic pressure
lowest arterial pressure reached during diastole when the heart is relaxed and filling with blood
dichrotic notch
small dip caused by backfilling of the aortic valve as it closes
conservation of mass
flow into a control region equals flow out if there are no sources or sinks
blood flow, Q (L/min)
quantity of blood passing a particular observation point in a given time interval.
blood flow is the same across any total cross-sectional area of the system
continuity equation
for a given constant total flow, the velocity of the bloodstream varies inversely with the total cross sectional area. for an incompressible fluid in a closed system of rigid tubes, the flows past any two total cross sectional areas must be the same at any given instant.
ratio of velocities in two parts of the system depends only on the ratio of total cross sectional areas.
transit time
time required for a blood cell to travel between two points in the system.
viscocity
related to how much the fluid resist shear forces and effects fluid flow where there are changes in velocity
flow is _____ with _____ slippage at the wall and that the viscosity is _____ across the diameter of the vessel
laminar; no; constant
major physiological variable that determines the resistance to the flow of blood
radius of the blood vessels, primarily the arterioles
Hagen-Poiseuille law
predicts the distribution of blood pressure in the various segments of the cardiovascular system.
A man has a cardiac output of
5.0 L/min or 5000 cm3/min
no slip boundary condition
fluid in contact with wall of vessel. doesn’t slide along but is resisted.
