$$SV = 120 - 50 = 70\ \text{mL}$$

$$CO = 90 \times 60 = 5400\ \text{mL/min}$$

Question 1

Which layer of the heart wall contains the bulk of the cardiac muscle and is responsible for contraction?

Accepted Answer

Myocardium

Question 2

A patient presents with chest pain due to a temporary lack of oxygen to the myocardium. What is the most likely diagnosis?

Accepted Answer

Angina pectoris

Question 3

During ventricular systole, which heart sound is heard and what causes it?

Accepted Answer

Lub (S1), caused by closure of AV valves

Question 4

Which equation correctly calculates cardiac output (CO)?

Accepted Answer

$$CO = HR 	imes SV$$

Question 5

If a patient has an end diastolic volume (EDV) of 120 mL and an end systolic volume (ESV) of 50 mL, what is their stroke volume (SV)?

Accepted Answer

$$SV = 120 - 50 = 70\ 	ext{mL}$$

Question 6

Which structure is the heart's natural pacemaker, and what is its typical rate?

Accepted Answer

SA node, ~75 bpm

Question 7

Which coronary artery supplies the anterior interventricular septum and anterior walls of the ventricles?

Accepted Answer

Left anterior interventricular (LAD) artery

Question 8

During the cardiac cycle, when are all four heart valves closed?

Accepted Answer

During isovolumetric contraction and isovolumetric relaxation

Question 9

Which of the following best describes the Frank-Starling law of the heart?

Accepted Answer

Increased preload (stretch) leads to stronger contraction and increased stroke volume

Question 10

A patient with hypertension has an increased afterload. What effect does this have on stroke volume (SV) and end systolic volume (ESV)?

Accepted Answer

SV decreases, ESV increases

Question 11

Which ion is primarily responsible for the plateau phase in the action potential of cardiac contractile cells?

Accepted Answer

Ca$$^{2+}$$ influx through slow channels

Question 12

What is the main reason the left ventricle wall is much thicker than the right ventricle wall?

Accepted Answer

It pumps blood through a longer, higher-resistance systemic circuit

Question 13

Which of the following statements about cardiac muscle is TRUE?

Accepted Answer

Cardiac muscle contracts as a unit due to gap junctions in intercalated discs

Question 14

Which part of the ECG corresponds to ventricular depolarization?

Accepted Answer

QRS complex

Question 15

A patient has a heart rate (HR) of 90 bpm and a stroke volume (SV) of 60 mL. What is their cardiac output (CO)?

Accepted Answer

$$CO = 90 	imes 60 = 5400\ 	ext{mL/min}$$

Question 16

Which of the following would most likely cause a 'swishing' heart murmur?

Accepted Answer

Incompetent (insufficient) valve

Question 17

Which of the following best describes the effect of the parasympathetic nervous system on heart rate?

Accepted Answer

It decreases heart rate by releasing acetylcholine

Question 18

During ventricular ejection, which valves are open and what is the approximate pressure in the aorta?

Accepted Answer

Semilunar valves are open; aortic pressure is ~120 mmHg

Question 19

Which of the following is TRUE regarding the flow of blood through the heart?

Accepted Answer

Pulmonary arteries carry O2-poor blood to the lungs

Question 20

A patient with left-sided heart failure is most likely to develop which clinical complication?

Accepted Answer

Pulmonary congestion/edema

Chapter 18: The Heart – Anatomy & Physiology Study Guide

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