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

Question 1

Which layer of the heart wall is primarily responsible for the contractile function of the heart?

Accepted Answer

Myocardium

Question 2

A patient presents with chest pain due to reduced blood flow to the myocardium. What is the most likely diagnosis?

Accepted Answer

Angina pectoris

Question 3

Which of the following best describes the flow of blood through the heart?

Accepted Answer

Right atrium → right ventricle → pulmonary artery → lungs → pulmonary veins → left atrium → left ventricle → aorta

Question 4

Which heart valve prevents backflow of blood from the left ventricle to the left atrium?

Accepted Answer

Mitral (bicuspid) valve

Question 5

During which phase of the cardiac cycle are both the AV and SL valves closed, and ventricular pressure is changing but volume remains constant?

Accepted Answer

Isovolumetric contraction phase

Question 6

Which of the following equations correctly represents cardiac output?

Accepted Answer

$$CO = HR 	imes SV$$

Question 7

A patient has an end diastolic volume (EDV) of 120 mL and an end systolic volume (ESV) of 50 mL. What is the stroke volume (SV)?

Accepted Answer

$$SV = EDV - ESV = 70\ \mathrm{mL}$$

Question 8

Which of the following statements about the Frank-Starling Law is correct?

Accepted Answer

Increased venous return leads to increased stroke volume due to optimal overlap of actin and myosin

Question 9

Which component of the cardiac conduction system is known as the pacemaker of the heart?

Accepted Answer

Sinoatrial (SA) node

Question 10

What does the QRS complex on an electrocardiogram (ECG) represent?

Accepted Answer

Ventricular depolarization

Question 11

Which of the following would most likely increase heart rate?

Accepted Answer

Increased epinephrine levels

Question 12

A patient with persistent high blood pressure is at risk for which cardiac condition due to increased afterload?

Accepted Answer

Congestive heart failure (CHF)

Question 13

Which of the following best explains why tetanic contractions do not occur in cardiac muscle?

Accepted Answer

Cardiac muscle cells have a long refractory period that prevents summation

Question 14

If the AV node is defective and no impulses reach the ventricles, what is the likely outcome?

Accepted Answer

Ventricles beat at their own intrinsic rate, which is too slow to maintain adequate circulation

Question 15

Which of the following is a function of the chordae tendineae?

Accepted Answer

Prevent AV valves from bulging into the atria during ventricular contraction

Question 16

Which of the following would decrease stroke volume?

Accepted Answer

Decreased venous return

Question 17

A patient has a heart rate of 80 beats/min and a stroke volume of 70 mL/beat. What is the cardiac output?

Accepted Answer

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

Question 18

Which of the following best describes the role of the coronary circulation?

Accepted Answer

Provides blood supply to the heart muscle itself

Question 19

Which of the following would most likely result from valvular stenosis?

Accepted Answer

Valve fails to open completely, restricting blood flow and increasing cardiac workload

Question 20

Which of the following events occurs first in the cardiac cycle?

Accepted Answer

Atrial systole

Chapter 18: The Heart – Anatomy & Physiology Study Notes

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