Q: Which equation correctly represents cardiac output, and what are the typical resting values for heart rate and stroke volume in adults?

$$CO = HR \times SV$$; HR = 75 bpm, SV = 70 ml/beat

Q: A patient with a heart rate of 120 bpm and a stroke volume of 50 ml/beat has what cardiac output?

$$CO = 120 \times 50 = 6000 ml/$$min

Question 1

Which layer of the heart wall is responsible for the contraction of the heart, and what cellular structures facilitate the spread of electrical impulses across this layer?

Accepted Answer

Myocardium; intercalated discs with gap junctions

Question 2

During ventricular systole, which valves are open and which are closed, and what is the physiological significance of this arrangement?

Accepted Answer

AV valves closed, semilunar valves open; prevents backflow into atria and allows ejection into arteries

Question 3

A patient presents with swelling in the feet and ankles. Which side of the heart is most likely failing, and what is the underlying mechanism?

Accepted Answer

Right side; peripheral congestion due to blood backing up in systemic circulation

Question 4

Which equation correctly represents cardiac output, and what are the typical resting values for heart rate and stroke volume in adults?

Accepted Answer

$$CO = HR 	imes SV$$; HR = 75 bpm, SV = 70 ml/beat

Question 5

Which of the following best describes the function of the pulmonary circuit?

Accepted Answer

Carries oxygen-poor blood from the right ventricle to the lungs for gas exchange

Question 6

A patient with a heart rate of 120 bpm and a stroke volume of 50 ml/beat has what cardiac output?

Accepted Answer

$$CO = 120 	imes 50 = 6000 ml/$$min

Question 7

Which of the following factors increases stroke volume according to the Frank-Starling law?

Accepted Answer

Increased stretching of cardiac muscle cells (preload)

Question 8

Which vessel carries oxygen-rich blood from the lungs to the left atrium?

Accepted Answer

Pulmonary vein

Question 9

What is the primary function of the valves in veins, and how does skeletal muscle activity assist this function?

Accepted Answer

Valves prevent backflow; skeletal muscle contraction 'milks' blood toward the heart

Question 10

Which structure is the pacemaker of the heart, and what is its role in the intrinsic conduction system?

Accepted Answer

Sinoatrial (SA) node; initiates heartbeat and sets the pace for the heart

Question 11

During the cardiac cycle, what causes the 'lub' sound heard with a stethoscope?

Accepted Answer

Closing of the atrioventricular (AV) valves

Question 12

Which of the following is a consequence of valvular stenosis in the heart?

Accepted Answer

Stiff valve cusps, increased heart workload, and eventual heart failure

Question 13

Which equation best represents the relationship between blood pressure, cardiac output, and peripheral resistance?

Accepted Answer

$$BP = CO 	imes PR$$

Question 14

Which of the following best explains why the left ventricle has a thicker wall than the right ventricle?

Accepted Answer

It pumps blood through the systemic circuit, which is a longer and higher-resistance pathway

Question 15

Which of the following is NOT a route by which substances can cross capillary walls?

Accepted Answer

Active transport via sodium-potassium pump

Question 16

A patient with a blood pressure of 150/95 mm Hg is diagnosed with hypertension. Which of the following is a potential long-term consequence of untreated hypertension?

Accepted Answer

Increased risk of heart failure and damage to blood vessels

Question 17

Which of the following best describes the effect of sympathetic nervous system activation on blood vessels during exercise?

Accepted Answer

Generalized vasoconstriction except in skeletal muscles, which dilate

Question 18

Which structure allows blood to bypass the fetal lungs by connecting the pulmonary trunk and the aorta?

Accepted Answer

Ductus arteriosus

Question 19

Which of the following is a major function of the hepatic portal circulation?

Accepted Answer

Allows nutrient-rich blood from digestive organs to be processed by the liver before entering systemic circulation

Question 20

Which physical factor increases heart rate by boosting the metabolic rate of heart cells?

Accepted Answer

Heat (e.g., fever or exercise)

Chapter 11: The Cardiovascular System – Structure, Function, and Physiology

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