C- Hemodynamics & Vasculature Flashcards
________ is Highest in aorta.
Pressure
Pressure decreases through system, especially in resistance vessels (sm arteries & arterioles)
Pressure is_______ in capillaries and venous system
low
Total blood volume ~ 5 L
Largest volume in _______(“capacitance vessels”)
veins
Q = DP/R
this represents?
Q = DP/R
Pressure differences (ΔP) drive blood flow (Q). Vascular resistance (R) opposes blood flow.
volume per unit time (ml/min)
CONSTANT through system (since closed loop)
CARDIAC OUTPUT (CO) = Total flow in the cardiovascular system
Flow (Q)
distance per unit time (cm/sec)
v=Q/A (flow/cross sectional area)
Velocity highest in aorta (lowest total cross-sectional area), lowest in capillaries (greatest cross-sectional area).
Velocity (v)
CO = (Pa-Pv)/TPR
Cardiac Output
Pa = mean arterial blood pressure Pv = venous blood pressure TPR = total peripheral resistance
Variation of flow equation: Q=DP/R
_______ is the volume of blood pumped per minute by the heart (~5 L/min at rest)
Cardiac Output (CO) CO = (Pa-Pv)/TPR
___________ corresponds to the total flow in cardiovascular system
Cardiac Output
CO = (Pa-Pv)/TPR
Flow is proportional to 4th power of radius. Thus ___________ is the biggest determinant of flow.
radius of vessel
Flow is proportional to ____________. Thus radius of vessel is the biggest determinant of flow.
4th power of radius
resistance of a parallel network is ________ than the resistance of any single vessel
lower
*Changing the resistance of a single vessel has little effect on the system
Total resistance of a series of vessels is _________ than the resistance of any individual vessel
higher
*Resistances in series are additive
(flow)
Most efficient
Velocity fastest in center, zero at edge
Flow equation assumes this flow. Not true in CV system
Laminar flow
(flow)
Irregular, with eddies and vortices
Less efficient – requires more pressure to achieve same velocity
Promoted by large diameter, high velocity, low viscosity, changes in diameter, and irregularities on walls
Turbulent flow
*Turbulent flow produces shearing forces that can damage vascular endothelium
Heartbeat produces _____ flow in aorta, but _____ flow requires more work. dampened in arterial system.
pulsatile
FLOW IS __________IN CAPILLARIES
CONTINUOUS
Systolic pressure =
peak aortic pressure
Diastolic pressure =
minimum aortic pressure
Blood pressure is expressed as
systolic/diastolic = ex 120/80 mmHg
Vessels lose compliance with age =
arteriosclerosis
Compliance represents the elastic properties of vessels (or chambers)
arteriosclerosis results in
Older people have higher systolic pressure and higher pulse pressure than younger people
Tension in wall increases as pressure and radius increase.
Walls of larger vessels subject to greater tension.
________ increases stress on walls of vessels and chambers.
Hypertension
Law of LaPlace:
Relationship between wall tension & transmural pressure
