Hemodynamics Flashcards
Define compliance in terms of hemodynamics
aka distensibility
The degree in which a vessel responds to pressure/volume
arteries=higher pressure
veins=higher volumes
Define elasticity in terms of hemodynamics
the ability of the vessel to stretch AND recoil
Define axial/driving pressure in terms of hemodynamics
the pressure driving blood forward
Define radial pressure in terms of hemodynamics
the pressure exerted ACROSS the walls of the vessels
Define hydrostatic pressure in terms of hemodynamics
aka intravascular pressure
the pressure generated by blood on the vessel walls
Define flow in terms of hemodynamics
VOLUME/unit time
Define velocity in terms of hemodynamics
DISTANCE/unit time
What is vascular resistance
measure of how difficult to make blood flow through the vessels
What are the two ways we can change blood flow
- change in pressure
2. change in resistance
What has the greatest impact on vascular resistance
radius
decrease in radius causes 4x increase in resistance
How does a change in vessel diameter affect velocity and volume
If diameter decreases=velocity increases , volume decreases
If diameter increases= velocity decreases, volume decreases
True or False Cross-sectional area is inversely proportional to velocity
True
What vessels have the slowest velocity and why
Capillaries have the slowest velocities b/c there cross sectional area is the largest of any vessel
What vessels have the fastest velocity and why
The large vessels b/c there cross sectional area is the smallest of any vessel
Describe laminar flow
flow at the center of a vessel is greatest in the center and slowest at the walls
Vascular disease is characterized by what kind of flow
turbulent flow (whorls, vortices, eddies)
What are the variables that influence blood flow velocity and pressure in the body
- Cardiac output
- Vascular resistance
- Vessel compliance
- Blood Volume
- Blood Viscosity
- Blood vessel length and diameter
How does cardiac output affect blood flow
increase cardiac output (SVxHR) increases flow
-so anything that increases SV or HR increases flow
How does compliance affect blood flow
Decrease compliance causes increased resistance which decreases flow
How does blood volume affect blood flow
decrease volume =decrease flow
increase volume=increase flow
How does blood viscosity affect blood flow
increase viscosity=decrease flow
decrease viscosity=increased flow
How does vessel length affect blood flow
increased length=decreased flow
decreased length=increased flow
How does vessel diameter affect blood flow
increased diameter=decreased flow
decreased diameter= increased flow
