Vascular final review Flashcards
(Vessel wall)
Tunica externa
AKA, Tunica adventitia. the outer layer made of connective tissue.
(Vessel wall)
Tunica media
Middle layer. This layer is thicker and more contractile in arteries than in veins.
(Vessel wall)
Tunica intima
The inner lining of the arterial wall, thinnest layer, comprised of a single layer of endothelium supported by a subendothelial layer.
What is the primary function of the Vasa Vasorum
To provide nourishment to the tunica adventitia. Larger arteries and veins that contain small blood vessels within their walls
The ability of a vessel to store potential energy.
How much it expands (compliance). its ability to recoil (capacitance)
Which is naturally more compliant. Veins or arteries
Veins are naturally more compliant than arteries (they expand more)
*Arteries exhibit more capacitance than veins (they recoil more)
Vasodilation
increase in blood flow in response to demand
Vasoconstriction
decrease in blood flow in response to lower blood pressure
Vessels that regulate blood flow, also called resistance vessels
Arterioles
(Hemodynamics)
Laminar Flow
Layered manner in which blood flow courses within an arterial. Seen in most arteries
(Hemodynamics)
Turbulent flow
Turbulent flow occurs both in normal and abnormal conditions. Blood flow is disrupted and no longer flows in smooth layers and is instead considered chaotic and unorganized
Pressure gradients
increase when flow
increases or resistance
increases. T/F
(True)
ENERGY IS
LOST THROUGHOUT THE BODY DURING
EACH CARDIAC
CYCLE. T/F
(True)
Measure of the resistance of blood to flow. Described as the thickness and stickiness of blood
Blood Viscosity
Relationship between Diameter and Velocity
As the diameter decreases the velocity increase. As the diameter increases the velocity decrease
What describes the relationship between volume flow (Q), pressure (P), and
resistance (R).
Poiseuille’s Law
The pressure at a stenosis is less than the pressure proximal and distal to the stenotic area.
Bernoulli Principle
The amount of fluid moving past a point at a specific time is known as
volumetric flow rate
Compared to the arteries, veins have?
More collagen and elastic fibers than muscle fibers
What factor has the greatest influence on flow resistance?
Vessel radius
On which axis on the spectral display is time displayed?
x-axis
(Viscosity)
If resistance increases, what happens to flow?
decreases
The movement of blood flow is what type of energy?
Kinetic Energy
Helical flow (eddy currents) with flow separation on the wall away from the flow divider is a sign of?
Normal flow dynamics
The physical principles associated with the study of blood circulation are termed:
hemodynamics
Peripheral resistance (downstream at the arterial bed) is controlled by?
Vasoconstriction and vasodilation of the arterioles
The Reynolds number describes the?
Point at which resistance to flow becomes turbulent
If the viscosity of blood increases, what happens to resistance?
increases
The ability of veins to accommodate large shifts in volume with only limited changes in venous pressure is known as?
Compliance
Flow characterized by multiple velocity and direction components is called:
turbulent flow
What does the number 2000 represent in the formula for Reynolds number?
Turbulent flow
The smallest vessels in the body are?
Capillaries
According to Poiseuille’s law, what would occur to the pressure gradient across an arterial segment in which the radius has been reduced by one-half?
It would increase
Constant flow velocity across the vessel is termed:
Laminar Flow
During systole, a nonrigid arterial wall will expand and in diastole it recoils. This is known as:
Capacitance
The energy of something in motion is termed?
Kinetic Energy
Within the circulatory system, pressure differences and flow rate are:
directly related
What must be present in order for flow to occur?
pressure gradient
What is the Doppler effect?
A change in the frequency in the detected wave when the source or the detector is
moving
What is the difference between the gradient during systole and
diastole?
During systole the gradient is larger
During diastole, the gradient is smaller
What does the abbreviation ALARA stand for?
As low as reasonable achievable
Which setting produces the most heat out of M mode, color Doppler and pulsed
wave Doppler
Pulsed wave doppler
What must sound travel through
Medium
What does sound NOT travel through?
Vaccum
Absorption increases with
Frequency
How much energy of the sound wave is lost due to the absorption
80%
What happens to the pressure level during a stenosis
Decreases
The difference between the pressure within the vein (intramural) and the tissue pressure outside the vein (interstitial)
Transmural Pressure
Which of the following causes the veins to lose their elliptical shape and become more circular?
increased transmural pressure
With laminar flow in a straight vessel, what part of the flow is said to be fastest?
In the center of the stream
A 50 % reduction in diameter is equal to what percent reduction in area?
75%
The difference in pressure within the vein and the tissue pressure outside the vein is due to?
Transmural pressure
The total energy of the vascular system has two primary components, which are
Potential and kinetic energy
Anterior is defined as
Toward the front
The term “muscle pump” refers to
The calf muscles
According to the Bernoulli principle, if the velocity of blood goes up, what must happen?
There must be a pressure decrease
Peripheral resistance is controlled by:
vasoconstriction and vasodilatation of the arterioles
Blood within the pulmonary veins
Contains high oxygen content and flows into the left atrium
Which of the following is the body plane that separates the body into superior and inferior sections?
Transverse
What is the effect of inspiration on venous flow in the lower extremities?
Venous flow in the lower extremities stops during inspiration and returns during expiration.
In the vascular system, which are the main two factors that result in “energy losses”
Friction and Viscosity
Intra-abdominal pressure is decreased with:
expiration
A doubling in the length of a stenosis results in:
A 2-fold increase in energy losses across the stenosis
At any moment, how much of the body’s blood volume is found in the veins?
60%–75%
Anechoic describes a region which
Does not return any echoes
The type of pressure that is greatly influenced by gravity is
hydrostatic pressure
The greatest inertial energy losses occur
….as blood exits a stenosis
A venule contains which vessel layers?
Tunica adventitia, tunica media and tunica intima
Which term is not a component within the definition of Poiseuille law?
Inertia
Nutrient and waste exchange occur in which blood vessel?
Capillaries
Which plane splits the body into anterior and posterior sections?
Coronal
Venous pressure and flow are affected by
Velocity of the blood
The abbreviation PSV stands for:
Peak systolic velocity
A critical stenosis is where
Both pressure and flow decrease
The gravitational weight of a column of blood that extends from the heart to a level where blood pressure is determined is
hydrostatic pressure
Which position would result in the greatest hydrostatic pressure?
Standing
`Why would an incorrect placement of a sample volume cause a difference in measured velocity?
A parabolic blood flow profile means that the blood flow at the edges of the vessel lumen will be slower than the layers towards the middle due to friction
A noise that is produced by the vibrations of the surrounding tissues as the result of turbulence in the artery that is commonly heard with a hemodynamically significant stenosis is known as
A bruit
What percentage of blood flow does the ICA (internal carotid artery supply to the brain?
70% TO 80%
The intimal media thickness (IMT) should be reported when it is?
abnormally thick > 1mm
Which ICA distortion is most often associated with symptoms of cerebral ischemia?
Kinking
What is the maximum recommended Thermal index in soft tissue (TIS) that is in keeping with ALARA principles
1.0
The innominate artery gives rise to which two arteries?
Right common carotid and right subclavian arteries
Low diastolic flow in a vessel results in?
High resistive index
The arteries that originate from the proximal subclavian arteries and course along the posterior aspect of both sides of the neck are the
Vertebral arteries
A tiny ovoid structure 1 to 1.5 mm in size located in the adventitia of the carotid bifurcation is?
Carotid Body
Greater than 50% of bifurcations of the carotid artery are higher on?
Left side
Which vessel normally supplies NO blood to the brain?
ECA
What is the most common area for atherosclerotic disease in the extracranial arteries?
Proximal internal carotid
The vertebral arteries join to form which vessel intracranially?
Basilar artery
What type of waveform would you most likely expect to see distal to a 80% to 99% stenosis?
Tardus-parvus waveform
If the carotid artery blood flow is expected to be 70 - 80 cm/s the velocity range covered by the color map should be set at?
30 - 40 cm/s
The first branch off the external carotid artery is
Superior thyroid artery
The first branch off the internal carotid artery is the
Ophthalmic artery
A patient having a carotid duplex examination has the following velocities obtained. What is your diagnosis?
Greater than 70% stenosis
What maneuver produces fluctuations in the spectral waveform of the external carotid artery?
Temporal artery tap
A 50 % reduction in diameter is equal to what percent reduction in area?
75%
Collateral flow has a better chance of developing adequately in persons with?
slowly evolving atherosclerotic occulsions
The most common variant of the Aortic Arch is?
Bovine arch/common origin
Homogenous plaque can be described as
Uniform echo pattern
The index most often used during pregnancy to determine high risk is?
Systolic/Diastolic (S/D) ratio
Which of the following becomes an extracranial to intracranial collateral route in the presence of significant ICA disease
Ophthalmic arteries via ECA branches
A bright yellow spot noted within a branch artery upon ophthalmologic examination is called?
Hollenhorst plaque
The maximal post-stenotic flow disturbance (turbulence) occurs?
within 1 cm past the stenosis
