Unit 2 Flashcards
What would you expect to happen to the flow when pressure increases in a vessel?
Flow would increase in a linear fashion, but not within a certain range.
Why does the flow not increase within a certain range when pressure increases? What is this called?
Tissues adjust their resistance to maintain normal blood flow.
Autoregulation
Vascular compliance equation
C = Delta V / Delta P
Change in volume / Change in transmural pressure
Amount the volume of a vessel changes in response to pressure
Vascular compliance
Term referring to the elasticity of a vessel without consideration of volume changes
Distensibility
Veins are _______ times more compliant that arteries
20 times
Why are veins more compliant than arteries
They have a greater elasticity
What causes vasoconstriction in many blood vessels
Sympathetic stimulation
Symnpathetic inhibition causes
Less pressure
Sympathetic stimulation causes
Higher pressure
True/False:
There are no parasympathetic nerves supplying the blood vessels
True
After volume increases and pressure increases, what then happens?
What is this called?
Pressure somewhat decreases as the walls stretch to accommodate the extra volume
Called Delayed compliance
2 factors that affect the pulse pressure
Stroke volume output
Compliance of the arterial tree
Pulse pressure contours:
Upstroke (due to systole)
Incisors (due to aortic valve closure)
Diastolic decline
Abnormal pressure pulse contours
Arteriosclerosis
Aortic stenosis
Patent ductus arteriosus
Aortic regurgitation
Opening in the aorta
Aortic stenosis
Hardening of the arteries, causing them to not expand
Arteriorsclerosis
Increase in systolic pressure but not much change in diastolic pressure.
Arteriorsclerosis
Aortic valve does not close so blood keeps backing up into the ventricle
Aortic regurgitation
The rising pressure in the aorta causes:
A wave of blood flow through the arterial tree
Progressive loss of pulsations upon entering the small arteries -> arterioles -> capillaries
Damping
Damping is directly proportional to:
Resistance and compliance
Pressure in the right atrium because all systemic veins flow into the right atrium
Central venous pressure
Central venous pressure is regulated by :
A balance between the ability of the right side of the heard to pump blood into the lungs, and the tendency for blood to flow into the right atrium