Q: Which of the following best describes the ionic mechanism responsible for the pacemaker potential in the SA node?

A gradual depolarization due to slow Na\textsuperscript{+} influx and decreased K\textsuperscript{+} efflux

Q: Which phase of the cardiac contractile cell action potential is responsible for the plateau, and what ion movement causes it?

Phase 2; sustained Ca\textsuperscript{2+} influx

Q: A patient has a stroke volume of 70 mL and a heart rate of 80 beats per minute. What is their cardiac output?

$$CO = 70 \times 80 = 5600\ \text{mL/min}$$

Question 1

Which of the following best describes the ionic mechanism responsible for the pacemaker potential in the SA node?

Accepted Answer

A gradual depolarization due to slow Na	extsuperscript{+} influx and decreased K	extsuperscript{+} efflux

Question 2

If the SA node fails, which structure typically takes over as the pacemaker of the heart, and how does its intrinsic rate compare to the SA node?

Accepted Answer

The AV node; it has a slower intrinsic rate than the SA node

Question 3

Which phase of the cardiac contractile cell action potential is responsible for the plateau, and what ion movement causes it?

Accepted Answer

Phase 2; sustained Ca	extsuperscript{2+} influx

Question 4

During the cardiac cycle, which event coincides with the QRS complex on an EKG?

Accepted Answer

Ventricular depolarization

Question 5

Which equation correctly represents the relationship between cardiac output (CO), stroke volume (SV), and heart rate (HR)?

Accepted Answer

$$CO = SV 	imes HR$$

Question 6

A patient has a stroke volume of 70 mL and a heart rate of 80 beats per minute. What is their cardiac output?

Accepted Answer

$$CO = 70 	imes 80 = 5600\ 	ext{mL/min}$$

Question 7

Which of the following best explains why the lymphatic system is essential for preventing constant edema in tissues?

Accepted Answer

It returns excess interstitial fluid to the bloodstream

Question 8

Which blood vessel type has the highest pressure and thickest wall, and what is its primary function?

Accepted Answer

Arteries; to withstand and distribute high-pressure blood from the heart

Question 9

Which formula correctly expresses the relationship between blood flow (F), pressure difference ($$\Delta P$$), and resistance (R)?

Accepted Answer

$$F = \dfrac{\Delta P}{R}$$

Question 10

Rank the following sources of resistance in blood vessels from greatest to least impact under normal physiological conditions: vessel diameter, blood viscosity, vessel length.

Accepted Answer

Vessel diameter \u003e vessel length \u003e blood viscosity

Question 11

A patient’s blood pressure is measured as 120/80 mm Hg. What is their pulse pressure and mean arterial pressure (MAP)?

Accepted Answer

Pulse pressure: $$120 - 80 = 40 mm Hg$$; MAP: $$80 + \dfrac{40}{3} = 93.3 mm Hg$$

Question 12

Which type of capillary is most likely to be found in the liver and allows the greatest movement of large molecules?

Accepted Answer

Sinusoidal capillary

Question 13

Which mechanism is primarily responsible for the movement of oxygen from blood to tissue fluid in capillaries?

Accepted Answer

Diffusion

Question 14

Calculate the net filtration pressure (NFP) at the arterial end of a capillary given: capillary hydrostatic pressure = 35 mm Hg, capillary osmotic pressure = 25 mm Hg, interstitial fluid hydrostatic pressure = 0 mm Hg, interstitial fluid osmotic pressure = 2 mm Hg.

Accepted Answer

$$NFP = (35 + 2) - (25 + 0) = 12 mm Hg$$

Question 15

Which of the following would most likely increase the risk of edema?

Accepted Answer

Increased capillary hydrostatic pressure

Question 16

Which of the following best describes the function of veins in the cardiovascular system?

Accepted Answer

They serve as blood volume reservoirs and return blood to the heart

Question 17

Which equation correctly expresses the relationship between mean arterial pressure (MAP), cardiac output (CO), and peripheral resistance (PR)?

Accepted Answer

$$MAP = CO 	imes PR$$

Question 18

Which of the following is a major function of the lymphatic system?

Accepted Answer

Returning excess interstitial fluid to the bloodstream

Question 19

Which lymphoid organ is primarily responsible for the maturation of T lymphocytes?

Accepted Answer

Thymus

Question 20

A patient with a blocked hepatic portal vein would most likely experience impaired drainage of blood from which organ?

Accepted Answer

Liver

Cardiovascular and Lymphatic Systems: Study Guide for A&P II

Study Guide - Practice Questions

Study Guide - Flashcards