Question 1

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

Accepted Answer

Open circulatory systems use hemolymph that bathes organs directly, while closed circulatory systems confine blood to vessels.

Question 2

A fish has a single circulation system. What is a major consequence of this arrangement?

Accepted Answer

Blood pressure drops significantly after passing through the gill capillaries, resulting in slower delivery to body tissues.

Question 3

Which of the following equations correctly represents cardiac output ($$CO) in $$terms of heart rate ($$HR) $$and stroke volume ($$SV$$)?

Accepted Answer

$$CO = HR 	imes SV$$

Question 4

In mammals, which heart chamber receives oxygen-rich blood from the lungs?

Accepted Answer

Left atrium

Question 5

Which of the following best explains why arteries have thicker walls than veins?

Accepted Answer

Arteries must withstand higher pressure generated by the heart's contractions.

Question 6

Which of the following is a function of the lymphatic system in relation to the circulatory system?

Accepted Answer

It returns excess interstitial fluid to the bloodstream and helps filter pathogens.

Question 7

A patient has a blood pressure reading of 130/80 mm Hg. What does the 80 mm Hg value represent?

Accepted Answer

Diastolic pressure, the pressure in the arteries during ventricular relaxation.

Question 8

Which of the following best describes the Bohr shift?

Accepted Answer

A decrease in blood pH lowers hemoglobin's affinity for oxygen, enhancing oxygen release to tissues.

Question 9

Which of the following is the primary mechanism by which oxygen is transported in the blood?

Accepted Answer

Bound to hemoglobin within erythrocytes

Question 10

Which of the following statements about capillary exchange is correct?

Accepted Answer

Fluid leaves capillaries at the arterial end due to higher blood pressure and re-enters at the venous end due to higher osmotic pressure.

Question 11

Which of the following best describes the path of a red blood cell starting in the right atrium of a human heart?

Accepted Answer

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

Question 12

Which of the following is a correct statement about the control of breathing in humans?

Accepted Answer

The medulla oblongata adjusts breathing rate in response to changes in pH of cerebrospinal fluid.

Question 13

Which of the following is a real-world consequence of a thrombus forming in a coronary artery?

Accepted Answer

It can block blood flow to heart muscle, causing a heart attack.

Question 14

Which of the following best explains why aquatic animals require more efficient respiratory systems than terrestrial animals?

Accepted Answer

Oxygen concentration is much lower in water than in air.

Question 15

Which of the following is a function of platelets in the blood?

Accepted Answer

Initiating blood clotting by forming a temporary plug at the site of vessel injury

Question 16

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

Accepted Answer

They regulate blood flow into capillary beds by opening or closing in response to local signals.

Question 17

Which of the following equations correctly represents the relationship between partial pressure, concentration, and gas exchange?

Accepted Answer

Gases diffuse from regions of higher partial pressure to regions of lower partial pressure.

Question 18

Which of the following is a correct statement about the mammalian heart valves?

Accepted Answer

Atrioventricular (AV) valves prevent backflow of blood from the ventricles to the atria.

Question 19

Which of the following best explains why blood flow velocity is slowest in the capillaries?

Accepted Answer

The total cross-sectional area of capillaries is much greater than that of arteries or veins.

Circulation and Gas Exchange: Structure and Function of Animal Circulatory Systems

Study Guide - Practice Questions