2. Hemodynamics Flashcards
Cardiac output from left and right sides of heart are ____, but resistance and pressure are different.
equal
What is laminar flow?
smooth, streamlined, efficient- velocity slowest at edge and fastest in the center
Turbulent flow produces shearing forces that can damage vascular endothelium, promoting the formation of ______.
thrombi and embolisms
What is pulse pressure?
systolic pressure - diastolic pressure
What is hydrostatic pressure?
blood pressure
What is the flow equation?
Q = ?P/R
More compliance in aorta = _____ .
lower pulse pressure
How do small, lipid-insoluble molecules diffuse?
through inter-endothelial junctions
What is flow equal to?
it’s constant through the system
What is pulsatile flow?
intermittent pumping that causes flow that is not constant
What determines compliance?
relative proportion of elastin fibers versus smooth muscle and collagen in vessel walls
Viscocity mostly depends on ______.
hematocrit
For O2, the rate of diffusion from capillary to tissue depends on ______ and on ______.
the distance btw the capillary and the tissue; on the amount of O2 carried in blood
Explain v = Q/A
velocity depends inversely on cross-sectional area (A)
Where is total XC area smallest? What does this result in?
in the aorta; fastest flow
______ decrease total vascular resistance.
Parallel vessels
What is Fick?s Principle?
the amount used is equal to the amount that enters the tissue minus the amount that leaves
Total resistance in a series of vessels is ____ than the resistance of any individual vessel.
higher
LaPlace’s Law is ____.
the relationship between tension in a vessel wall and the transmural pressure
What are the major determinants of oncotic pressure in the blood?
? Globulin and albumin
As viscocity increases, _____ increases and _____ decreases.
resistance; flow
Where does blood pressure fall after the aorta?
in the arterioles
Describe x = Q[x].
x is the amount of substance x, Q is the flow, and [x] is the concentration of x
Total resistance of a network of parallel vessels is _____ than the resistance of single lowest resistance vessel in the system.
lower
What is mean arterial pressure (MAP)?
~ diastolic pressure + 1/3(systolic ? diastolic)
_____ from the left and right sides of heart are equal, but resistance and pressure are different.
Cardiac output
Where is there no pulse variation?
in capillary beds
What does compliance represent?
the elastic properties of vessels or chambers of the heart
What is turbulent flow?
irregular, with eddies and vortices, requires more pressure
Flow is directly proportional to _____ and is inversely proportional to ______.
pressure; resistance
Where is total XC area greatest? What does this result in?
in the capillary beds and pulmonary circulation; slowest flow for areas of exchange
What is bulk transport?
the movement of substances through the CV system
What is velocity (v)?
distance per unit time (cm/sec)
Capillary oncotic pressure promotes ______.
REABSORPTION
Explain Flux = k[(Pc-Pi) - (πc-πi)] ** *Starling equation for transcapillary transport
Flux = net movement across capillary wall
k = constant
Pc = capillary hydrostatic pressure
Pi = interstitial hydrostatic pressure
πc = capillary oncotic pressure
πi = interstitial oncotic pressure
Why is resistance of a capillary bed so low when the pressure is so high?
there are many parallel vessels
______ is only valid for single vessels.
Poiseuille?s Law
Two opposing forces determine solvent movement: ____ and ____.
hydrostatic pressure and oncotic pressure
What is Arteriosclerosis?
loss of compliance caused by thickening and hardening of arteries
What is cardiac output (CO)?
total flow in the CV system
______ is the difference in pressure between the inside and outside of a vessel (across the wall).
Transmural pressure
Flow is ______ to pressure and is _______ to resistance.
directly ; inversely proportional
Flow varies with _____ power.
4th
As the length of the vessel increases, _____ increases and _____ decreases.
resistance; flow
What is oncotic pressure?
the osmotic force created by proteins in the blood and interstitial fluid
What is the first step in the development of atherosclerotic plaque?
damage to vascular endothelium
Explain Q = ΔP/R
Q = flow (volume/time), ΔP = pressure difference, R = resistance
Where is the highest blood pressure?
in the aorta
What is the total blood volume?
5L
Factors that increase blood pressure (ie ______) or reduce oncotic pressure (ie _____) tend to promote filtration.
hypertension; liver disease
Hydrostatic pressure promotes _____.
FILTRATION
What is transmural pressure?
the difference in pressure btw the inside and the outside of a vessel (across a wall)
Movement of blood is driven by _____ throughout the CV system.
differences in pressure
What factors increase turbulent flow?
large diameter, high velocity, low viscosity, abrupt changes in diameter, irregularities on tube walls
What is flow (Q)?
volume per unit time (mL/min)
Resistance in series is equal to?
adding the individual resistances
What drives blood flow through an organ?
the difference btw arterial and venous pressure
______ describes the relationship between tension in a vessel wall and the transmural pressure.
LaPlace?s Law
What does CO = ?
(mean arterial pressure - venous pressure)/ total peripheral resistance (TPR)
Tension in the vessel wall ______ as pressure and radius increase.
increases
Pulse pressure, mean pressure and velocity all _____ from aorta to capillaries.
decrease
_____ are more compliant than ____.
Veins; arteries
MAP depends on?
HR
_____ produces shearing forces that can damage vascular endothelium, promoting the formation of thrombi and embolisms.
Turbulent flow
Tension in the vessel wall increases as ______ increase.
pressure and radius
Cardiac output from left and right sides of heart are equal, but _____ and ______ are different.
resistance; pressure
Turbulent flow produces shearing forces that can ______, promoting the formation of thrombi and embolisms.
damage vascular endothelium
What is hematocrit? Normal for men? Women?
proportion of RBCs; 42-54% men; 38-46% women
What is compliance ( C )?
equals change in volume (?V, in ml) that results from a change in pressure (?P, in mmHg)
Radius of vessel has huge effect on flow, so doubling the radius increases flow by _____.
16-fold (24)
In the CV system, _____ is the major mechanism by which flow is controlled.
vessel diameter
Resistance in parallel is equal to?
the sum of the reciprocals of the individual resistances
