Chapter 2 Physiology and Hemodynamics Flashcards
Pressure is greatest at what organ in the body
The heart
If the resistance is low what happens to the flow rate
It is higher
What governs the amount of blood that enters the arterial system
Cardiac output
If the resistance is higher what happens to the flow rate
It’s lower
What is another name for pressure energy
Potential
Pressure energy is expressed in what
mm Hg
______ energy is stored energy and is the major form of energy for circulation of blood
Pressure
______ energy is expressed in terms of fluid density and it’s velocity measurements
Kinetic
What’s another term used for gravitational energy
Hydrostatic pressure
_________ energy is equivalent to the weight of the column of blood extending from the heart to level where pressure is measured
Gravitational
What is needed to move blood from one point to another
Energy gradient
This is related to the tendency of a fluid to resist changes in its velocity
Inertia
Internal friction within a fluid is measured by its
Viscosity
Energy is lost in the form of
Heat
Elevated hematocrit does what to blood viscosity (thickness of a fluid)
A) increases
B) decreases
Increases
Severe anemia does what to blood viscosity
A) increases
B) decreases
B) decreases
How are viscosity and velocity related
A) directly
B) indirect
B) indirect
Diminishing vessel size _______ frictional forces and heat energy losses
A) increases
B) decreases
A) increases
What consists of layers of fluid particles moving against one another
Laminar flow
The fastest moving flow in located where
In the center
Laminar flow is considered
Stable flow
Plug flow is likely seen where
At the vessel origin
________ energy loss is due to increased friction between molecules and layers which ultimately cause energy loss
Viscous
________ losses occur with deviations from laminar flow due to changes in direction and or velocity
Inertial
Inertial loss occurs where in relation to a stenosis
At the exit
What type of parabolic flow profile becomes flattened and moves in a disorganized fashion
Inertial losses
What defines the relationship between pressure, volume flow and resistance
Poiseuille’s equation
What is the equation for Poiseuille
Q=P/R
What is the equation for electricity (Ohms Law)
I=V/R
The law of what explains the relationship between velocity and area
Law of Conservation of Mass
What is the equation for Law of Conservation of Mass
Q=A x V
The total energy contained in moving fluid is the sum of pressure, kinetic, and gravitational energies describes
Bernoulli Law
What is the relationship between velocity and pressure
Inversely related
________ __________ result in regions with stagnant or little movement
Flow separations
_______ flow originated from a steady driving pressure
Steady
_______ flow changed both the driving pressure conditions as well as the response of the system
Pulsatile
Forward flow throughout the periphery describes
A) systole
B) diastole
A) systole
Temporary flow reversal due to a phase shifted negative pressure gradient and peripheral resistance causing reflection of the wave proximally describes
Late systole/ early diastole
This is when flow is forward again as a reflective wave hits the proximal resistance of the next incoming wave and reverses
Late diastole
What type of flow is of a continuous (steady) nature feeding a dilated vascular bed
Low resistance
The ICA, vertebral, renal, celiac, splenic, and hepatic arteries are what type of flow
Low resistance. They are constantly demanding flow
What type of flow is of a pulsatile nature
High resistance
The ECA, subclavian, aorta, iliac, extremity arteries and fasting SMA are examples of what type of flow
High resistance
Doppler flow distal to a significant stenosis is _______ resistant
A) higher
B) lower
B) Lower
Doppler flow proximal to a significant stenosis is ______ resistant
A) higher
B) lower
A) higher
Pulsatile changes in medium and small sized arteries of the limbs are increased describes
A) Vasoconstriction
B) vasodilation
A) Vasoconstriction
Pulsatile changed in medium and small sized arteries of the limbs are decreased describes
A) Vasoconstriction
B) Vasodilation
B) vasodilation
Increased volume flow
Reversed flow direction
Increased velocity and
Waveform pulsatility changes describe what type of obstruction
Arterial
Collaterals are usually low resistive due to ______ disease
A) proximal
B) distal
A) proximal
________ is probably best single vasodilator of resistance vessels within skeletal muscle
Exercise
_________ is the ability of most vascular beds to maintain a constant level of blood flow over a wide range of perfusion pressures
Autoregulation
When BP rises what happens to the resistance of the vessels
A) constricts
B) dilated
A) constricts
When BP falls what happens to the resistance of the vessels
A) constricts
B) dilated
B) dilates
Peripheral dilatation occurs in response to ______ arterial obstruction
A) proximal
B) distal
A) proximal
A ________ significant stenosis causes a noteable reduction in volume flow and pressure
Hemodynamically
KNOW!
Cross sectional area reduction of _____% = a diameter reduction from of _____%
75, 50
______ to a stenosis flow frequencies are usually dampened with or without disturbance
A) proximal
B) distal
A) proximal
________ into the stenosis produces an increase in Doppler shift frequencies resulting in spectral broadening and elevated velocities
Entrance
_______ ________ occur due to interrupted flow stability with high velocity use and eddy currents
Flow disturbance
At stenosis _______ flow reversals, flow separations, vortices/eddy currents occur near edge of flow pattern
Exit
Flow quality is comprised of multiple changes in direction and spectral broadening as displayed by the spectral pattern describes what type of turbulence
Post stenotic
Approximately how many ml of blood is pumped into the aorta
70 ML
What is amount of blood ejected called
Stroke volume
What is the main form of energy present in flowing blood
Pressure energy
_______ energy is created by the pumping action of the heart
Pressure
_______ energy is the ability of flowing blood to do work as a result of its velocity
Kinetic
Kinetic energy is proportional to the ______ of _______
Density of blood
The right atrium is considered the _____ pressure reference point
0
The greatest amount of energy is produced at _____ systole
Peak
During the deceleration phase of the pulse cardiac output ______
Decreases
What type of flow does blood move in concentric layers or laminae
Laminar
During laminar flow it’s velocity is slowest at the ______ ______
Vessel wall
During laminar flow it’s velocity is fastest at the ______ of the vessel
Center
What are the 2 forms of laminar flow
1) parabolic flow
2) plug flow
What type of flow has a profile that resembles the shape of a bullet
Parabolic
During parabolic flow velocity is highest in the ______ of the lumen gradually decreasing at the vessel wall
Center
________ flow occurs when all the blood cells and layers travel at the same velocity
Plug
What is the relationship between viscosity and velocity
Inverse
Increased viscosity = _______ velocity
Decreased
Low viscosity = _____ hematocrit and severe _______
Low hematocrit and severe anemia
What is the relationship between the radius of a vessel and volume flow
Directly proportional
What is the relationship between vessel radius and resistance
Inverse
What are 2 other names for small circular currents
1) eddy currents
2) vortices
When the Reynolds number exceeds ______ laminar flow tends to become disturbed
20000
Vessel wall vibration due to turbulent flow may cause ______
Bruits
In the region proximal to a stenosis the pressure energy is ______ and the kinetic energy is_______
Higher
Lower
Distal to a stenosis the kinetic energy ________ and the pressure energy _______
Decreases
Increases
_________ ___________ are the difference be pressure between 2 points in a vessel
Pressure gradients
During ______ there is no movement of blood and therefore no color in the color flow image
Diastole
_______ flow is the result of a steady driving pressure that initiates movement of a viscous fluid through a conduit
Steady
Non steady conditions include what 3 things
1) acceleration
2) deceleration
3) rest
Flow reversal decreases or is absent with _________
Vasodilation
Vasodilation can be produced by what 3 things
1) body heating
2) exercise
3) stenosis
Flow reversal increases with _______
Vasoconstriction
