AR 4. Retrieval quiz Fri 22 Nov

Which of the following best describes the sequence of electrical conduction in the heart?

• A) SA node → AV node → Purkinje fibers → Bundle of His

• B) AV node → SA node → Bundle of His → Purkinje fibers

• C) SA node → AV node → Bundle of His → Purkinje fibers

• D) Purkinje fibers → Bundle of His → SA node → AV node

Why is there a delay at the atrioventricular (AV) node during the cardiac impulse?

• A) To ensure simultaneous contraction of the atria and ventricles

• B) To allow the ventricles time to fully contract before the atria do

• C) To ensure the atria have time to fully contract and empty blood into the ventricles

• D) To prevent backward flow of blood into the atria

How does the structure of the left ventricle support its function?

• A) It has thin walls to store blood under low pressure

• B) It has thicker muscular walls to generate higher pressure for systemic circulation

• C) It contains valves that prevent backflow from the aorta into the left atrium

• D) It has a smaller chamber to increase the speed of blood flow

What physiological change occurs during the "lub-dub" sound of the heart?

• A) The "lub" sound is caused by the closure of the semilunar valves, and the "dub" is from the closure of the atrioventricular valves.

• B) The "lub" sound is caused by the opening of the atrioventricular valves, and the "dub" is from the opening of the semilunar valves.

• C) The "lub" sound is caused by the closure of the atrioventricular valves, and the "dub" is from the closure of the semilunar valves.

• D) Both sounds are caused by the contraction of the heart muscle.

Which factor does NOT directly affect cardiac output?

• A) Heart rate

• B) Stroke volume

• C) Peripheral resistance

• D) Venous return

Why is high blood pressure a risk factor for heart disease?

• A) It decreases the oxygen supply to the heart muscle.

• B) It leads to the weakening and damage of artery walls over time.

• C) It increases the ability of the heart to pump blood efficiently.

• D) It promotes greater flexibility of the arterial walls.

What mechanism helps venous blood return to the heart against gravity?

• A) High pressure in the veins

• B) The presence of one-way valves and muscle contractions

• C) The suction effect of atrial systole

• D) High oxygen levels in the blood

What is the main difference between systemic and pulmonary circulation?

• A) Systemic circulation pumps blood to the lungs, while pulmonary circulation pumps blood to the body.

• B) Systemic circulation carries oxygenated blood, while pulmonary circulation carries deoxygenated blood to the heart.

• C) Systemic circulation delivers oxygenated blood to the body, while pulmonary circulation exchanges gases in the lungs.

• D) Pulmonary circulation has a higher blood pressure than systemic circulation.

What might a blood pressure of 120/70 mmHg indicate in a young, fit person?

• Hypertension

• Normal blood pressure

• Hypotension

• Heart failure

What physiological condition can be associated with hypotension?

• High cholesterol levels

• Muscle spasms

• Shock

• Increased blood volume