Question 1

The mean systemic pressure is
A) The average of the central venous pressure and m ean arterial pressure
B) Measured w ith the heart stopped and blood redistributed so that flow is zero
C) Measured in the right atria during diastole
D) Measured in the central veins during systole
E) The average pressure in the central veins

Accepted Answer

Mean systemic pressure is measured with the heart stopped and blood redistributed so that flow is zero, reflecting the average pressure in the systemic circulation independent of the pumping action of the heart.

Question 2

W hich is NOT part of the sympathetic effects on cardiovascular system?
A) Increased heart rate
B) Vasoconstriction
C) Increased cardiac contractility
D) Increased filtration coefficient across capillary walls
E) Venoconstricti

Accepted Answer

The sympathetic nervous system primarily increases heart rate, vasoconstriction, cardiac contractility, and venoconstriction to enhance blood flow to muscles and vital organs during stress or physical activity. It does not directly increase the filtration coefficient across capillary walls; this parameter is more influenced by factors like capillary permeability and hydrostatic and oncotic pressures.

Question 3

At steady-state, the flow through the pulmonary circulation
A) Is the same as the cardiac output
B) Exceeds the cardiac output by the flow to the liver
C) Exceeds the cardiac output by the flow to the lung
D) Is the cardiac output minus the flow to the liver
E) Is the cardiac output minus the flow to the lung

Accepted Answer

At steady-state, the flow through the pulmonary circulation is the same as the cardiac output because all the blood pumped by the right ventricle into the pulmonary circulation returns to the left atrium and is then pumped by the left ventricle into the systemic circulation. There is no subtraction or addition of flow in the pulmonary circulation compared to the cardiac output.

Question 4

Most of the total peripheral resistance (TPR) is in the
A) Major arteries
B) Sm all arteries
C) Arterioles
D) Capillaries
E) Veins

Accepted Answer

Arterioles are the primary site of vascular resistance in the circulatory system, significantly contributing to the regulation of blood pressure and the distribution of blood flow.

Question 5

The compliance of the veins is much greater than the compliance of the arteries because
A) Veins have ellipsoidal cross sections and not circular cross sections
B) Veins are larger
C) Arteries are stiffer
D) Arteries have more parasympathetic innervation
E) The pressure is lower on the venous side

Accepted Answer

Arteries are stiffer than veins, which allows veins to be more compliant. Compliance refers to the ability to expand and contract with changes in pressure, and the stiffer nature of arteries makes them less able to do this compared to the more flexible veins.

Question 6

The vascular function curve is traditionally plotted as flow on the ordinate against the right atrial pressure on the abscissa. In this case, venoconstriction
A) Decreases the X-intercept
B) Increases the X-intercept
C) Decreases the slope
D) Increases the slope
E) Both A and C are true

Accepted Answer

Venoconstriction increases venous return, which shifts the vascular function curve to the right, increasing the X-intercept (right atrial pressure at zero flow).

Question 7

The vascular function curve is traditionally plotted as flow on the ordinate against the right atrial pressure on the abscissa. In this case, decreasing the TPR
A) Decreases the X-intercept
B) Increases the X-intercept
C) Decreases the slope
D) Increases the slope
E) Both A and C are true

Accepted Answer

Decreasing the total peripheral resistance (TPR) increases the slope of the vascular function curve, as it allows for greater blood flow at any given right atrial pressure.

Question 8

At steady-state, the cardiac output
A) Is equal to TPR / MAP
B) Is equal to the flow in the abdominal aorta
C) Is equal to venous return
D) Determ ines the pulse pressure
E) Determ ines the pulse velocity

Accepted Answer

At steady-state, the cardiac output is equal to venous return, as the amount of blood being pumped by the heart per unit time must match the amount of blood returning to the heart.

Question 9

The plate au a t the hig h flow end of the vas cula r fun ction c urve is due to
A) Limited flow because of the reduced pressure gradient
B) High flow due to Increase d arterial pressure
C) Limit to flow caused by partial collapse or flutter of the veins
D) Failure of the muscle pumps to keep up
E) Low pressure caused by venodilation

Accepted Answer

The plateau at the high flow end of the vascular function curve is due to a limit to flow caused by partial collapse or flutter of the veins, which occurs when the venous return is high and the veins cannot accommodate the increased flow.

Question 10

The vascular function curve is traditionally plotted as flow on the ordinate against the right atrial pressure on the abscissa. In this case, the X-intercept is A) W here the veins collapse or flutter B) Equal to C_V / C_A C) 1 / TPR D) - (1 + C_V/ C_A) / TPR E) The mean system ic pressure

Accepted Answer

The X-intercept on a vascular function curve, plotted with flow on the ordinate and right atrial pressure on the abscissa, represents the mean systemic pressure. This is the pressure at which flow stops, indicating the pressure in the system without any flow.

Question 11

Sympathetic stim ulation should have which of the following effects A) Increase in P_MSbecause of vasoconstriction B) Increase in P_MS because of venoconstriction C) Increase in P _MSbecause of increased cardiac contractility D) Decrease in P_MS because of increased TPR E) Decrease in P_MS because of decreased slope of the vascular function curve

Accepted Answer

Sympathetic stimulation causes venoconstriction, which increases mean systemic filling pressure (P_MS) by mobilizing blood from the venous reservoir.

Question 12

In persons with a hypofunctional heart (weak contractility), the cardiac output is partially
compensated for by
A) An increase in the right atrial pressure
B) An increase in arterial pressure
C) Increased cardiac contractility
D) Vasodilation driven by sympathetic stimulation
E) Decreased interstitial fluid pressure

Accepted Answer

In persons with a hypofunctional heart, an increase in right atrial pressure can help compensate for decreased cardiac output by increasing venous return and preload, which can enhance stroke volume according to the Frank-Starling mechanism.

Question 13

The vascular function curve is traditionally plotted as flow on the ordinate against the right atrial pressure on the abscissa. In this case, the slope of the linear portion of the curve is A) - 1 + C_v/ C_A V / CA B) C_V/ C_A C) 1 / TPR D) - (1 + C_V/ C_A) / TPR E) 1/(C_V + C^A

Accepted Answer

The slope of the vascular function curve is determined by the total peripheral resistance (TPR) and the compliance of the venous (C_V) and arterial (C_A) systems. The correct expression for the slope is - (1 + C_V/ C_A) / TPR.

Question 14

The vascular function curve is traditionally plotted as flow on the ordinate against the right atrial pressure on the abscissa. In this case, the slope of the linear portion of the curve
A) Increases with increases in TPR
B) Increases with decreases in TPR
C) Increases its X-intercept with increases in TPR
D) Decreases its X-intercept with increases in TPR
E) Both A and C are true

Accepted Answer

The slope of the vascular function curve increases with decreases in total peripheral resistance (TPR), as lower TPR allows for greater venous return and cardiac output at a given right atrial pressure.

Quiz 43: Integration of Cardiac Output and Venous Return

The mean systemic pressure is

W hich is NOT part of the sympathetic effects on cardiovascular system?

At steady-state, the flow through the pulmonary circulation

Most of the total peripheral resistance (TPR) is in the

The compliance of the veins is much greater than the compliance of the arteries because

The vascular function curve is traditionally plotted as flow on the ordinate against the right atrial pressure on the abscissa. In this case, venoconstriction

The vascular function curve is traditionally plotted as flow on the ordinate against the right atrial pressure on the abscissa. In this case, decreasing the TPR

At steady-state, the cardiac output

The plate au a t the hig h flow end of the vas cula r fun ction c urve is due to

The vascular function curve is traditionally plotted as flow on the ordinate against the right atrial pressure on the abscissa. In this case, the X-intercept is

Sympathetic stim ulation should have which of the following effects

In persons with a hypofunctional heart (weak contractility) , the cardiac output is partially compensated for by

The vascular function curve is traditionally plotted as flow on the ordinate against the right atrial pressure on the abscissa. In this case, the slope of the linear portion of the curve is

The vascular function curve is traditionally plotted as flow on the ordinate against the right atrial pressure on the abscissa. In this case, the slope of the linear portion of the curve