BIOL 252 Human Anatomy & Physiology
II w/Lab | Module 3 Exam Review
Section 1: Blood Vessel Structure & Function (Questions 1–30)
Question 1
Which layer of a blood vessel wall contains smooth muscle cells that regulate
lumen diameter?
A. Tunica intima
B. Tunica media
C. Tunica externa
D. Basement membrane
Correct Answer: B
Explanation: The tunica media contains circularly arranged smooth muscle;
contraction causes vasoconstriction and relaxation causes vasodilation, controlled
primarily by sympathetic fibers.
Question 2
A patient with a thoracic aortic aneurysm undergoes imaging that reveals
significant stretching of the vessel wall with each ventricular contraction. Which
structural component is most responsible for this normal elastic behavior?
A. Collagen fibers in the tunica externa
B. Smooth muscle in the tunica media
C. Elastin fibers in the tunica media
D. Endothelial tight junctions
Correct Answer: C
,Explanation: Elastic arteries contain abundant elastin in the tunica media,
allowing them to stretch during systole and recoil during diastole to maintain
continuous blood flow.
Question 3
Which vessel type possesses valves that prevent backflow of blood?
A. Elastic arteries
B. Muscular arteries
C. Arterioles
D. Medium veins
Correct Answer: D
Explanation: Medium veins contain intimal folds forming valves; these are
essential because venous pressure is too low to oppose gravity without them,
especially in the lower limbs.
Question 4
A histology slide shows a vessel with a thin tunica media, a large lumen, and an
absent internal elastic lamina. This vessel is most likely a:
A. Muscular artery
B. Elastic artery
C. Vein
D. Arteriole
Correct Answer: C
Explanation: Veins lack internal and external elastic laminae, have little smooth
muscle, and possess large lumens to serve as low-pressure capacitance vessels.
Question 5
What is the primary function of precapillary sphincters?
,A. To regulate blood flow into capillary beds
B. To prevent backflow into arterioles
C. To increase blood velocity in venules
D. To filter plasma proteins
Correct Answer: A
Explanation: Precapillary sphincters are rings of smooth muscle at capillary
entrances; their contraction or relaxation adjusts perfusion to match local tissue
metabolic needs.
Question 6
Which vessel type has the greatest total cross-sectional area in the systemic
circulation?
A. Aorta
B. Arterioles
C. Capillaries
D. Venae cavae
Correct Answer: C
Explanation: Although individual capillaries are microscopic, their enormous
collective cross-sectional area slows blood velocity to facilitate exchange; velocity
is inversely proportional to total area.
Question 7
A patient with liver cirrhosis develops portal hypertension. Which vessel type is
most directly affected by the increased resistance to portal flow?
A. Hepatic artery
B. Hepatic portal vein
C. Central artery of the spleen
D. Renal artery
, Correct Answer: B
Explanation: The hepatic portal vein carries nutrient-rich blood from the GI tract
to liver sinusoids; cirrhosis increases intrahepatic resistance, causing portal
hypertension and collateral formation.
Question 8
Which structure allows capillaries to exchange materials with minimal diffusion
distance?
A. Thick tunica media
B. Single layer of endothelial cells and basement membrane
C. Elastic laminae
D. Smooth muscle sphincters
Correct Answer: B
Explanation: Capillary walls consist of one endothelial cell layer plus basement
membrane; this minimizes diffusion distance for gases, nutrients, and wastes
between blood and tissues.
Question 9
Anastomoses between arteries supplying the same region provide which
functional advantage?
A. Increased blood pressure
B. Collateral circulation if one vessel is blocked
C. Slower blood flow
D. Reduced capillary density
Correct Answer: B
Explanation: Arterial anastomoses create alternate routes; collateral channels can
perfuse tissue when a primary artery is occluded, reducing ischemic damage in
organs like the brain and heart.
II w/Lab | Module 3 Exam Review
Section 1: Blood Vessel Structure & Function (Questions 1–30)
Question 1
Which layer of a blood vessel wall contains smooth muscle cells that regulate
lumen diameter?
A. Tunica intima
B. Tunica media
C. Tunica externa
D. Basement membrane
Correct Answer: B
Explanation: The tunica media contains circularly arranged smooth muscle;
contraction causes vasoconstriction and relaxation causes vasodilation, controlled
primarily by sympathetic fibers.
Question 2
A patient with a thoracic aortic aneurysm undergoes imaging that reveals
significant stretching of the vessel wall with each ventricular contraction. Which
structural component is most responsible for this normal elastic behavior?
A. Collagen fibers in the tunica externa
B. Smooth muscle in the tunica media
C. Elastin fibers in the tunica media
D. Endothelial tight junctions
Correct Answer: C
,Explanation: Elastic arteries contain abundant elastin in the tunica media,
allowing them to stretch during systole and recoil during diastole to maintain
continuous blood flow.
Question 3
Which vessel type possesses valves that prevent backflow of blood?
A. Elastic arteries
B. Muscular arteries
C. Arterioles
D. Medium veins
Correct Answer: D
Explanation: Medium veins contain intimal folds forming valves; these are
essential because venous pressure is too low to oppose gravity without them,
especially in the lower limbs.
Question 4
A histology slide shows a vessel with a thin tunica media, a large lumen, and an
absent internal elastic lamina. This vessel is most likely a:
A. Muscular artery
B. Elastic artery
C. Vein
D. Arteriole
Correct Answer: C
Explanation: Veins lack internal and external elastic laminae, have little smooth
muscle, and possess large lumens to serve as low-pressure capacitance vessels.
Question 5
What is the primary function of precapillary sphincters?
,A. To regulate blood flow into capillary beds
B. To prevent backflow into arterioles
C. To increase blood velocity in venules
D. To filter plasma proteins
Correct Answer: A
Explanation: Precapillary sphincters are rings of smooth muscle at capillary
entrances; their contraction or relaxation adjusts perfusion to match local tissue
metabolic needs.
Question 6
Which vessel type has the greatest total cross-sectional area in the systemic
circulation?
A. Aorta
B. Arterioles
C. Capillaries
D. Venae cavae
Correct Answer: C
Explanation: Although individual capillaries are microscopic, their enormous
collective cross-sectional area slows blood velocity to facilitate exchange; velocity
is inversely proportional to total area.
Question 7
A patient with liver cirrhosis develops portal hypertension. Which vessel type is
most directly affected by the increased resistance to portal flow?
A. Hepatic artery
B. Hepatic portal vein
C. Central artery of the spleen
D. Renal artery
, Correct Answer: B
Explanation: The hepatic portal vein carries nutrient-rich blood from the GI tract
to liver sinusoids; cirrhosis increases intrahepatic resistance, causing portal
hypertension and collateral formation.
Question 8
Which structure allows capillaries to exchange materials with minimal diffusion
distance?
A. Thick tunica media
B. Single layer of endothelial cells and basement membrane
C. Elastic laminae
D. Smooth muscle sphincters
Correct Answer: B
Explanation: Capillary walls consist of one endothelial cell layer plus basement
membrane; this minimizes diffusion distance for gases, nutrients, and wastes
between blood and tissues.
Question 9
Anastomoses between arteries supplying the same region provide which
functional advantage?
A. Increased blood pressure
B. Collateral circulation if one vessel is blocked
C. Slower blood flow
D. Reduced capillary density
Correct Answer: B
Explanation: Arterial anastomoses create alternate routes; collateral channels can
perfuse tissue when a primary artery is occluded, reducing ischemic damage in
organs like the brain and heart.
