Question 1

Your Professor’s stroke volum e at rest is 90 mL (because he has a big heart - believe it or not). His systolic pressure is 135 m m Hg and diastolic is 90 mm Hg. W hen reading your exam s, his systolic pressure climbs to 150 mm Hg while diastolic pressure is unchanged. Assume no change
in compliance of his arteries. Your Professor’s stroke volume while reading your exams

Accepted Answer

B

Question 2

If the flow through an artery obeys Poiseuille’s law, decreasing the radius of an artery by a factor of 2 should

Accepted Answer

Poiseuille’s law indicates that resistance is inversely proportional to the fourth power of the radius of the artery. Therefore, if the radius is decreased by a factor of 2, the resistance increases by a factor of $2^4 = 16$.

Question 3

The ratio of venous to arterial compliance is about

Accepted Answer

Venous compliance is significantly higher than arterial compliance, with the venous system being about 20 times more compliant than the arterial system.

Question 4

The compliance of the aorta and major arteries

Accepted Answer

The compliance of the aorta and major arteries, along with the stroke volume, determines the pulse pressure by affecting how much the arteries can expand and contract with each heartbeat.

Question 5

W hich of the following is NOT one of the functions of the vasculature?

Accepted Answer

The primary functions of the vasculature include acting as a volume reservoir, facilitating the exchange of materials in the tissues, distributing flow to the organs, and containing the blood. Fighting off viral and bacterial infections is not a direct function of the vasculature; this role is primarily performed by the immune system.

Question 6

Blood pressure is measured clinical by a device called

Accepted Answer

A sphygmomanometer is the correct device used for measuring blood pressure clinically. It typically consists of an inflatable cuff to restrict blood flow, and a mercury or aneroid manometer to measure the pressure.

Question 7

Com pliance is DEFINED as

Accepted Answer

Compliance is defined as the change in volume ($\Delta V$) per unit change in pressure ($\Delta P$), which is accurately represented by option A: C = $\Delta V / \Delta P$.

Question 8

The dicrotic notch is caused by

Accepted Answer

The dicrotic notch on the arterial pulse waveform is caused by the closure of the aortic valve, which momentarily interrupts the smooth decline of the pressure curve following systole.

Question 9

The difference in time between ejection of blood and the first Korotkoff sound in the brachial artery at the antecubital fossa is about (choose the best answer - obviously none are right on the money)

Accepted Answer

The first Korotkoff sound, which is heard when taking blood pressure with a sphygmomanometer, occurs due to the turbulent flow of blood as it starts to pass through the partially compressed artery. This sound is heard shortly after blood is ejected from the heart, and the most accurate approximation among the given options is 0.1 seconds (C), as the delay accounts for the time it takes for the pressure wave to travel from the heart to the point of measurement and for the blood flow to become turbulent enough to produce an audible sound.

Question 10

The difference between lateral and end pressure is

Accepted Answer

The difference between lateral and end pressure is due to the conversion of kinetic energy into pressure energy, which is related to the equivalent pressure of the kinetic energy of the blood.

Question 11

During a routine blood pressure measurem ent, the external pressure imposed on the radial artery is just a little lower than the systolic pressure. Blood squirts through the artery and produces a noise called the

Accepted Answer

The first Korotkoff sound is the noise heard through a stethoscope applied to the arm when the cuff pressure is just below the systolic blood pressure, indicating the resumption of blood flow into the forearm.

Question 12

The muffling or disappearance of the Korotkoff sound occurs at a pressure corresponding to the

Accepted Answer

The muffling or disappearance of the Korotkoff sound occurs at a pressure corresponding to the diastolic pressure, which is when the artery is no longer compressed and blood flow is unrestricted and silent.

Question 13

Flow velocity in the vasculature is greatest in the

Accepted Answer

Flow velocity is greatest in large arteries primarily because the total cross-sectional area is least in these vessels, allowing for faster blood flow compared to areas where the cross-sectional area is larger.

Question 14

The velocity of the pressure pulse in a normal adult is about

Accepted Answer

The velocity of the pressure pulse in a normal adult is approximately 5 meters per second.

Question 15

The largest pressure drop in the circulation occurs in the

Accepted Answer

The largest pressure drop in the circulation occurs in the arterioles. This is because arterioles are the primary site of vascular resistance, controlling blood flow through the regulation of their diameter.

Question 16

Which of the following is NOT one of the assumptions for Poiseuille flow?

Accepted Answer

Poiseuille flow assumes laminar flow, not turbulent flow. The other options (B, C, D, E) are consistent with the assumptions for Poiseuille flow.

Quiz 40: Vascular Function: Hemodynamics