Arterial Physiology and Hemodynamics

Question 1

Cardiac contraction begins:

Answer 1

Pressure in the left ventricle rises rapidly.
Left ventricle pressure exceeds that in the aorta.
aortic valve opens, blood is ejected, BP rises

Question 2

The heart pump:

Answer 2

Generates the pressure to move the blood.
Results in a pressure wave that travels rapidly throughout the system, demonstrating a gradual transformation as it travels distally.

Question 3

Each beat pumps about how many milliliters of blood into the aorta causing a blood pressure pulse?

Answer 3

70

Question 4

What governs the amount of blood that enters the arterial system?

Answer 4

Cardiac output

Question 5

What determines the amount of blood that leaves the arterial system?

Answer 5

arterial pressure and total peripheral resistance

Question 6

movement of any fluid medium between two points requires what two things?

Answer 6

A pathway along which the fluid can flow.

Difference in energy levels (pressure difference)

Question 7

The amount of flow depends upon what?

Answer 7

Energy difference.

Any resistance which tends to oppose such movement.

Question 8

Flow depends upon resistance and flow rate:
lower resistance=
higher resistance=

Answer 8

higher flow rate

lower flow rate

Question 9

Total energy contained in moving fluid is the sum of what energies?

Answer 9

pressure, kinetic, and gravitational

Question 10

What is the major form of energy for circulating blood?

Answer 10

pressure energy (mmHg)

Question 11

What energy is small for circulating blood? Expressed in terms of fluid density and its velocity measurements.

Answer 11

kinetic energy

Question 12

What is equivalent to the weight of the column of blood extending from the heart to level where pressure is measured?

Answer 12

gravitational energy or hydrostatic pressure

Question 13

When supine there is 0 mmHg against the arterires and veins at the ankle. When standing the HP increases to what?

Answer 13

100 mmHg

Question 14

An energy gradient is needed for what?

Answer 14

moving blood from one point to another. greater the gradient, the greater the flow.

Question 15

R= 8nL/πr^4

Answer 15

R= resistance
n= viscosity
r= radius
L= vessel length
R is directly proportional to variables in numerator and indirectly to the variable in the denominator.

Question 16

What has a more dramatic effect on resistance than viscosity and vessel length?

Answer 16

vessel diameter

Question 17

factors affecting resistance to flow?

Answer 17

physical properties of the fluid and what its moving through

Question 18

viscosity ans velocity
greater viscosity=
less viscosity=

Answer 18

less velocity

greater velocity

Question 19

viscous energy loss is due to what?

Answer 19

increased friction between molecules and layers

Question 20

Inertial losses occur with deviations from laminar flow due to what?

Answer 20

Changes in direction and/or velocity. occurs at the exit of a stenosis

Question 21

Poiseuilles equation helps answer the question of how much fluid moves through vessel and defines the relationship between what?

Answer 21

Pressure, volume flow, and resistance

Q=P/R

Question 22

area and velocity
greater area=
less area=

Answer 22

less velocity

greater velocity

Question 23

pressure/velocity relationships

Answer 23

sum of pressure, kinetic, and gravitational energies. If one changes the others make up for the difference in order to maintain the original total fluid energy.

Question 24

velocity and pressure
greater velocity=
less velocity=

Answer 24

less pressure

greater pressure

Question 25

Systole: Late systole/early diastole: Late diastole:

Answer 25

Forward flow Temporary flow reversal Forward flow again

Question 26

low resistance flow consists with what? continuous

Answer 26

ICA, vertebral, renal, celiac, splenic, hepatic

Question 27

high resistance flow occurs in what? pulsatile

Answer 27

ECA, subclavian, aorta, iliac, extremity arteries, fasting SMA

Question 28

Doppler flow distal to a significant stenosis is?

Answer 28

lower resistance, more rounded, and weaker in strength

Question 29

Doppler flow prox to stenosis is what?

Answer 29

Higher resistance | A normally high resistant signal may become monophasic closer to stenosis.

Question 30

Pulsatile changes in medium/small sized arteries of the limbs are increased. Pulsatility changes usually decreased in the minute arteries.

Answer 30

vasoconstriction

Question 31

decreased pulsatile changes in medium/small arteries of the limbs. Pulsatility changes are increased in minute arteries.

Answer 31

vasodilatation

Question 32

As the inflow pressure falls as a result of stenosis, the natural responsein periphery is to what?

Answer 32

Vasodialte to maintain flow

Question 33

collateral effects

Answer 33

``` Increased flow volume Reversed flow direction Increased velocity Waveform pulsatility changes Location of collaterals helps provide tentative area of obstruction ```

Question 34

Exercise should induce peripheral ______ which lowers distal peripheral ______, increasing blood flow.

Answer 34

vasodilatation, resistance

Question 35

What is the best single vasodilator of resistance vessels within skeletal muscles?

Answer 35

exercise

Question 36

What is the ability of most vascular beds to maintain constant level of blood flow over a wide range of perfusion pressures.

Answer 36

Autoregulation

Question 37

BP rise: | BP fall:

Answer 37

Constriction of resistance vessels. | Dilatation of resistance vessels.

Question 38

vasodilatation vasoconstriction what type of signals?

Answer 38

continuous, lower | pulsatile, higher

Question 39

Entrance into stenosis increase in doppler shift frequencies resulting in what?

Answer 39

spectral broading and elevated velocities

Question 40

post-stenotic turbulence

Answer 40

Flow quality is comprised of multiple changes in direction and spectral broadening as displayed by the spectral pattern. Energy expended as heat.