Question 1

Which of the following best describes the primary function of the circulatory system?

Accepted Answer

Transporting oxygen, carbon dioxide, nutrients, wastes, and hormone signals throughout the body.

Question 2

Which vessel carries oxygenated blood away from the heart to the body’s tissues?

Accepted Answer

Aorta

Question 3

What is the correct sequence of blood flow through the heart and lungs?

Accepted Answer

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

Question 4

Which statement about arterial and venous blood is correct?

Accepted Answer

Arterial blood is oxygenated except in the pulmonary artery, and venous blood is deoxygenated except in the pulmonary vein.

Question 5

What is the role of the chordae tendineae and papillary muscles in heart valve function?

Accepted Answer

They anchor the AV valves and prevent them from inverting into the atria during ventricular contraction.

Question 6

Which of the following best explains why the heart needs a separate coronary circulation?

Accepted Answer

The heart muscle is too thick for oxygen and nutrients to diffuse from the blood inside the chambers.

Question 7

Which statement about the conduction system of the heart is correct?

Accepted Answer

The SA node generates spontaneous depolarizations that trigger action potentials in surrounding cells.

Question 8

What is the main difference between cardiac muscle and skeletal muscle at the cellular level?

Accepted Answer

Cardiac muscle cells are branched, have intercalated discs, and are strictly aerobic.

Question 9

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

Accepted Answer

They allow for direct electrical and mechanical coupling between adjacent cells, enabling coordinated contraction.

Question 10

Which pacemaker generally sets the overall rate of heart contraction?

Accepted Answer

SA node

Question 11

What is the correct order of the conduction pathway for the action potential through the heart?

Accepted Answer

SA node → AV node → Bundle of His → Bundle branches → Purkinje fibers

Question 12

Which of the following is a feature unique to cardiac muscle cells?

Accepted Answer

Strictly aerobic metabolism

Question 13

Which condition is characterized by stiffened heart valves that impede blood flow and require higher pressure to open?

Accepted Answer

Stenosis

Question 14

What is the primary effect of sympathetic nervous system activation on the heart?

Accepted Answer

It increases heart rate and contractility by increasing Ca$$^{2+}$$ concentration and excitation-contraction coupling.

Question 15

Which of the following best describes the cardiac action potential compared to the skeletal muscle action potential?

Accepted Answer

Cardiac APs have a longer plateau phase due to slow Ca$$^{2+}$$ channels, which is critical for sustained contraction.

Question 16

Which wave in the ECG corresponds to ventricular contraction?

Accepted Answer

QRS complex

Question 17

What is the main function of the AV valves in the heart?

Accepted Answer

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

Question 18

Which of the following statements about pacemaker cells is correct?

Accepted Answer

They generate spontaneous depolarizations that trigger action potentials in surrounding cells.

Question 19

Which of the following is a consequence of heart valve insufficiency?

Accepted Answer

Backflow of blood and increased workload on the heart.

Question 20

Which of the following best describes the role of the Purkinje fibers in the heart?

Accepted Answer

They carry the impulse rapidly through the ventricles, ensuring coordinated ventricular contraction.

BIO EXAM 3A

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