APHY 101 MIDTERM EXAM LATEST QUESTIONS AND
CORRECT ANSWERS IVY TECH COMMUNITY COLLEGE
INDIANAPOLIS
APHY 101 – 200 QUESTIONS Midterm Exam: 0 Most Tested & Difficult Questions
1. Question:
The sarcoplasmic reticulum (SR) in skeletal muscle fibers plays a critical role during muscle contraction.
Describe the sequence of events from the arrival of an action potential at the neuromuscular junction to
the contraction of the sarcomere, and explain how calcium ions regulate the interaction between actin
and myosin.
- answer-:
1. Action potential arrives at the neuromuscular junction → triggers acetylcholine (ACh) release.
2. ACh binds to receptors on the motor end plate → depolarization of sarcolemma.
3. Action potential propagates along the sarcolemma and T-tubules.
4. Depolarization of T-tubules triggers calcium release from the SR.
5. Calcium binds to troponin, causing a conformational change → moves tropomyosin off actin’s
binding sites.
6. Myosin heads bind actin → cross-bridge cycling begins → sarcomere shortens → muscle
contraction.
Explanation: Calcium is the key regulator; without Ca²⁺, troponin-tropomyosin blocks actin-myosin
interaction, preventing contraction.
2. Question:
Compare and contrast the mechanisms of primary active transport and secondary active transport in
cells. Provide an example of each and explain how they maintain homeostasis in the human body.
- answer-:
, • Primary active transport: Uses ATP directly to move molecules against their concentration
gradient.
o Example: Sodium-potassium pump (Na⁺/K⁺ ATPase) maintains resting membrane
potential.
• Secondary active transport: Uses energy stored in the gradient of one molecule to move
another molecule against its gradient.
o Example: Sodium-glucose cotransporter (SGLT) in the intestine.
Explanation: Both maintain homeostasis by regulating ion concentrations and nutrient absorption.
Primary uses direct ATP hydrolysis, while secondary relies on gradients created by primary transport.
3. Question:
Explain the differences between endocrine and exocrine glands in terms of structure, function, and the
type of secretions they produce. Include two examples of each.
- answer-:
• Endocrine glands: Ductless, release hormones into the blood → affect distant organs.
o Examples: Thyroid gland (T3/T4), adrenal cortex (cortisol).
• Exocrine glands: Secrete products through ducts → act locally.
o Examples: Salivary glands (saliva), pancreas (digestive enzymes).
Explanation: The key difference is the presence of ducts and systemic vs. local effects. Hormones from
endocrine glands regulate metabolism, growth, and homeostasis, while exocrine secretions aid digestion
or protection.
4. Question:
Describe the electrochemical basis of resting membrane potential in neurons. Include the roles of Na⁺,
K⁺, Cl⁻, and the sodium-potassium pump.
- answer-:
• Resting potential ≈ -70 mV.
• K⁺ leak channels allow K⁺ to move out → more negative inside.
• Na⁺ concentration higher outside; Na⁺ wants to move in but channels are mostly closed.
• Cl⁻ ions move passively to balance charge.
• Na⁺/K⁺ ATPase pumps 3 Na⁺ out, 2 K⁺ in → maintains gradients.
Explanation: The uneven distribution of ions and selective membrane permeability creates a negative
resting potential essential for action potential generation.
,5. Question:
Compare compact bone and spongy bone regarding their histology, location, and mechanical function.
Why is spongy bone more metabolically active than compact bone?
- answer-:
• Compact bone: Dense, forms the shaft of long bones, provides strength, contains osteons
(Haversian systems).
• Spongy bone: Porous, located at epiphyses, contains trabeculae, reduces bone weight, houses
red marrow.
Explanation: Spongy bone has higher surface area and is more metabolically active because of abundant
bone marrow and vascular spaces, facilitating hematopoiesis and nutrient exchange.
6. Question:
Explain the differences between skeletal, cardiac, and smooth muscle in terms of structure, control,
and physiological function. Include how each type responds to stimulation.
- answer-:
Feature Skeletal Cardiac Smooth
Control Voluntary Involuntary Involuntary
Striations Present Present Absent
Nuclei Multinucleated 1-2 Single
Stimulation Neuromuscular junction Pacemaker + autonomic Autonomic, hormones, stretch
Function Movement, posture Heart pumping Viscera movement, vessel diameter
Explanation: Structural differences correspond to function: skeletal for rapid voluntary movement,
cardiac for rhythmic heart contractions, smooth for sustained contractions in organs.
7. Question:
Describe negative feedback and positive feedback mechanisms in physiology. Give one detailed
example of each, explaining the roles of sensors, integrators, and effectors.
- answer-:
• Negative feedback: Opposes change → maintains homeostasis.
o Example: Blood glucose regulation.
, ▪ Sensor: Pancreatic beta cells detect ↑ glucose.
▪ Effector: Insulin released → glucose uptake by cells → glucose ↓.
• Positive feedback: Amplifies change → moves system away from baseline.
o Example: Labor contractions.
▪ Sensor: Cervical stretch receptors.
▪ Effector: Oxytocin released → stronger contractions → further cervical stretch.
Explanation: Negative feedback stabilizes, positive feedback amplifies temporary events; most
homeostatic mechanisms are negative.
8. Question:
Discuss the functional anatomy of the nephron in the kidney. Include the roles of the glomerulus,
proximal tubule, loop of Henle, distal tubule, and collecting duct in urine formation.
- answer-:
1. Glomerulus: Filters blood → filtrate contains water, ions, glucose, urea.
2. Proximal tubule: Reabsorbs ~65% of water, ions, nutrients.
3. Loop of Henle: Establishes osmotic gradient → water reabsorption in descending limb, Na⁺
reabsorption in ascending limb.
4. Distal tubule: Fine-tunes electrolyte balance, pH.
5. Collecting duct: Final concentration of urine → regulated by ADH.
Explanation: The nephron’s segmented function allows precise regulation of fluid and electrolyte
balance.
9. Question:
Explain the differences between isotonic, hypertonic, and hypotonic solutions in terms of osmotic
effects on cells. Include a clinical example for each.
- answer-:
• Isotonic: Equal solute concentration → no net water movement.
o Example: 0.9% NaCl for IV fluid replacement.
• Hypertonic: Higher solute outside → water leaves cell → cell shrinks.
o Example: 3% NaCl for cerebral edema.
• Hypotonic: Lower solute outside → water enters cell → cell swells.
CORRECT ANSWERS IVY TECH COMMUNITY COLLEGE
INDIANAPOLIS
APHY 101 – 200 QUESTIONS Midterm Exam: 0 Most Tested & Difficult Questions
1. Question:
The sarcoplasmic reticulum (SR) in skeletal muscle fibers plays a critical role during muscle contraction.
Describe the sequence of events from the arrival of an action potential at the neuromuscular junction to
the contraction of the sarcomere, and explain how calcium ions regulate the interaction between actin
and myosin.
- answer-:
1. Action potential arrives at the neuromuscular junction → triggers acetylcholine (ACh) release.
2. ACh binds to receptors on the motor end plate → depolarization of sarcolemma.
3. Action potential propagates along the sarcolemma and T-tubules.
4. Depolarization of T-tubules triggers calcium release from the SR.
5. Calcium binds to troponin, causing a conformational change → moves tropomyosin off actin’s
binding sites.
6. Myosin heads bind actin → cross-bridge cycling begins → sarcomere shortens → muscle
contraction.
Explanation: Calcium is the key regulator; without Ca²⁺, troponin-tropomyosin blocks actin-myosin
interaction, preventing contraction.
2. Question:
Compare and contrast the mechanisms of primary active transport and secondary active transport in
cells. Provide an example of each and explain how they maintain homeostasis in the human body.
- answer-:
, • Primary active transport: Uses ATP directly to move molecules against their concentration
gradient.
o Example: Sodium-potassium pump (Na⁺/K⁺ ATPase) maintains resting membrane
potential.
• Secondary active transport: Uses energy stored in the gradient of one molecule to move
another molecule against its gradient.
o Example: Sodium-glucose cotransporter (SGLT) in the intestine.
Explanation: Both maintain homeostasis by regulating ion concentrations and nutrient absorption.
Primary uses direct ATP hydrolysis, while secondary relies on gradients created by primary transport.
3. Question:
Explain the differences between endocrine and exocrine glands in terms of structure, function, and the
type of secretions they produce. Include two examples of each.
- answer-:
• Endocrine glands: Ductless, release hormones into the blood → affect distant organs.
o Examples: Thyroid gland (T3/T4), adrenal cortex (cortisol).
• Exocrine glands: Secrete products through ducts → act locally.
o Examples: Salivary glands (saliva), pancreas (digestive enzymes).
Explanation: The key difference is the presence of ducts and systemic vs. local effects. Hormones from
endocrine glands regulate metabolism, growth, and homeostasis, while exocrine secretions aid digestion
or protection.
4. Question:
Describe the electrochemical basis of resting membrane potential in neurons. Include the roles of Na⁺,
K⁺, Cl⁻, and the sodium-potassium pump.
- answer-:
• Resting potential ≈ -70 mV.
• K⁺ leak channels allow K⁺ to move out → more negative inside.
• Na⁺ concentration higher outside; Na⁺ wants to move in but channels are mostly closed.
• Cl⁻ ions move passively to balance charge.
• Na⁺/K⁺ ATPase pumps 3 Na⁺ out, 2 K⁺ in → maintains gradients.
Explanation: The uneven distribution of ions and selective membrane permeability creates a negative
resting potential essential for action potential generation.
,5. Question:
Compare compact bone and spongy bone regarding their histology, location, and mechanical function.
Why is spongy bone more metabolically active than compact bone?
- answer-:
• Compact bone: Dense, forms the shaft of long bones, provides strength, contains osteons
(Haversian systems).
• Spongy bone: Porous, located at epiphyses, contains trabeculae, reduces bone weight, houses
red marrow.
Explanation: Spongy bone has higher surface area and is more metabolically active because of abundant
bone marrow and vascular spaces, facilitating hematopoiesis and nutrient exchange.
6. Question:
Explain the differences between skeletal, cardiac, and smooth muscle in terms of structure, control,
and physiological function. Include how each type responds to stimulation.
- answer-:
Feature Skeletal Cardiac Smooth
Control Voluntary Involuntary Involuntary
Striations Present Present Absent
Nuclei Multinucleated 1-2 Single
Stimulation Neuromuscular junction Pacemaker + autonomic Autonomic, hormones, stretch
Function Movement, posture Heart pumping Viscera movement, vessel diameter
Explanation: Structural differences correspond to function: skeletal for rapid voluntary movement,
cardiac for rhythmic heart contractions, smooth for sustained contractions in organs.
7. Question:
Describe negative feedback and positive feedback mechanisms in physiology. Give one detailed
example of each, explaining the roles of sensors, integrators, and effectors.
- answer-:
• Negative feedback: Opposes change → maintains homeostasis.
o Example: Blood glucose regulation.
, ▪ Sensor: Pancreatic beta cells detect ↑ glucose.
▪ Effector: Insulin released → glucose uptake by cells → glucose ↓.
• Positive feedback: Amplifies change → moves system away from baseline.
o Example: Labor contractions.
▪ Sensor: Cervical stretch receptors.
▪ Effector: Oxytocin released → stronger contractions → further cervical stretch.
Explanation: Negative feedback stabilizes, positive feedback amplifies temporary events; most
homeostatic mechanisms are negative.
8. Question:
Discuss the functional anatomy of the nephron in the kidney. Include the roles of the glomerulus,
proximal tubule, loop of Henle, distal tubule, and collecting duct in urine formation.
- answer-:
1. Glomerulus: Filters blood → filtrate contains water, ions, glucose, urea.
2. Proximal tubule: Reabsorbs ~65% of water, ions, nutrients.
3. Loop of Henle: Establishes osmotic gradient → water reabsorption in descending limb, Na⁺
reabsorption in ascending limb.
4. Distal tubule: Fine-tunes electrolyte balance, pH.
5. Collecting duct: Final concentration of urine → regulated by ADH.
Explanation: The nephron’s segmented function allows precise regulation of fluid and electrolyte
balance.
9. Question:
Explain the differences between isotonic, hypertonic, and hypotonic solutions in terms of osmotic
effects on cells. Include a clinical example for each.
- answer-:
• Isotonic: Equal solute concentration → no net water movement.
o Example: 0.9% NaCl for IV fluid replacement.
• Hypertonic: Higher solute outside → water leaves cell → cell shrinks.
o Example: 3% NaCl for cerebral edema.
• Hypotonic: Lower solute outside → water enters cell → cell swells.
