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

$$CO = \text{Heart Rate} \times \text{Stroke Volume}$$

Question 1

Which of the following best describes the main difference between open and closed circulatory systems?

Accepted Answer

Open circulatory systems have a tubular heart and open-ended vessels, allowing hemolymph to bathe tissues directly, while closed systems confine blood to vessels, keeping it distinct from interstitial fluid.

Question 2

A patient has a blood pressure reading of 150/95 mm Hg. According to the American Heart Association guidelines, which category does this reading fall into?

Accepted Answer

Stage 2 Hypertension

Question 3

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

Accepted Answer

$$CO = 	ext{Heart Rate} 	imes 	ext{Stroke Volume}$$

Question 4

Which vessel type is primarily responsible for the exchange of gases and nutrients with tissues, and why?

Accepted Answer

Capillaries, because their thin walls allow substances to cross easily between blood and interstitial fluid.

Question 5

A person experiences a blockage in a coronary artery. What is the most likely immediate consequence?

Accepted Answer

A heart attack due to damage or death of cardiac muscle tissue.

Question 6

Which of the following best explains why albumin is important in capillary exchange?

Accepted Answer

Albumin maintains a strong osmotic gradient by keeping blood solute concentrations high, drawing fluid back into capillaries.

Question 7

Which of the following scenarios would most likely result in edema (swelling) in the tissues?

Accepted Answer

Decreased plasma protein concentration, reducing osmotic pressure and allowing more fluid to remain in the interstitial space.

Question 8

Which structure in the heart acts as the pacemaker, and what is its primary function?

Accepted Answer

The SA node; it generates electrical impulses and sets the rate of heart contractions.

Question 9

A fish has a two-chambered heart and a single circulation system. What is a key limitation of this arrangement compared to the double circulation found in mammals?

Accepted Answer

Blood pressure drops significantly after passing through the gills, limiting the speed and efficiency of systemic circulation.

Question 10

Which of the following best describes the role of precapillary sphincters?

Accepted Answer

They control the flow of blood into capillary beds, thus regulating tissue perfusion.

Question 11

A patient is found to have a high number of red blood cells due to synthetic erythropoietin injections. What is a potential risk associated with this practice?

Accepted Answer

Increased risk of blood clotting, stroke, or heart failure.

Question 12

Which of the following is the correct sequence of events during the cardiac cycle?

Accepted Answer

Atria contract, ventricles contract, heart relaxes.

Question 13

Which of the following is a direct effect of atherosclerosis in coronary arteries?

Accepted Answer

Narrowing of arterial passages due to plaque buildup, reducing blood flow to the heart muscle.

Question 14

Which of the following best explains why veins have valves, but arteries do not?

Accepted Answer

Valves in veins prevent backflow of blood as it returns to the heart under low pressure.

Question 15

Which of the following statements about blood pressure is correct?

Accepted Answer

Blood pressure is the force blood exerts on vessel walls and depends on cardiac output and vessel resistance.

Question 16

Which of the following best describes the function of platelets in the blood?

Accepted Answer

They are involved in the process of blood clotting by adhering to damaged vessels and helping convert fibrinogen to fibrin.

Question 17

A person with a genetic defect that prevents the production of fibrinogen would most likely experience which of the following?

Accepted Answer

Difficulty forming blood clots, leading to excessive bleeding.

Question 18

Which of the following best explains why the lymphatic system is necessary for circulatory function?

Accepted Answer

It returns excess fluid and proteins from the interstitial space back to the circulatory system, maintaining fluid balance.

Question 19

Which of the following is a correct statement about the evolutionary adaptation of vertebrate hearts?

Accepted Answer

Amphibians and many reptiles have three-chambered hearts, while birds and mammals have four-chambered hearts.

Circulation: Structure and Function of the Cardiovascular System

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