Bio 253 Final Exam Complete Study Guide Exam
Questions & Correct Verified Answers | Latest
Updated 2026 | Graded A+
Section 1: Cardiovascular System (Heart & Blood Flow)
Question 1
When does the tricuspid valve close?
A. When the right atrium contracts
B. When the right ventricle contracts
C. During atrial diastole
D. When the ventricles are relaxed
Correct Answer: B. When the right ventricle contracts
Rationale: The tricuspid valve closes at the beginning of ventricular
systole (right ventricular contraction) to prevent backflow of blood
from the right ventricle into the right atrium.
Question 2
When does the tricuspid valve open?
A. During ventricular systole
B. During diastole (ventricular relaxation)
C. When the semilunar valves open
D. During atrial contraction only
Correct Answer: B. During diastole (ventricular relaxation)
Rationale: The tricuspid valve opens when the ventricular pressure
,drops below atrial pressure during diastole, allowing blood to flow from
the right atrium into the relaxed right ventricle.
Question 3
When does the pulmonary semilunar valve open?
A. When atrial pressure exceeds ventricular pressure
B. During atrial systole
C. When pressure in the right ventricle exceeds pressure in the
pulmonary artery
D. When the ventricles are relaxed
Correct Answer: C. When pressure in the right ventricle exceeds
pressure in the pulmonary artery
Rationale: The pulmonary valve opens during ventricular systole once
the ventricular pressure overcomes the arterial pressure, ejecting
blood into the pulmonary trunk.
Question 4
When does the pulmonary semilunar valve close?
A. When the right ventricle contracts
B. During atrial systole
C. When pressure in the pulmonary artery is greater than pressure in
the right ventricle
D. When the atria are in diastole
Correct Answer: C. When pressure in the pulmonary artery is
greater than pressure in the right ventricle
Rationale: The pulmonary valve closes at the beginning of ventricular
diastole when the ventricular pressure drops below the arterial
pressure, preventing backflow into the ventricle.
,Question 5
When does the bicuspid (mitral) valve close?
A. When the left atrium contracts
B. When the left ventricle contracts
C. During ventricular diastole
D. When the aortic valve opens
Correct Answer: B. When the left ventricle contracts
Rationale: The mitral valve closes during left ventricular systole to
prevent blood from regurgitating back into the left atrium.
Question 6
When does the mitral valve open?
A. When ventricular pressure exceeds atrial pressure
B. During ventricular systole
C. When ventricular pressure drops below atrial pressure
D. When the semilunar valves close
Correct Answer: C. When ventricular pressure drops below atrial
pressure
Rationale: The mitral valve opens during diastole, allowing oxygenated
blood from the left atrium to fill the relaxed left ventricle.
Question 7
When do the semilunar valves open?
A. When atrial pressure exceeds ventricular pressure
B. When pressure in the ventricles exceeds pressure in the arteries
C. During ventricular diastole
D. When the AV valves are open
Correct Answer: B. When pressure in the ventricles exceeds
, pressure in the arteries
Rationale: This pressure gradient forces the aortic and pulmonary
valves open during the ejection phase of systole.
Question 8
When do the semilunar valves close?
A. During ventricular systole
B. When the atria contract
C. When pressure in the arteries is greater than pressure in the
ventricles
D. When the AV valves close
Correct Answer: C. When pressure in the arteries is greater than
pressure in the ventricles
Rationale: This occurs at the onset of diastole, preventing blood from
flowing back into the ventricles from the aorta and pulmonary trunk.
Question 9
What is the function of the pulmonary circuit?
A. Carries blood to the body tissues
B. Carries blood to the lungs for gas exchange and returns it to the
heart
C. Carries deoxygenated blood only
D. Carries oxygenated blood only
Correct Answer: B. Carries blood to the lungs for gas exchange
and returns it to the heart
Rationale: The pulmonary circuit is a low-pressure system that
oxygenates blood by exposing it to alveolar gas exchange.
Questions & Correct Verified Answers | Latest
Updated 2026 | Graded A+
Section 1: Cardiovascular System (Heart & Blood Flow)
Question 1
When does the tricuspid valve close?
A. When the right atrium contracts
B. When the right ventricle contracts
C. During atrial diastole
D. When the ventricles are relaxed
Correct Answer: B. When the right ventricle contracts
Rationale: The tricuspid valve closes at the beginning of ventricular
systole (right ventricular contraction) to prevent backflow of blood
from the right ventricle into the right atrium.
Question 2
When does the tricuspid valve open?
A. During ventricular systole
B. During diastole (ventricular relaxation)
C. When the semilunar valves open
D. During atrial contraction only
Correct Answer: B. During diastole (ventricular relaxation)
Rationale: The tricuspid valve opens when the ventricular pressure
,drops below atrial pressure during diastole, allowing blood to flow from
the right atrium into the relaxed right ventricle.
Question 3
When does the pulmonary semilunar valve open?
A. When atrial pressure exceeds ventricular pressure
B. During atrial systole
C. When pressure in the right ventricle exceeds pressure in the
pulmonary artery
D. When the ventricles are relaxed
Correct Answer: C. When pressure in the right ventricle exceeds
pressure in the pulmonary artery
Rationale: The pulmonary valve opens during ventricular systole once
the ventricular pressure overcomes the arterial pressure, ejecting
blood into the pulmonary trunk.
Question 4
When does the pulmonary semilunar valve close?
A. When the right ventricle contracts
B. During atrial systole
C. When pressure in the pulmonary artery is greater than pressure in
the right ventricle
D. When the atria are in diastole
Correct Answer: C. When pressure in the pulmonary artery is
greater than pressure in the right ventricle
Rationale: The pulmonary valve closes at the beginning of ventricular
diastole when the ventricular pressure drops below the arterial
pressure, preventing backflow into the ventricle.
,Question 5
When does the bicuspid (mitral) valve close?
A. When the left atrium contracts
B. When the left ventricle contracts
C. During ventricular diastole
D. When the aortic valve opens
Correct Answer: B. When the left ventricle contracts
Rationale: The mitral valve closes during left ventricular systole to
prevent blood from regurgitating back into the left atrium.
Question 6
When does the mitral valve open?
A. When ventricular pressure exceeds atrial pressure
B. During ventricular systole
C. When ventricular pressure drops below atrial pressure
D. When the semilunar valves close
Correct Answer: C. When ventricular pressure drops below atrial
pressure
Rationale: The mitral valve opens during diastole, allowing oxygenated
blood from the left atrium to fill the relaxed left ventricle.
Question 7
When do the semilunar valves open?
A. When atrial pressure exceeds ventricular pressure
B. When pressure in the ventricles exceeds pressure in the arteries
C. During ventricular diastole
D. When the AV valves are open
Correct Answer: B. When pressure in the ventricles exceeds
, pressure in the arteries
Rationale: This pressure gradient forces the aortic and pulmonary
valves open during the ejection phase of systole.
Question 8
When do the semilunar valves close?
A. During ventricular systole
B. When the atria contract
C. When pressure in the arteries is greater than pressure in the
ventricles
D. When the AV valves close
Correct Answer: C. When pressure in the arteries is greater than
pressure in the ventricles
Rationale: This occurs at the onset of diastole, preventing blood from
flowing back into the ventricles from the aorta and pulmonary trunk.
Question 9
What is the function of the pulmonary circuit?
A. Carries blood to the body tissues
B. Carries blood to the lungs for gas exchange and returns it to the
heart
C. Carries deoxygenated blood only
D. Carries oxygenated blood only
Correct Answer: B. Carries blood to the lungs for gas exchange
and returns it to the heart
Rationale: The pulmonary circuit is a low-pressure system that
oxygenates blood by exposing it to alveolar gas exchange.
