Deck 14: Overview of the Circulation; Biophysics of Pressure, Flow, and Resistance

Question 1

If the blood flow through the kidney is 1200 mL/min and the renal artery pressure is 100 mm Hg and the renal venous pressure is 0 mm Hg, which of the following is the conductance (in mL/min/mm Hg) of the renal vessel?

A)2
B)4
C)8
D)12
E)16

Answer 1

D

Question 2

An increase in shear stress in a blood vessel would result in which of the following changes?

A)Decreased endothelin production
B)Decreased cyclic guanosine monophosphate production
C)Increased nitric oxide release
D)Increased renin production
E)Decreased prostacyclin production

Answer 2

C

Question 3

An increase in which of the following would decrease blood flow across a vessel?

A)Hydrostatic pressure gradient
B)Diameter of vessel
C)Blood viscosity
D)Plasma colloid osmotic pressure

Answer 3

C

Question 4

Which of the following components of the circulation has the lowest velocity of blood flow?

A)Arteries
B)Venules
C)Veins
D)Aorta
E)Capillaries

Question 5

The diameter of a precapillary arteriole is increased in a muscle vascular bed. A decrease in which of the following would be expected?

A)Capillary filtration rate
B)Vascular conductance
C)Capillary blood flow
D)Capillary hydrostatic pressure
E)Arteriole resistance

Question 6

A 78-year-old woman has a mean arterial pressure of 120 mm Hg and a heart rate of 60 beats/min. She has a stroke volume of 50 mL, cardiac output of 3000 mL/min, and a right atrial pressure of 0 mm Hg. What is the total peripheral resistance (in mm Hg/mL/min) in this woman?

A)0.01
B)0.02
C)0.04
D)0.08
E)0.10

Question 7

Which vessel has the highest vascular resistance? $$\begin{array} { l l l } \underline{\text { Vessel }} &\underline{ \text { Blood Flow } ( \mathrm { mL } / \mathrm { min } )} & \underline{\text { Pressure Gradient } ( \mathrm { mmHg } )} \\\text { A } & 1000 & 100 \\\text { B } & 1200 & 60 \\\text { C } & 1400 & 20 \\\text { D } & 1600 & 80 \\\text { E } & 1800 & 40\end{array}$$

Question 8

The arterioles are constricted in a muscle bed of an experimental animal. Which set of physiological changes would be expected to occur in response to constriction of the muscle arterioles?

Question 9

The table below depicts the pressure gradient, radius, and viscosity in various vessels of the same length. Which vessel has the greatest flow? $\begin{array}{llcc}\underline{\text { Vessel }} & \underline{\text { Pressure Gradient }} &\underline{ \text { Radius }} &\underline{ \text { Viscosity} }\\\text {A}&100&1&10\\\text {B}&50&2&5\\\text {C}&25&4&2\\\text {D}&10&6&1\end{array}$

Question 10

A 50-year-old woman has a renal blood flow of 1000 mL/min and hematocrit of 50%. Her arterial pressure is 120 mm Hg and her renal venous pressure is 20 mm Hg. She also has a plasma colloid osmotic pressure of 25 mmHg. What is the total renal vascular resistance (in mm Hg/mL/min) in this woman?

A)0.10
B)0.20
C)0.50
D)1.00
E)1.50

Question 11

Which of the following would tend to cause an increase in blood flow?

A)Increase in hematocrit
B)Decrease in arterial pressure
C)Twofold increase in arteriole diameter
D)Twofold increase in blood viscosity

Question 12

Under controlled conditions, flow through a blood vessel is 10 mL/min under a pressure gradient of 100 mm Hg. An increase in which of the following would occur in response to a twofold increase in the diameter of the vessel with a pressure gradient maintained at 100 mm Hg?

A)Vascular resistance
B)Hematocrit
C)Vascular conductance
D)Blood viscosity
E)Plasma oncotic pressure