Question 1

Which of the following best explains why the left ventricle of the heart has a thicker wall than the right ventricle?

Accepted Answer

Because it pumps blood to the entire systemic circuit, requiring higher pressure to reach distant tissues.

Question 2

During which phase of the cardiac cycle are the atrioventricular (AV) valves open and the semilunar valves closed?

Accepted Answer

Late diastole

Question 3

A patient has a defect in their semilunar valves, causing them to not close properly. Which of the following is the most likely consequence?

Accepted Answer

Blood will flow backward from the arteries into the ventricles during ventricular relaxation.

Question 4

Which of the following statements about veins is correct?

Accepted Answer

Veins carry blood toward the heart, regardless of oxygenation status.

Question 5

What is the primary physiological reason for the presence of coronary arteries in the heart?

Accepted Answer

To provide oxygen and nutrients directly to cardiac muscle cells, which cannot obtain sufficient oxygen from the blood inside the heart chambers.

Question 6

Which of the following best describes the relationship between pressure and volume in the heart during ventricular contraction?

Accepted Answer

As ventricular volume decreases, pressure increases.

Question 7

A person is exercising, and their stroke volume increases. Which of the following best explains this change?

Accepted Answer

End diastolic volume increases and end systolic volume decreases, resulting in a larger difference between the two.

Question 8

Which of the following equations correctly represents the calculation of stroke volume ($$SV) in $$the heart?

Accepted Answer

$$SV = EDV - ESV$$

Question 9

During the cardiac cycle, what event is responsible for the first heart sound ('lub')?

Accepted Answer

Closing of the atrioventricular (AV) valves during isovolumic contraction

Question 10

Which of the following best explains why the action potential in cardiac muscle cells has a plateau phase?

Accepted Answer

To ensure the refractory period lasts as long as the contraction, preventing summation and tetanus.

Question 11

Which ion is primarily responsible for the plateau phase of the cardiac muscle action potential?

Accepted Answer

Calcium ($$Ca^{2+})$$

Question 12

A patient has a mutation that causes their fast-opening potassium channels in cardiac myocytes to remain open longer than normal. What is the most likely effect on the cardiac action potential?

Accepted Answer

The initial repolarization will be exaggerated, and the plateau phase will be shortened.

Question 13

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

Accepted Answer

They provide structural support and allow electrical coupling between cells via gap junctions.

Question 14

If the atria fail to contract (atrial systole is absent), what is the most likely immediate effect on ventricular filling?

Accepted Answer

Ventricular filling will be reduced, but not eliminated, because most filling occurs passively during diastole.

Question 15

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

Accepted Answer

The systemic circuit requires higher pressure to deliver blood throughout the body.

Question 16

Which of the following best describes the direction of blood flow through the heart and major vessels?

Accepted Answer

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

Question 17

Which of the following is a correct statement about the refractory period in cardiac muscle cells?

Accepted Answer

It lasts almost as long as the contraction, preventing tetanus.

Question 18

A patient is found to have a mean arterial pressure (MAP) of 100 mmHg, a systolic pressure of 130 mmHg, and a diastolic pressure of 80 mmHg. Which of the following equations can be used to estimate MAP?

Accepted Answer

$$MAP = Diastolic + \frac{1}{3}(Systolic - Diastolic)$$

Question 19

Which of the following best explains why blood in the pulmonary veins is oxygenated?

Accepted Answer

Because the pulmonary veins return blood from the lungs to the heart after gas exchange has occurred.

Question 20

Which of the following animals has blue blood due to the presence of hemocyanin?

Accepted Answer

Horseshoe crab

The Cardiovascular System: Structure, Function, and Cardiac Muscle Physiology

Guida di studio - Domande di pratica

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