Question 1

Which of the following best describes the path of blood flow through the mammalian heart and major vessels during double circulation?

Accepted Answer

Right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta → body

Question 2

What is the primary function of the atrioventricular (AV) valves in the heart?

Accepted Answer

To prevent backflow of blood from the ventricles into the atria during ventricular contraction

Question 3

During which phase of the cardiac cycle does the heart fill with blood?

Accepted Answer

Diastole

Question 4

Which structure acts as the pacemaker of the mammalian heart?

Accepted Answer

Sinoatrial (SA) node

Question 5

If a patient has a defective semilunar valve, what is the most likely consequence?

Accepted Answer

Blood may flow back into the ventricle from the aorta or pulmonary artery after ventricular contraction

Question 6

Which of the following equations correctly represents cardiac output ($$CO$$)?

Accepted Answer

$$CO = HR 	imes SV$$

Question 7

A molecule of carbon dioxide produced in the leg muscle will pass through how many capillary beds before it is exhaled from the lungs?

Accepted Answer

Two

Question 8

Which event is responsible for the 'lub' sound heard during a heartbeat?

Accepted Answer

Closing of the atrioventricular (AV) valves

Question 9

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

Accepted Answer

It must generate more force to pump blood throughout the systemic circuit

Question 10

Which of the following best explains why the two ventricles of the heart pump the same volume of blood during each contraction?

Accepted Answer

To maintain equal blood flow through both the pulmonary and systemic circuits

Question 11

Which of the following would most likely increase the heart rate?

Accepted Answer

Increased secretion of epinephrine

Question 12

A patient’s ECG shows a prolonged delay between atrial and ventricular contraction. Which structure is most likely malfunctioning?

Accepted Answer

Atrioventricular (AV) node

Question 13

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

Accepted Answer

They allow electrical impulses to spread rapidly between cardiac muscle cells

Question 14

If the sympathetic division of the nervous system is activated, what is the expected effect on the heart?

Accepted Answer

Increased heart rate

Question 15

Which of the following is a direct result of the delay at the AV node during the cardiac cycle?

Accepted Answer

The atria have time to fully contract and empty their blood into the ventricles before the ventricles contract

Question 16

A patient is diagnosed with a heart murmur. Which of the following is the most likely cause?

Accepted Answer

Blood flowing backward through a defective valve

Question 17

Which of the following best explains why the systemic circuit contains a greater total volume of blood than the pulmonary circuit?

Accepted Answer

The systemic circuit supplies blood to the entire body except the lungs

Question 18

Which of the following would be the immediate effect if the Purkinje fibers were damaged?

Accepted Answer

Ventricular contraction would be uncoordinated or delayed

Question 19

If a person’s body temperature increases by $$1^{\circ}C$, what is the expected effect on their heart rate?

Accepted Answer

Heart rate increases

Question 20

Which of the following best describes the function of the semilunar valves?

Accepted Answer

They prevent backflow of blood from the arteries into the ventricles

Coordinated Cycles of Heart Contraction and Double Circulation in Mammals

Study Guide - Practice Questions