Question 1

Why would it be advantageous for a reptile basking in the sun to mix oxygenated and deoxygenated blood in its heart?

Accepted Answer

A)  Because it is able to absorb oxygen through the skin 
B)  Because its heart is a result of incomplete evolution 
C)  When basking, the reptile has a minimal oxygen requirement 
D)  Because it has only vestigial lungs 
E)  Because its pulmonary circulation produces small amounts of oxygen as a by-product of pigmentation reaction with photons from the sun 
A)  Because it is able to absorb oxygen through the skin 
B)  Because its heart is a result of incomplete evolution 
C)  When basking, the reptile has a minimal oxygen requirement 
D)  Because it has only vestigial lungs 
E)  Because its pulmonary circulation produces small amounts of oxygen as a by-product of pigmentation reaction with photons from the sun

Question 2

In mammalian hearts, the wall of the left ventricle is thicker than that of the right ventricle because

Accepted Answer

A)  systemic pressure is greater than pulmonary pressure. 
B)  the left ventricle pumps a greater volume of blood than the right ventricle. 
C)  contractions of the left ventricle fill more arteries than contractions of the right ventricle. 
D)  blood loses pressure as it passes through the lungs. 
E)  it arose from a larger aortic arch during evolution. 
A)  systemic pressure is greater than pulmonary pressure. 
B)  the left ventricle pumps a greater volume of blood than the right ventricle. 
C)  contractions of the left ventricle fill more arteries than contractions of the right ventricle. 
D)  blood loses pressure as it passes through the lungs. 
E)  it arose from a larger aortic arch during evolution.

Question 3

At the site of damage to a blood vessel, thrombin

Accepted Answer

A)  causes the traumatised vessel to contract. 
B)  stimulates platelets to release fibrin. 
C)  causes platelets to break down. 
D)  binds to platelets to form a clot. 
E)  converts fibrinogen into insoluble fibrin. 
A)  causes the traumatised vessel to contract. 
B)  stimulates platelets to release fibrin. 
C)  causes platelets to break down. 
D)  binds to platelets to form a clot. 
E)  converts fibrinogen into insoluble fibrin.

Question 4

When blood enters a mammalian heart, it flows through several valves in a distinct pattern. What is the order in which blood flows through these valves?

Accepted Answer

A)  Aortic semilunar valve, pulmonary semilunar valve, tricuspid valve, mitral valve 
B)  Pulmonary semilunar valve, mitral valve, tricuspid valve, aortic semilunar valve 
C)  Tricuspid valve, pulmonary semilunar valve, aortic semilunar valve, mitral valve 
D)  Tricuspid valve, pulmonary semilunar valve, mitral valve, aortic semilunar valve 
E)  Mitral valve, aortic semilunar valve, tricuspid valve, pulmonary semilunar valve 
A)  Aortic semilunar valve, pulmonary semilunar valve, tricuspid valve, mitral valve 
B)  Pulmonary semilunar valve, mitral valve, tricuspid valve, aortic semilunar valve 
C)  Tricuspid valve, pulmonary semilunar valve, aortic semilunar valve, mitral valve 
D)  Tricuspid valve, pulmonary semilunar valve, mitral valve, aortic semilunar valve 
E)  Mitral valve, aortic semilunar valve, tricuspid valve, pulmonary semilunar valve

Question 5

So that blood flow to individual organs in the mammalian circulatory system can be altered without appreciably affecting blood flow to other organs

Accepted Answer

A)  the arteries supply the major organs in parallel rather than in series. 
B)  the heartbeat generates relatively high arterial blood pressure. 
C)  negative feedback systems make compensatory changes to peripheral resistance throughout the circulatory system. 
D)  baroreceptors detect and respond to changes in blood pressure. 
E)  All of the answers are correct. 
A)  the arteries supply the major organs in parallel rather than in series. 
B)  the heartbeat generates relatively high arterial blood pressure. 
C)  negative feedback systems make compensatory changes to peripheral resistance throughout the circulatory system. 
D)  baroreceptors detect and respond to changes in blood pressure. 
E)  All of the answers are correct.

Exam 24: Circulation

Why would it be advantageous for a reptile basking in the sun to mix oxygenated and deoxygenated blood in its heart?

In mammalian hearts, the wall of the left ventricle is thicker than that of the right ventricle because

At the site of damage to a blood vessel, thrombin

When blood enters a mammalian heart, it flows through several valves in a distinct pattern. What is the order in which blood flows through these valves?

So that blood flow to individual organs in the mammalian circulatory system can be altered without appreciably affecting blood flow to other organs

Nature of Molecules

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