Vascular Physiology

Question 0

Elderly patients typically have____ arterial wall compliance resulting in____.

Answer 0

Decreased, increased systolic pressure

Question 1

The elastic arteries filter and smooth out the pulsatilla pressure within the aorta. This effect is termed

Answer 1

Windkessel effect

Question 2

The definition of vascular compliance is

D = change in

Answer 2

D volume/ D pressure

Question 3

The aorta stores blood during systole and releases it during diastole. This physical compliance is analogous to electrical

Answer 3

Capacitance

Question 4

Systolic arterial blood pressure is inversely proportional to

Answer 4

Arterial compliance

Question 5

Venous capacitance (compliance) is normally ____ times greater than arterial capacitance.

Answer 5

20

Question 6

The normal static circulatory pressure at zero cardiac output is approximately

Answer 6

7 to 13mmHg

Question 7

In a large vessel with fully developed laminar flow the velocity of the central stream is

Answer 7

Twice the mean velocity

Question 8

The velocity of blood touching any arterial wall always equals

Answer 8

Zero

Question 9

Blood flow will change from laminar to turbulent at a Reynolds number

Answer 9

Over 2000-3000

Question 10

The cerebral circulation is a

Answer 10

High-flow, low resistance system

Question 11

How is cerebral blood flow effected by changes in blood pressure?

Answer 11

Cerebral perfusion decreases in hypotension. (Mean BP less 75)

Question 12

What happens to the metabolic rate of the brain with sleep?

Answer 12

Brain metabolic rate is unchanged, compared to waking

Question 13

What mechanism is primarily responsible for returning venous blood to the heart while walking?

Answer 13

Skeletal muscle

Question 14

When a Doppler probe is directed at an arterial stenosis the operator hears a high pitched rushing sound because of

Answer 14

Increase of velocity of blood flow at the lesion.

Question 15

What is the peripheral or systemic vascular resistance formula?

Answer 15

SVR = (mean AO-mean RA)/ CO

Question 16

Blood behaves as a ____ fluid in very small vessels.

Answer 16

Non-Newtonian

Question 17

Poiseuille’s law is not applicable in capillaries because the apparent viscosity of blood decreases as blood flow rate and vessel diameter decrease. This is termed

Answer 17

Shear thinning

Question 18

Which fluid has the highest viscosity?

Answer 18

Polycythemic blood

Question 19

In the Bernoulli equation, what is the relationship between the kinetic and potential energy?

Answer 19

Their sum is constant.

1/2mv squared + mgh

Question 20

Bernoulli law law explains why in aortic stenosis the aortic blood flow velocity is ____ and the aortic pressure is _____.

Answer 20

Increased, decreased

Question 21

Normally the pulmonary and systemic blood flow circuits are arranged _____ to/with each other. (Unless there is a shunt)

Answer 21

In series

Question 22

Two arteries in the kidneys in series are the peritubular and glomerular arteries. They have resistance of 80 units each. If the mean arterial BP is 100 and CVP=0, calculate flow through the kidney.

Answer 22

625 cc/min

Question 23

Calculate the equivalent resistance of 2 blood vessels in parallel. Each is 50 resistance units(Ohms) as shown.

Answer 23

25 units

Question 24

Calculate the equivalent total resistance of the arteries shown if the combined flow = 3L/min and the pressure drop = 80 mmHg.

Answer 24

26.6 Wood or HRU units

Question 25

The hemodynamic effect of increasing a patient's peripheral vascular resistance is to: (assume constant CO)

Answer 25

Increased BP

Question 26

At peak exercise a normal individual's mean blood pressure may not significantly elevate, even though CO may increase up to 7 times. This regulation of BP on exercise is due to _____ vascular resistance.

Answer 26

Decreased systemic

Question 27

Who developed the law: T=PxR/(2x wall thickness)? T= wall tension P=pressure R=radius

Answer 27

La Place

Question 28

Thin-walled capillaries can withstand high internal pressure without bursting because of their narrow lumen. Who's law?

Answer 28

La Place's

Question 29

The law of La Place explains why small blood vessels may collapse during circulatory shock. This is because tension within the small vessel wall

Answer 29

Increases above what the reduced BP can overcome

Question 30

Leg stockings will increase which variable of the starling fluid movement hypothesis?

Answer 30

Pi interstitial fluid hydrostatic pressure

Question 31

What pathologic condition is likely to occur when the pulmonary capillary pressure is greater than plasma oncotic pressure?

Answer 31

Pulmonary edema

Question 32

The key factor restraining fluid loss from a systemic capillary is

Answer 32

Osmotic pressure due to plasma proteins

Question 33

If arterial blood flow is stopped for several minutes by pumping up a BP cuff around a limb and then releasing it, the resulting flow exceeds basil flow. This is termed

Answer 33

Reactive hyperemia

Question 34

Dilation of arteries may occur due to increased flow through to them. This occurs after liberation of "endothelial derived relaxation factor" that is composed of

Answer 34

Nitric oxide

Question 35

Brief exposure of an extremity to extreme cold temperatures results in _____ the vessels in that extremity.

Answer 35

Neural mediated vasoconstriction

Question 36

Soldiers standing at attention for long periods often faint because

Answer 36

Venous pooling reduces preload and cardiac output

Question 37

An embolus can be best described as any: (remember even air can embolize)

Answer 37

Foreign material that travels downstream and plugs up a vessel

Question 38

Elevated blood Angiotensin II and aldosterone levels cause

Answer 38

Arteriolar vasoconstriction

Question 39

Angiotensin II liberates aldosterone, which is a ____ causing the kidneys to____ Na.

Answer 39

Corticosteroid, retain

Question 40

The chief regulation of blood flow within the lung away from atelectatic areas is local vasoconstriction due to ______ in that atelectatic area.

Answer 40

Decreased PO2 tension

Question 41

Active transport of substances across endothelial walls, especially large lipoproteins, is termed

Answer 41

Pinocytosis