Vascular Registry Review Question and answer rated A+What do arteries transport?
gases, nutrients, and other essential substances to
... [Show More] capillaries.
Arterioles are considered what type of vessel?
resistance vessels; which assist with regulating blood flow through contraction and relaxation.
What are capillaries?
where nutrients and waste products are exchanged between tissue and blood.
What are the job of venules?
to carry blood out of capillary beds
What does the tunica intima consist of?
surface layer or smooth endothelium base membrane, and connective tissue
What layer of the arterial wall causes vasodilatation and vasoconstriction?
Tunica media
What does the tunica media consist of?
smooth muscle and elastic tissue
What does the tunica externa (adventitia) consist of?
fibrous connective tissue and muscle fibers (thinner than media)
What does the adventitial layer contain?
vasa vasorum (tiny vessels that carry blood to the walls or the larger arteries.
What is cardiac output?
Volume of blood ejected by the heart in one minute:
cardiac output = heart rate x stroke volume
Movement of any fluid medium between two points requires two things:
1. a pathway where fluid can move
2. pressure differential
Resistance and flow rate are inversely or directly related?
inversely;
lower resistance, higher flow rate
higher resistance, lower flow rate
Total energy is the sum of what?
Potential, kinetic, and gravitational energy
How much hydrostatic pressure is at the ankles? (supine)
0 mmHg against the arteries and veins at the ankles.
What is inertia?
The tendency of fluid to resist a change in velocity
(Ex. body at rest remains at rest)
Elevated hemocrit does what to blood viscosity (blood thickness)?
increases
Severe anemia does what to blood viscosity?
decrease
Poisuelle's law defines relationship between:
pressure, volume, and resistance
-helps define how much fluid volume moves through vessel
The law of conservation of mass explains?
the relationship between velocity and area
Ex: Area goes up, velocity goes down
-Anuerysm low velocity
-Stenosis high velocity
What are some regions where flow separations may occur?
reverse flow, stagnant flow, little movement, bypass graft anastomosis site, valve cusp site, curved vessels
The reversal component of a high resistant signal may disappear distal to a stenosis because of
decreased peripheral resistance, secondary to ischemia.
Doppler flow distal to a significant stenosis is
Lower resistant.
In addition it's more rounded in appearance and is weaker in strength.
What is autoregulation?
the ability of most vascular beds to maintain constant level of blood flow over a wide range of perfusion pressures.
What happens if autoregulation is not present?
perfusion pressure drops below a critical level
What happens to resistance vessels when BP rises?
constriction
What happens to resistance vessels when BP falls?
dilatation
Cross sectional area reduction of 75%= a diameter reduction of how much?
50%
A hemodynamically significant stenosis causes what?
A notable reduction in volume flow and pressure.
Proximal to a stenosis:
Flow frequencies are usually dampened, with or without disturbances.
ENTRANCE into stenosis produces an increase in Doppler shift frequencies (DSF), resulting in:
spectral broadening and elevated velocities
FLOW DISTURBANCE occurs due to:
high velocities & eddy currents
Abnormal "jet" (elevated velocities) may be isolated to:
area of stenosis, but also approaching and/or leaving it.
At stenosis exit, what occurs near edge of flow pattern?
flow reversals, flow separations, eddy currents
What are the 6 P's of acute arterial occlusion?
Pallor (or mottling)
Pain
Paresthesia
Polar (cold)
Pulselessness
Paralysis (or weakness/muscle spasms)
What are possible causes of acute arterial disease?
thrombus, emboli, trauma [Show Less]