BIOS 255 EDAPT Week 4: Cardiovascular and Respiratory Systems
2026 Chamberlain
1. Which layer of the blood vessel wall is responsible for vasoconstriction and
vasodilation?
A. Tunica media
B. Tunica externa
C. Tunica intima
D. Tunica adventitia
Answer: A
Rationale: The tunica media contains smooth muscle and elastic fibers that regulate the
diameter of the vessel lumen.
2. Which type of capillary is the most common and found in muscle and skin?
A. Fenestrated capillaries
B. Continuous capillaries
C. Sinusoid capillaries
D. Discontinuous capillaries
Answer: B
Rationale: Continuous capillaries are the most widespread, characterized by an
uninterrupted endothelial lining.
,3. Where are the cardiovascular centers that help regulate blood pressure
located?
A. Cerebrum
B. Medulla oblongata
C. Thalamus
D. Cerebellum
Answer: B
Rationale: The medulla oblongata contains the cardiac and vasomotor centers that control
heart rate and blood vessel diameter.
4. Which factor has the greatest influence on peripheral resistance in the blood
vessels?
A. Blood vessel radius
B. Total blood vessel length
C. Blood viscosity
D. Blood volume
Answer: A
Rationale: Resistance is inversely proportional to the fourth power of the vessel radius;
small changes in radius cause large changes in resistance.
5. What is the primary function of venous valves?
A. To increase blood pressure
B. To prevent the backflow of blood
C. To filter metabolic waste
D. To speed up heart rate
Answer: B
Rationale: Valves in veins, especially in the limbs, ensure that blood flows in one direction
toward the heart against gravity.
, 6. Which hormone is released by the atria of the heart to lower blood pressure?
A. Antidiuretic hormone (ADH)
B. Atrial Natriuretic Peptide (ANP)
C. Aldosterone
D. Angiotensin II
Answer: B
Rationale: ANP promotes salt and water excretion by the kidneys, which lowers blood
volume and blood pressure.
7. In which vessels is the velocity of blood flow the slowest?
A. Capillaries
B. Veins
C. Arteries
D. Arterioles
Answer: A
Rationale: Blood flow is slowest in capillaries to allow sufficient time for the exchange of
gases and nutrients between blood and tissues.
8. What formula is used to calculate Mean Arterial Pressure (MAP)?
A. Diastolic + 1/3 (Pulse Pressure)
B. Systolic + Diastolic
C. Systolic - Diastolic
D. 2x Systolic + Diastolic
Answer: A
Rationale: MAP is calculated as the diastolic pressure plus one-third of the pulse pressure
(the difference between systolic and diastolic).
2026 Chamberlain
1. Which layer of the blood vessel wall is responsible for vasoconstriction and
vasodilation?
A. Tunica media
B. Tunica externa
C. Tunica intima
D. Tunica adventitia
Answer: A
Rationale: The tunica media contains smooth muscle and elastic fibers that regulate the
diameter of the vessel lumen.
2. Which type of capillary is the most common and found in muscle and skin?
A. Fenestrated capillaries
B. Continuous capillaries
C. Sinusoid capillaries
D. Discontinuous capillaries
Answer: B
Rationale: Continuous capillaries are the most widespread, characterized by an
uninterrupted endothelial lining.
,3. Where are the cardiovascular centers that help regulate blood pressure
located?
A. Cerebrum
B. Medulla oblongata
C. Thalamus
D. Cerebellum
Answer: B
Rationale: The medulla oblongata contains the cardiac and vasomotor centers that control
heart rate and blood vessel diameter.
4. Which factor has the greatest influence on peripheral resistance in the blood
vessels?
A. Blood vessel radius
B. Total blood vessel length
C. Blood viscosity
D. Blood volume
Answer: A
Rationale: Resistance is inversely proportional to the fourth power of the vessel radius;
small changes in radius cause large changes in resistance.
5. What is the primary function of venous valves?
A. To increase blood pressure
B. To prevent the backflow of blood
C. To filter metabolic waste
D. To speed up heart rate
Answer: B
Rationale: Valves in veins, especially in the limbs, ensure that blood flows in one direction
toward the heart against gravity.
, 6. Which hormone is released by the atria of the heart to lower blood pressure?
A. Antidiuretic hormone (ADH)
B. Atrial Natriuretic Peptide (ANP)
C. Aldosterone
D. Angiotensin II
Answer: B
Rationale: ANP promotes salt and water excretion by the kidneys, which lowers blood
volume and blood pressure.
7. In which vessels is the velocity of blood flow the slowest?
A. Capillaries
B. Veins
C. Arteries
D. Arterioles
Answer: A
Rationale: Blood flow is slowest in capillaries to allow sufficient time for the exchange of
gases and nutrients between blood and tissues.
8. What formula is used to calculate Mean Arterial Pressure (MAP)?
A. Diastolic + 1/3 (Pulse Pressure)
B. Systolic + Diastolic
C. Systolic - Diastolic
D. 2x Systolic + Diastolic
Answer: A
Rationale: MAP is calculated as the diastolic pressure plus one-third of the pulse pressure
(the difference between systolic and diastolic).
