Q: A patient has an end-diastolic volume (EDV) of 130 mL and an end-systolic volume (ESV) of 60 mL. If their heart rate (HR) is 75 beats per minute, what is their cardiac output (CO)? Use the formula $$CO = HR \times SV$$ and $$SV = EDV - ESV.$$

$$CO = 75 \times (130 - 60) = 75 \times 70 = 5,250 mL/$$min = 5.25 L/min

Q: A patient has a stroke volume (SV) of 80 mL and an end-diastolic volume (EDV) of 120 mL. What is their ejection fraction (EF)? Use the formula $$EF = \frac{SV}{EDV} \times 100\%.$$

$$EF = \frac{80}{120} \times 100\% = 66.7\%$$

Question 1

A patient is diagnosed with cardiac tamponade after a car accident. Which of the following best explains why cardiac tamponade reduces cardiac output?

Accepted Answer

Excess fluid in the pericardial cavity compresses the heart, limiting ventricular filling during diastole.

Question 2

Which of the following correctly traces the path of a red blood cell from the right atrium to the left ventricle?

Accepted Answer

Right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary trunk → lungs → pulmonary veins → left atrium → mitral valve → left ventricle

Question 3

A patient has an end-diastolic volume (EDV) of 130 mL and an end-systolic volume (ESV) of 60 mL. If their heart rate (HR) is 75 beats per minute, what is their cardiac output (CO)? Use the formula $$CO = HR 	imes SV$$ and $$SV = EDV - ESV.$$

Accepted Answer

$$CO = 75 	imes (130 - 60) = 75 	imes 70 = 5,250 mL/$$min = 5.25 L/min

Question 4

Which of the following best describes the function of the chordae tendineae in the heart?

Accepted Answer

They prevent the atrioventricular valve cusps from everting into the atria during ventricular contraction.

Question 5

A patient’s ECG shows a prolonged P–R interval. Which part of the cardiac conduction system is most likely affected?

Accepted Answer

AV node

Question 6

Which of the following statements about the myocardium is correct?

Accepted Answer

It is the thickest layer of the heart wall and is responsible for the heart’s contractile force.

Question 7

During which phase of the cardiac cycle are all heart valves closed and the ventricles begin to contract, but no blood is ejected?

Accepted Answer

Isovolumetric contraction

Question 8

A patient has a stroke volume (SV) of 80 mL and an end-diastolic volume (EDV) of 120 mL. What is their ejection fraction (EF)? Use the formula $$EF = \frac{SV}{EDV} 	imes 100\%.$$

Accepted Answer

$$EF = \frac{80}{120} 	imes 100\% = 66.7\%$$

Question 9

Which of the following best explains why the left ventricular wall is thicker than the right ventricular wall?

Accepted Answer

The left ventricle must generate higher pressure to pump blood through the systemic circuit.

Question 10

Which of the following would most likely result in a heart murmur?

Accepted Answer

A defective mitral valve causing turbulent blood flow between the left atrium and left ventricle.

Question 11

Which of the following best describes the effect of increased preload on stroke volume, according to the Frank–Starling law?

Accepted Answer

Increased preload stretches the ventricular muscle, resulting in a stronger contraction and increased stroke volume.

Question 12

A patient is given a drug that blocks sympathetic stimulation of the heart. Which of the following changes would you expect?

Accepted Answer

Decreased heart rate and decreased contractility

Question 13

Which of the following is the correct sequence of electrical conduction through the heart?

Accepted Answer

SA node → AV node → AV bundle → bundle branches → Purkinje fibers

Question 14

Which of the following best describes the role of gap junctions in cardiac muscle?

Accepted Answer

They allow ions and electrical impulses to pass directly between adjacent cells, enabling coordinated contraction.

Question 15

A patient’s ECG shows an abnormally tall and wide QRS complex. Which of the following is most likely occurring in the heart?

Accepted Answer

Ventricular depolarization is abnormal, possibly due to a bundle branch block.

Question 16

Which hormone is released by the atria and helps lower blood pressure by decreasing sodium and water retention?

Accepted Answer

Atrial natriuretic peptide (ANP)

Question 17

A patient with a heart rate of 90 beats per minute and a stroke volume of 60 mL/beat has a cardiac output of:

Accepted Answer

$$CO = 90 	imes 60 = 5,400 mL/$$min = 5.4 L/min

Question 18

Which of the following would most likely increase afterload and decrease stroke volume?

Accepted Answer

High blood pressure in the aorta

Question 19

Which of the following best explains why the heart can continue to beat even when removed from the body and placed in a nutrient solution?

Accepted Answer

The heart has autorhythmic pacemaker cells that generate spontaneous action potentials.

Question 20

A patient is found to have a blockage in the left anterior descending (LAD) artery. Which area of the heart is most at risk for ischemia?

Accepted Answer

Anterior wall of the left ventricle

The Heart: Structure, Function, and Physiology

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