Question 1

Which of the following best describes the function of the cardiac skeleton?

Accepted Answer

It provides structural support, anchors cardiac muscle fibers, and insulates electrical impulses between atria and ventricles.

Question 2

A patient has a stroke volume (SV) of 70 mL and an end systolic volume (ESV) of 50 mL. What is the end diastolic volume (EDV)? Use the formula $$SV = EDV - ESV.$$

Accepted Answer

$$EDV = 120\ \mathrm{mL}$$

Question 3

Which of the following statements about the pulmonary and systemic circuits is correct?

Accepted Answer

The pulmonary circuit is a low-pressure system that carries equal volumes of blood as the systemic circuit.

Question 4

During which phase of the cardiac cycle are all four heart valves closed and the ventricles are neither filling nor ejecting blood?

Accepted Answer

Isovolumetric contraction

Question 5

Which of the following best explains why the sinoatrial (SA) node is called the natural pacemaker of the heart?

Accepted Answer

It has the fastest rate of spontaneous depolarization, setting the rhythm for the entire heart.

Question 6

A patient has a heart rate (HR) of 80 beats per minute and a stroke volume (SV) of 65 mL. What is their cardiac output (CO)? Use the formula $$CO = HR 	imes SV.$$

Accepted Answer

$$CO = 5200\ \mathrm{mL/min}$$

Question 7

Which of the following is a key difference between cardiac muscle cells and skeletal muscle cells?

Accepted Answer

Cardiac muscle cells have a longer absolute refractory period than skeletal muscle cells.

Question 8

Which of the following best describes the role of preload in cardiac physiology?

Accepted Answer

Preload is the degree of stretch of cardiac muscle cells before contraction, directly related to venous return.

Question 9

Which of the following events is responsible for the first heart sound (S1)?

Accepted Answer

Closure of the atrioventricular (AV) valves

Question 10

A patient is experiencing increased afterload due to hypertension. What effect will this have on end systolic volume (ESV) and stroke volume (SV)?

Accepted Answer

ESV will increase and SV will decrease.

Question 11

Which of the following best describes the function of intercalated discs in cardiac muscle?

Accepted Answer

They provide electrical and mechanical connection between cardiac cells via gap junctions and desmosomes.

Question 12

Which of the following correctly matches the heart valve with its location?

Accepted Answer

The pulmonary semilunar valve is located between the right ventricle and the pulmonary trunk.

Question 13

Which of the following best explains why there is a delay at the atrioventricular (AV) node during the sequence of excitation?

Accepted Answer

To allow the atria to finish contracting and complete ventricular filling before the ventricles contract.

Question 14

Which of the following is true regarding the action potential of cardiac pacemaker cells?

Accepted Answer

The pacemaker potential is due to slow opening of sodium channels.

Question 15

Which nerve is responsible for decreasing heart rate via parasympathetic innervation?

Accepted Answer

Vagus nerve (cranial nerve X)

Question 16

Which of the following best describes the Frank-Starling Law of the Heart?

Accepted Answer

The greater the preload (stretch), the greater the force of contraction and stroke volume.

Question 17

Which of the following is the only electrical connection between the atria and ventricles?

Accepted Answer

The atrioventricular (AV) bundle (bundle of His)

Question 18

Which of the following best describes the direction of ion movement during the plateau phase of the cardiac contractile cell action potential?

Accepted Answer

Calcium ions enter the cell while potassium ions exit, maintaining a prolonged depolarization.

Question 19

Which fetal structure allows blood to bypass the lungs by connecting the right atrium to the left atrium?

Accepted Answer

Foramen ovale

Question 20

A patient has a decreased venous return due to blood loss. Which of the following changes would you expect in their cardiac output, assuming heart rate remains constant? Use the relationships $$SV = EDV - ESV$$ and $$CO = HR 	imes SV.$$

Accepted Answer

Stroke volume and cardiac output will both decrease.

Cardiac Anatomy & Physiology: Study Guide for BIOL 2114 Exam 2 (Chapter 18)

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