Physiology Ans Hemodynaics Flashcards
1st left ventricle pressure exceeds that in the aorta
Pressure in the left ventricle rises rapidly
Aortic valve opens, blood is ejected, BP rises
Cardiac contraction begins:
- Left ventricle
- Aorta
- Large arteries
- Arterioles
- Capillaries
- Venules
- Large veins
- Vena cava
- Right atrium
The heart pump
Pressure is greater at the ______ gradually _______ as the blood moves further away.
Heart.
Decreasing
Each cardiac contraction distends the ___________, which serve as reservoirs for blood volume _________ and _________ supplied to the system
Arteries
Storage
Energy
Lower resistance =
Higher flow rate
Higher resistance =
Lower flow rate
Energy difference: includes losses resulting from fluid movement
Any resistance which tends to oppose such movement
The amount of flow depends
Q= A × V
Volume flow = size x speed
Increase in area
Decrease in velocity
Decrease in area
Increase in velocity
Dicrotic notch is related to the
Closure if the aortic valve
Reflects where the blood is going to.
Diastole
Reflects where the blood came from
Systole
Pulsatile changes in medium/small sized arteries of the limbs are increased. When this occurs, pulsatility changes are usually decreased in the minute arteries
Vasoconstriction
Ability to most vascular beds to maintain constant level of blood flow over wide range of perfusion pressures
Auto regulation
The amount of flow depends upon:
Enegery difference
Any resistance
Includes losses resulting from fluid movement
Enegery difference
Which tends to oppose such movement
Any resistance
A __________ _________ is needed to move blood from one point to another.
Enegery gradient
The larger the gradient
Greater the flow
Relates to the tendency of a fluid to resist changes in its velocity
Inertia
Energy continually restored by
Pumping action of heart
As the blood moves farther out to periphery
Energy dissipated largely in the form of heat
Movement of a fluid (blood) is dependent upon
Physical properties of the fluid and what its moving through
Elevated hematocrit increases
Blood viscosity
Severe anemia decreases
Blood viscosity
Increase viscosity
Decrease velocity
Decrease viscosity
Increase velocity
Diminishing vessel size increases
Frictional forces and heat energy losses
Laminar flow is considered
Stable flow
Likely seen at vessel origin. As well as during initial cardiac upstroke
Plug flow
Usually seen downstream once laminar flow is fully developed
Parabolic flow
Energy loss occurs at the
Exit of a stenosis
Inertial losses occur with deviations from laminar flow, due to
Direction and /or velocity changes
Stored energy is released when walls
Recoil
Kinetic energy (velocity)
Motion/forward
When standing ankle pressure equals
Circulatory pressure plus 100mmHg
The size of the vessel equals
Radius
Defines relationships between pressure, volume flow, resistance
Poiseuille’s equation
Helps define how much fluid volume moves through vessel
Poiseuille’s equation
Diminishing vessel size
Increases frictional forces and heat energy loss.
