IVY TECH APHY 101 FINAL EXAM | 2025/2026
LATEST EDITION | | REAL EXAM QUESTIONS
AND VERIFIED ANSWERS | 100% ACCURACY |
ANATOMY & PHYSIOLOGY I | GRADED A+
1. A transmembrane protein has a domain that spans the lipid bilayer and contains several
hydrophobic amino acids. Which of the following best describes the primary force driving the
folding of this domain into an alpha-helix as it inserts into the membrane?
A. Hydrogen bonding between polar side chains and water molecules in the cytosol
B. Van der Waals interactions between hydrophobic side chains and the lipid tails
C. Ionic bonding between charged residues and phospholipid head groups
D. Disulfide bridge formation between cysteine residues within the helix
Answer: B
Rationale: The hydrophobic effect drives the insertion of transmembrane domains: hydrophobic side
chains minimize contact with water by associating with the hydrophobic lipid tails via van der Waals
interactions. Hydrogen bonding (A) is important for helix stability but not for membrane insertion. Ionic
bonds (C) are unlikely in the hydrophobic core. Disulfide bridges (D) are not involved in membrane
insertion.
2. During skeletal muscle contraction, the power stroke occurs when the myosin head pivots,
pulling the actin filament toward the M-line. Which of the following events directly triggers the
power stroke?
A. Release of inorganic phosphate (Pi) from the myosin head after ATP hydrolysis
B. Binding of ATP to the myosin head, causing its release from actin
C. Calcium binding to troponin, exposing the myosin-binding sites on actin
D. Hydrolysis of ATP by the myosin head, providing energy for the power stroke
Answer: A
Rationale: The power stroke is directly triggered by the release of Pi from the myosin-ADP-Pi complex,
which strengthens actin binding and causes the myosin head to pivot. ATP binding (B) causes myosin to
detach from actin. Calcium binding (C) is a prerequisite but not the trigger. ATP hydrolysis (D) provides
energy for the cocking of the myosin head, not for the power stroke.
3. Which of the following best explains why the resting membrane potential of a neuron is close to
the equilibrium potential for potassium (E_K)?
A. The plasma membrane is impermeable to sodium ions at rest.
B. The Na+/K+ ATPase pumps three Na+ out for every two K+ in, creating a net negative charge inside.
Page 1
,C. The membrane has a much higher permeability to K+ than to Na+ at rest, and K+ diffuses out until the
electrical gradient opposes further net movement.
D. Chloride ions diffuse into the cell, balancing the positive charge from sodium leak channels.
Answer: C
Rationale: At rest, the membrane is highly permeable to K+ due to leak channels, allowing K+ to move
down its concentration gradient until the electrical gradient opposes further net flux, bringing the
membrane potential close to E_K (~ -90 mV). Option A is false: there is some Na+ permeability. Option
B describes the pump's electrogenic effect but that contributes only a few mV. Option D is incorrect; Cl-
distribution is passive and near equilibrium.
4. A researcher observes that a particular chemical messenger binds to a G-protein-coupled
receptor (GPCR) on a smooth muscle cell, leading to relaxation. Which intracellular signaling
cascade is most likely responsible?
A. Activation of phospholipase C, production of IP3, and release of Ca2+ from the sarcoplasmic reticulum
B. Activation of adenylyl cyclase, increase in cAMP, and activation of protein kinase A, which phosphorylates
myosin light chain kinase (MLCK), reducing its activity
C. Activation of guanylyl cyclase, increase in cGMP, and activation of protein kinase G, which phosphorylates
and opens K+ channels
D. Direct opening of voltage-gated calcium channels, causing Ca2+ influx and activation of calmodulin
Answer: B
Rationale: In smooth muscle, relaxation often occurs via ²2-adrenergic receptors (GPCRs) that stimulate
adenylyl cyclase, increasing cAMP. PKA then phosphorylates MLCK, decreasing its affinity for
Ca2+-calmodulin, thus reducing myosin light chain phosphorylation and promoting relaxation. Option
A (IP3/Ca2+) would cause contraction. Option C (cGMP) mediates relaxation in some vessels but is less
common for GPCRs. Option D would cause contraction.
5. A patient presents with a fracture of the proximal femur. Which of the following arteries is most
likely to be compromised, leading to avascular necrosis of the femoral head?
A. Lateral circumflex femoral artery
B. Medial circumflex femoral artery
C. Obturator artery
D. Superior gluteal artery
Answer: B
Rationale: The medial circumflex femoral artery gives rise to the lateral epiphyseal arteries, which
supply the femoral head. Fracture of the femoral neck can disrupt these vessels, leading to avascular
necrosis. The lateral circumflex (A) supplies the femoral neck but not the head. The obturator artery (C)
supplies the hip joint via the acetabular branch but is not the main supply to the femoral head. The
superior gluteal artery (D) supplies the gluteal region.
6. Which of the following correctly describes the relationship between the length-tension curve of a
sarcomere and the sliding filament theory?
A. Maximum tension is generated when the sarcomere is at its shortest length because actin and myosin overlap
the most.
Page 2
,B. Tension is lowest at intermediate sarcomere lengths because cross-bridge formation is optimal.
C. Maximum tension occurs when the sarcomere length allows optimal overlap of thick and thin filaments, so that all
myosin heads can bind to actin.
D. Tension increases linearly as sarcomere length increases because more cross-bridges can form.
Answer: C
Rationale: The length-tension relationship shows that maximum tension is produced at optimal
sarcomere length (about 2.2 m) where there is maximal overlap of thick and thin filaments, allowing the
greatest number of cross-bridges. At shorter lengths (A), filaments overlap too much, reducing tension.
At longer lengths (D), overlap decreases, reducing tension. Option B is false: intermediate lengths give
optimal tension.
7. A patient has a tumor that compresses the left recurrent laryngeal nerve. Which of the following
symptoms would you expect?
A. Loss of taste sensation on the posterior third of the tongue
B. Hoarseness and difficulty speaking due to paralysis of the left vocal cord
C. Difficulty swallowing due to impaired pharyngeal constriction
D. Loss of sensation over the laryngeal mucosa above the vocal folds
Answer: B
Rationale: The recurrent laryngeal nerve (a branch of the vagus nerve) innervates all intrinsic laryngeal
muscles except the cricothyroid. Compression leads to vocal cord paralysis, causing hoarseness. Option
A is related to the glossopharyngeal nerve. Option C involves the pharyngeal plexus. Option D involves
the internal laryngeal nerve (superior laryngeal nerve), not the recurrent laryngeal.
8. Which of the following best explains why the partial pressure of oxygen (PO2) in systemic
arterial blood is lower than the PO2 in alveolar air (about 100 mmHg vs. 104 mmHg)?
A. Oxygen is consumed by the pulmonary capillary endothelial cells during transit.
B. There is a small amount of venous admixture (physiological shunt) from bronchial and thebesian veins.
C. Oxygen diffuses more slowly across the respiratory membrane than carbon dioxide.
D. The alveolar ventilation-perfusion ratio is exactly 1, causing incomplete equilibration.
Answer: B
Rationale: The normal A-a gradient (about 4 mmHg) is primarily due to venous admixture: deoxygenated
blood from bronchial veins (draining the lungs) and thebesian veins (draining the heart) bypasses
alveolar gas exchange and mixes with oxygenated blood, slightly lowering arterial PO2. Option A is
false; oxygen consumption by endothelial cells is negligible. Option C is false; O2 diffuses less rapidly
than CO2 but still equilibrates. Option D is incorrect; V/Q mismatch can increase the gradient, but at
exactly 1, equilibration is complete.
9. A patient with chronic kidney disease develops metabolic acidosis. Which of the following renal
compensatory mechanisms would be most expected?
A. Increased reabsorption of filtered bicarbonate in the proximal tubule
B. Increased secretion of H+ in the collecting duct, with increased excretion of ammonium (NH4+) and
titratable acids
C. Decreased production of ammonia in the proximal tubule to conserve glutamine
Page 3
, D. Increased excretion of bicarbonate in the urine to raise blood pH
Answer: B
Rationale: In metabolic acidosis, the kidneys compensate by increasing H+ secretion (mainly in the
collecting duct) and enhancing ammonia production (from glutamine) to buffer H+ as NH4+, and by
excreting more titratable acids (e.g., phosphate). Option A (increased bicarbonate reabsorption) occurs
but is not the primary compensatory mechanism; it helps conserve bicarbonate. Option C is opposite;
ammonia production increases. Option D would worsen acidosis.
10. Which of the following statements best describes the role of the hypothalamic-pituitary-adrenal
(HPA) axis in the body's response to stress?
A. Corticotropin-releasing hormone (CRH) from the hypothalamus stimulates the posterior pituitary to release
adrenocorticotropic hormone (ACTH), which acts on the adrenal medulla to release epinephrine.
B. Adrenocorticotropic hormone (ACTH) from the anterior pituitary stimulates the adrenal cortex to release
cortisol, which increases blood glucose and suppresses the immune system.
C. Cortisol exerts negative feedback on the hypothalamus and anterior pituitary, inhibiting CRH and ACTH
release, but also stimulates the adrenal medulla to secrete norepinephrine.
D. The HPA axis is activated by the sympathetic nervous system, leading to rapid release of cortisol from the
adrenal medulla.
Answer: B
Rationale: The HPA axis: Hypothalamus releases CRH !’ anterior pituitary releases ACTH !’ adrenal
cortex secretes cortisol. Cortisol raises blood glucose (gluconeogenesis) and suppresses immune
function. Option A is wrong: posterior pituitary does not release ACTH; ACTH is from anterior
pituitary. Option C is wrong: cortisol inhibits CRH/ACTH but does not stimulate adrenal medulla.
Option D is wrong: cortisol is from adrenal cortex, not medulla; the HPA axis is slower than the
sympathetic response.
11. During an action potential in a ventricular cardiomyocyte, which of the following correctly
describes the ionic basis for the plateau phase (phase 2)?
A. Rapid influx of Na+ through voltage-gated Na+ channels, balanced by efflux of K+ through delayed rectifier
K+ channels.
B. Sustained influx of Ca2+ through L-type Ca2+ channels, balanced by efflux of K+ through delayed rectifier
K+ channels.
C. Influx of Ca2+ through T-type Ca2+ channels, with no significant K+ efflux.
D. Efflux of K+ through inward rectifier K+ channels, with no counterbalancing inward current.
Answer: B
Rationale: The plateau phase (phase 2) of the cardiac action potential is maintained by the sustained
influx of Ca2+ through L-type Ca2+ channels, which is balanced by the efflux of K+ through delayed
rectifier K+ channels. Option A describes phase 0 (rapid depolarization). Option C is incorrect because
T-type Ca2+ channels contribute to early depolarization, not the plateau. Option D would lead to
repolarization, not a plateau.
12. Which of the following best explains why the glomerular filtration rate (GFR) remains
relatively constant despite fluctuations in mean arterial pressure between 80 and 180 mmHg?
Page 4
LATEST EDITION | | REAL EXAM QUESTIONS
AND VERIFIED ANSWERS | 100% ACCURACY |
ANATOMY & PHYSIOLOGY I | GRADED A+
1. A transmembrane protein has a domain that spans the lipid bilayer and contains several
hydrophobic amino acids. Which of the following best describes the primary force driving the
folding of this domain into an alpha-helix as it inserts into the membrane?
A. Hydrogen bonding between polar side chains and water molecules in the cytosol
B. Van der Waals interactions between hydrophobic side chains and the lipid tails
C. Ionic bonding between charged residues and phospholipid head groups
D. Disulfide bridge formation between cysteine residues within the helix
Answer: B
Rationale: The hydrophobic effect drives the insertion of transmembrane domains: hydrophobic side
chains minimize contact with water by associating with the hydrophobic lipid tails via van der Waals
interactions. Hydrogen bonding (A) is important for helix stability but not for membrane insertion. Ionic
bonds (C) are unlikely in the hydrophobic core. Disulfide bridges (D) are not involved in membrane
insertion.
2. During skeletal muscle contraction, the power stroke occurs when the myosin head pivots,
pulling the actin filament toward the M-line. Which of the following events directly triggers the
power stroke?
A. Release of inorganic phosphate (Pi) from the myosin head after ATP hydrolysis
B. Binding of ATP to the myosin head, causing its release from actin
C. Calcium binding to troponin, exposing the myosin-binding sites on actin
D. Hydrolysis of ATP by the myosin head, providing energy for the power stroke
Answer: A
Rationale: The power stroke is directly triggered by the release of Pi from the myosin-ADP-Pi complex,
which strengthens actin binding and causes the myosin head to pivot. ATP binding (B) causes myosin to
detach from actin. Calcium binding (C) is a prerequisite but not the trigger. ATP hydrolysis (D) provides
energy for the cocking of the myosin head, not for the power stroke.
3. Which of the following best explains why the resting membrane potential of a neuron is close to
the equilibrium potential for potassium (E_K)?
A. The plasma membrane is impermeable to sodium ions at rest.
B. The Na+/K+ ATPase pumps three Na+ out for every two K+ in, creating a net negative charge inside.
Page 1
,C. The membrane has a much higher permeability to K+ than to Na+ at rest, and K+ diffuses out until the
electrical gradient opposes further net movement.
D. Chloride ions diffuse into the cell, balancing the positive charge from sodium leak channels.
Answer: C
Rationale: At rest, the membrane is highly permeable to K+ due to leak channels, allowing K+ to move
down its concentration gradient until the electrical gradient opposes further net flux, bringing the
membrane potential close to E_K (~ -90 mV). Option A is false: there is some Na+ permeability. Option
B describes the pump's electrogenic effect but that contributes only a few mV. Option D is incorrect; Cl-
distribution is passive and near equilibrium.
4. A researcher observes that a particular chemical messenger binds to a G-protein-coupled
receptor (GPCR) on a smooth muscle cell, leading to relaxation. Which intracellular signaling
cascade is most likely responsible?
A. Activation of phospholipase C, production of IP3, and release of Ca2+ from the sarcoplasmic reticulum
B. Activation of adenylyl cyclase, increase in cAMP, and activation of protein kinase A, which phosphorylates
myosin light chain kinase (MLCK), reducing its activity
C. Activation of guanylyl cyclase, increase in cGMP, and activation of protein kinase G, which phosphorylates
and opens K+ channels
D. Direct opening of voltage-gated calcium channels, causing Ca2+ influx and activation of calmodulin
Answer: B
Rationale: In smooth muscle, relaxation often occurs via ²2-adrenergic receptors (GPCRs) that stimulate
adenylyl cyclase, increasing cAMP. PKA then phosphorylates MLCK, decreasing its affinity for
Ca2+-calmodulin, thus reducing myosin light chain phosphorylation and promoting relaxation. Option
A (IP3/Ca2+) would cause contraction. Option C (cGMP) mediates relaxation in some vessels but is less
common for GPCRs. Option D would cause contraction.
5. A patient presents with a fracture of the proximal femur. Which of the following arteries is most
likely to be compromised, leading to avascular necrosis of the femoral head?
A. Lateral circumflex femoral artery
B. Medial circumflex femoral artery
C. Obturator artery
D. Superior gluteal artery
Answer: B
Rationale: The medial circumflex femoral artery gives rise to the lateral epiphyseal arteries, which
supply the femoral head. Fracture of the femoral neck can disrupt these vessels, leading to avascular
necrosis. The lateral circumflex (A) supplies the femoral neck but not the head. The obturator artery (C)
supplies the hip joint via the acetabular branch but is not the main supply to the femoral head. The
superior gluteal artery (D) supplies the gluteal region.
6. Which of the following correctly describes the relationship between the length-tension curve of a
sarcomere and the sliding filament theory?
A. Maximum tension is generated when the sarcomere is at its shortest length because actin and myosin overlap
the most.
Page 2
,B. Tension is lowest at intermediate sarcomere lengths because cross-bridge formation is optimal.
C. Maximum tension occurs when the sarcomere length allows optimal overlap of thick and thin filaments, so that all
myosin heads can bind to actin.
D. Tension increases linearly as sarcomere length increases because more cross-bridges can form.
Answer: C
Rationale: The length-tension relationship shows that maximum tension is produced at optimal
sarcomere length (about 2.2 m) where there is maximal overlap of thick and thin filaments, allowing the
greatest number of cross-bridges. At shorter lengths (A), filaments overlap too much, reducing tension.
At longer lengths (D), overlap decreases, reducing tension. Option B is false: intermediate lengths give
optimal tension.
7. A patient has a tumor that compresses the left recurrent laryngeal nerve. Which of the following
symptoms would you expect?
A. Loss of taste sensation on the posterior third of the tongue
B. Hoarseness and difficulty speaking due to paralysis of the left vocal cord
C. Difficulty swallowing due to impaired pharyngeal constriction
D. Loss of sensation over the laryngeal mucosa above the vocal folds
Answer: B
Rationale: The recurrent laryngeal nerve (a branch of the vagus nerve) innervates all intrinsic laryngeal
muscles except the cricothyroid. Compression leads to vocal cord paralysis, causing hoarseness. Option
A is related to the glossopharyngeal nerve. Option C involves the pharyngeal plexus. Option D involves
the internal laryngeal nerve (superior laryngeal nerve), not the recurrent laryngeal.
8. Which of the following best explains why the partial pressure of oxygen (PO2) in systemic
arterial blood is lower than the PO2 in alveolar air (about 100 mmHg vs. 104 mmHg)?
A. Oxygen is consumed by the pulmonary capillary endothelial cells during transit.
B. There is a small amount of venous admixture (physiological shunt) from bronchial and thebesian veins.
C. Oxygen diffuses more slowly across the respiratory membrane than carbon dioxide.
D. The alveolar ventilation-perfusion ratio is exactly 1, causing incomplete equilibration.
Answer: B
Rationale: The normal A-a gradient (about 4 mmHg) is primarily due to venous admixture: deoxygenated
blood from bronchial veins (draining the lungs) and thebesian veins (draining the heart) bypasses
alveolar gas exchange and mixes with oxygenated blood, slightly lowering arterial PO2. Option A is
false; oxygen consumption by endothelial cells is negligible. Option C is false; O2 diffuses less rapidly
than CO2 but still equilibrates. Option D is incorrect; V/Q mismatch can increase the gradient, but at
exactly 1, equilibration is complete.
9. A patient with chronic kidney disease develops metabolic acidosis. Which of the following renal
compensatory mechanisms would be most expected?
A. Increased reabsorption of filtered bicarbonate in the proximal tubule
B. Increased secretion of H+ in the collecting duct, with increased excretion of ammonium (NH4+) and
titratable acids
C. Decreased production of ammonia in the proximal tubule to conserve glutamine
Page 3
, D. Increased excretion of bicarbonate in the urine to raise blood pH
Answer: B
Rationale: In metabolic acidosis, the kidneys compensate by increasing H+ secretion (mainly in the
collecting duct) and enhancing ammonia production (from glutamine) to buffer H+ as NH4+, and by
excreting more titratable acids (e.g., phosphate). Option A (increased bicarbonate reabsorption) occurs
but is not the primary compensatory mechanism; it helps conserve bicarbonate. Option C is opposite;
ammonia production increases. Option D would worsen acidosis.
10. Which of the following statements best describes the role of the hypothalamic-pituitary-adrenal
(HPA) axis in the body's response to stress?
A. Corticotropin-releasing hormone (CRH) from the hypothalamus stimulates the posterior pituitary to release
adrenocorticotropic hormone (ACTH), which acts on the adrenal medulla to release epinephrine.
B. Adrenocorticotropic hormone (ACTH) from the anterior pituitary stimulates the adrenal cortex to release
cortisol, which increases blood glucose and suppresses the immune system.
C. Cortisol exerts negative feedback on the hypothalamus and anterior pituitary, inhibiting CRH and ACTH
release, but also stimulates the adrenal medulla to secrete norepinephrine.
D. The HPA axis is activated by the sympathetic nervous system, leading to rapid release of cortisol from the
adrenal medulla.
Answer: B
Rationale: The HPA axis: Hypothalamus releases CRH !’ anterior pituitary releases ACTH !’ adrenal
cortex secretes cortisol. Cortisol raises blood glucose (gluconeogenesis) and suppresses immune
function. Option A is wrong: posterior pituitary does not release ACTH; ACTH is from anterior
pituitary. Option C is wrong: cortisol inhibits CRH/ACTH but does not stimulate adrenal medulla.
Option D is wrong: cortisol is from adrenal cortex, not medulla; the HPA axis is slower than the
sympathetic response.
11. During an action potential in a ventricular cardiomyocyte, which of the following correctly
describes the ionic basis for the plateau phase (phase 2)?
A. Rapid influx of Na+ through voltage-gated Na+ channels, balanced by efflux of K+ through delayed rectifier
K+ channels.
B. Sustained influx of Ca2+ through L-type Ca2+ channels, balanced by efflux of K+ through delayed rectifier
K+ channels.
C. Influx of Ca2+ through T-type Ca2+ channels, with no significant K+ efflux.
D. Efflux of K+ through inward rectifier K+ channels, with no counterbalancing inward current.
Answer: B
Rationale: The plateau phase (phase 2) of the cardiac action potential is maintained by the sustained
influx of Ca2+ through L-type Ca2+ channels, which is balanced by the efflux of K+ through delayed
rectifier K+ channels. Option A describes phase 0 (rapid depolarization). Option C is incorrect because
T-type Ca2+ channels contribute to early depolarization, not the plateau. Option D would lead to
repolarization, not a plateau.
12. Which of the following best explains why the glomerular filtration rate (GFR) remains
relatively constant despite fluctuations in mean arterial pressure between 80 and 180 mmHg?
Page 4
