BIOS 255 Anatomy & Physiology III Exam 2 Review 100%
Correct & Verified Original Copy
Prepared for Exam Success
June 6, 2025
Multiple-Choice Questions
Question 1: Which hormone, secreted by the adrenal medulla, prepares the body for the "fight or
flight" response by increasing heart rate and blood glucose levels?
A. Cortisol
B. Aldosterone
C. Epinephrine
D. Norepinephrine
E. Both C and D
Answer: E
Rationale: Epinephrine and norepinephrine, both catecholamines, are released by the
adrenal medulla during stress. They increase heart rate, dilate bronchioles, and elevate
blood glucose by promoting glycogenolysis and gluconeogenesis, priming the body for
"fight or flight." Cortisol (A) is a glucocorticoid from the adrenal cortex, and aldosterone
(B) regulates sodium and water balance.
Question 2: What is the primary source of energy for cardiac muscle cells under normal physiological
conditions?
A. Glucose
B. Fatty acids
C. Amino acids
D. Ketone bodies
Answer: B
Rationale: Cardiac muscle preferentially uses fatty acids for energy via beta-oxidation,
as they provide a high yield of ATP to sustain constant contractions. Glucose (A) is a
secondary source, while amino acids (C) and ketone bodies (D) are utilized minimally
under normal conditions.
Question 3: Which structure in the nephron is primarily responsible for the reabsorption of glucose,
amino acids, and ions under normal conditions?
A. Glomerulus
B. Proximal convoluted tubule
C. Loop of Henle
D. Distal convoluted tubule
1
, Answer: B
Rationale: The proximal convoluted tubule reabsorbs approximately 65% of filtered
water, nearly all glucose and amino acids, and significant ions (e.g., Na+ , Cl− ) via active
and passive transport. The glomerulus (A) filters blood, while the loop of Henle (C) and
distal tubule (D) focus on concentration and fine-tuning.
Question 4: What effect does an increase in sympathetic nervous system activity have on the diameter
of coronary arteries?
A. Vasoconstriction
B. Vasodilation
C. No change
D. Initial vasoconstriction followed by vasodilation
Answer: B
Rationale: Sympathetic stimulation causes vasodilation of coronary arteries via beta-
adrenergic receptors, increasing blood flow to meet the heart’s elevated metabolic de-
mand during stress. Vasoconstriction (A) occurs in some vascular beds but not typically
in coronary arteries under sympathetic influence.
Question 5: Which of the following best describes the role of angiotensin II in the renin-angiotensin-
aldosterone system (RAAS)?
A. Stimulates vasodilation
B. Increases sodium reabsorption in the proximal tubule
C. Promotes vasoconstriction and aldosterone release
D. Inhibits antidiuretic hormone secretion
Answer: C
Rationale: Angiotensin II is a potent vasoconstrictor, raising blood pressure, and stim-
ulates the adrenal cortex to release aldosterone, which enhances sodium and water reab-
sorption in the distal nephron, increasing blood volume. It does not cause vasodilation
(A) or directly affect the proximal tubule (B).
Question 6: During ventricular systole, which valves are closed to prevent backflow into the atria?
A. Semilunar valves
B. Atrioventricular valves
C. Pulmonary valve only
D. Aortic valve only
Answer: B
Rationale: The atrioventricular valves (mitral and tricuspid) close during ventricular sys-
tole to prevent blood from flowing back into the atria as the ventricles contract. Semilunar
valves (A) open to allow blood into the aorta and pulmonary artery.
Question 7: What is the primary stimulus for the release of antidiuretic hormone (ADH) from the
posterior pituitary?
2
, A. Decreased blood osmolarity
B. Increased blood osmolarity
C. Increased blood volume
D. Decreased blood pressure
Answer: B
Rationale: Increased blood osmolarity, detected by hypothalamic osmoreceptors, trig-
gers ADH release to promote water reabsorption in the collecting duct, concentrating
urine and restoring osmolarity. Decreased osmolarity (A) inhibits ADH, while blood
volume and pressure (C, D) are secondary stimuli.
Question 8: Which component of the cardiac conduction system is known as the "pacemaker" of the
heart?
A. Atrioventricular node
B. Sinoatrial node
C. Bundle of His
D. Purkinje fibers
Answer: B
Rationale: The sinoatrial (SA) node, located in the right atrium, initiates the cardiac
cycle by generating electrical impulses, setting the heart’s rhythm. The AV node (A)
delays the signal, and the Bundle of His (C) and Purkinje fibers (D) conduct it to the
ventricles.
Question 9: In the respiratory system, what is the primary driving force for the movement of oxygen
into the bloodstream?
A. Active transport
B. Partial pressure gradient
C. Osmotic pressure
D. Facilitated diffusion
Answer: B
Rationale: Oxygen moves from the alveoli (high partial pressure) to the blood (lower
partial pressure) via simple diffusion driven by the partial pressure gradient. Active trans-
port (A) and osmotic pressure (C) are not involved, and facilitated diffusion (D) is less
dominant.
Question 10: What is the effect of hyperventilation on blood pH?
A. Decreases pH (acidosis)
B. Increases pH (alkalosis)
C. No change in pH
D. Depends on underlying cause
3
Correct & Verified Original Copy
Prepared for Exam Success
June 6, 2025
Multiple-Choice Questions
Question 1: Which hormone, secreted by the adrenal medulla, prepares the body for the "fight or
flight" response by increasing heart rate and blood glucose levels?
A. Cortisol
B. Aldosterone
C. Epinephrine
D. Norepinephrine
E. Both C and D
Answer: E
Rationale: Epinephrine and norepinephrine, both catecholamines, are released by the
adrenal medulla during stress. They increase heart rate, dilate bronchioles, and elevate
blood glucose by promoting glycogenolysis and gluconeogenesis, priming the body for
"fight or flight." Cortisol (A) is a glucocorticoid from the adrenal cortex, and aldosterone
(B) regulates sodium and water balance.
Question 2: What is the primary source of energy for cardiac muscle cells under normal physiological
conditions?
A. Glucose
B. Fatty acids
C. Amino acids
D. Ketone bodies
Answer: B
Rationale: Cardiac muscle preferentially uses fatty acids for energy via beta-oxidation,
as they provide a high yield of ATP to sustain constant contractions. Glucose (A) is a
secondary source, while amino acids (C) and ketone bodies (D) are utilized minimally
under normal conditions.
Question 3: Which structure in the nephron is primarily responsible for the reabsorption of glucose,
amino acids, and ions under normal conditions?
A. Glomerulus
B. Proximal convoluted tubule
C. Loop of Henle
D. Distal convoluted tubule
1
, Answer: B
Rationale: The proximal convoluted tubule reabsorbs approximately 65% of filtered
water, nearly all glucose and amino acids, and significant ions (e.g., Na+ , Cl− ) via active
and passive transport. The glomerulus (A) filters blood, while the loop of Henle (C) and
distal tubule (D) focus on concentration and fine-tuning.
Question 4: What effect does an increase in sympathetic nervous system activity have on the diameter
of coronary arteries?
A. Vasoconstriction
B. Vasodilation
C. No change
D. Initial vasoconstriction followed by vasodilation
Answer: B
Rationale: Sympathetic stimulation causes vasodilation of coronary arteries via beta-
adrenergic receptors, increasing blood flow to meet the heart’s elevated metabolic de-
mand during stress. Vasoconstriction (A) occurs in some vascular beds but not typically
in coronary arteries under sympathetic influence.
Question 5: Which of the following best describes the role of angiotensin II in the renin-angiotensin-
aldosterone system (RAAS)?
A. Stimulates vasodilation
B. Increases sodium reabsorption in the proximal tubule
C. Promotes vasoconstriction and aldosterone release
D. Inhibits antidiuretic hormone secretion
Answer: C
Rationale: Angiotensin II is a potent vasoconstrictor, raising blood pressure, and stim-
ulates the adrenal cortex to release aldosterone, which enhances sodium and water reab-
sorption in the distal nephron, increasing blood volume. It does not cause vasodilation
(A) or directly affect the proximal tubule (B).
Question 6: During ventricular systole, which valves are closed to prevent backflow into the atria?
A. Semilunar valves
B. Atrioventricular valves
C. Pulmonary valve only
D. Aortic valve only
Answer: B
Rationale: The atrioventricular valves (mitral and tricuspid) close during ventricular sys-
tole to prevent blood from flowing back into the atria as the ventricles contract. Semilunar
valves (A) open to allow blood into the aorta and pulmonary artery.
Question 7: What is the primary stimulus for the release of antidiuretic hormone (ADH) from the
posterior pituitary?
2
, A. Decreased blood osmolarity
B. Increased blood osmolarity
C. Increased blood volume
D. Decreased blood pressure
Answer: B
Rationale: Increased blood osmolarity, detected by hypothalamic osmoreceptors, trig-
gers ADH release to promote water reabsorption in the collecting duct, concentrating
urine and restoring osmolarity. Decreased osmolarity (A) inhibits ADH, while blood
volume and pressure (C, D) are secondary stimuli.
Question 8: Which component of the cardiac conduction system is known as the "pacemaker" of the
heart?
A. Atrioventricular node
B. Sinoatrial node
C. Bundle of His
D. Purkinje fibers
Answer: B
Rationale: The sinoatrial (SA) node, located in the right atrium, initiates the cardiac
cycle by generating electrical impulses, setting the heart’s rhythm. The AV node (A)
delays the signal, and the Bundle of His (C) and Purkinje fibers (D) conduct it to the
ventricles.
Question 9: In the respiratory system, what is the primary driving force for the movement of oxygen
into the bloodstream?
A. Active transport
B. Partial pressure gradient
C. Osmotic pressure
D. Facilitated diffusion
Answer: B
Rationale: Oxygen moves from the alveoli (high partial pressure) to the blood (lower
partial pressure) via simple diffusion driven by the partial pressure gradient. Active trans-
port (A) and osmotic pressure (C) are not involved, and facilitated diffusion (D) is less
dominant.
Question 10: What is the effect of hyperventilation on blood pH?
A. Decreases pH (acidosis)
B. Increases pH (alkalosis)
C. No change in pH
D. Depends on underlying cause
3
