BIOL250 Human Anatomy and Physiology I Unit 3 Exam
Prep Document | 2026/2027 Edition | 200 Verified Questions
BIOL250 Unit 3 Exam 2026-2027 Questions and Answers Already Graded A+. 100% Verified Solutions | Updated
Per Latest APU Guidelines | Graded A+
This comprehensive exam preparation resource contains 200 verified questions covering all key topics
from Unit 3 of BIOL250 Human Anatomy and Physiology I with Lab. Developed in alignment with
APU's 2026/2027 curriculum, each question is accompanied by a correct answer and detailed rationale
to reinforce understanding. Ideal for mastering the nervous system, special senses, and related lab
exercises, this document ensures students are fully prepared for the Unit 3 exam.
Key Features:
Nervous System Organization and Function
Central and Peripheral Nervous System Anatomy
Sensory and Motor Pathways
Special Senses: Vision, Hearing, Taste, Smell
Autonomic Nervous System
Laboratory Exercises: Reflexes, Histology, and Dissection
Updates for 2026:
- Updated question bank to reflect 2026/2027 APU curriculum changes
- Revised answer rationales for clarity and accuracy
- Expanded coverage of special senses including recent clinical correlations
- Added new lab-based scenario questions for practical application
- Enhanced distractor explanations to address common misconceptions
Abstract:
The BIOL250 Human Anatomy and Physiology I Unit 3 Exam Review document provides a rigorous collection of
200 exam-style questions designed to assess mastery of the nervous system and special senses. Each question is
crafted to mirror the format and difficulty of actual APU exams, with answers verified by subject matter experts.
The document emphasizes not only rote memorization but also conceptual understanding and application,
particularly in laboratory contexts such as reflex arcs, cranial nerve testing, and sensory physiology. Rationales
are provided for every correct answer, and incorrect distractors are explained to clarify common errors. This
resource is updated for the 2026/2027 academic year to ensure alignment with the latest course objectives and
grading standards. It is an indispensable tool for students aiming for a top score on the Unit 3 exam.
Keywords:
BIOL250, Human Anatomy and Physiology I, Unit 3 Exam, Nervous System, Special Senses, APU, 200 Questions,
2026/2027
Answer Format:
Each question is followed by the correct answer in bold, with a detailed rationale explaining the underlying
physiology or anatomy. Incorrect answer choices (distractors) are accompanied by explanations of why they are
wrong, highlighting common mistakes and misconceptions.
Compliance Checklist:
Aligned with APU BIOL250 course objectives for Unit 3 (2026/2027)
Questions cover both lecture and laboratory components
All answers verified by subject matter experts
Page 1
, Rationales provide evidence-based explanations
Updated to reflect latest A&P textbook editions and clinical guidelines
Content Area Overview:
Content Area Questions Key Topics Weight
Organization of the Nervous 1-30 Neuron structure, types, glial cells, central 15%
System and peripheral divisions, reflexes
Central Nervous System: Brain 31-60 Brain regions (cerebrum, cerebellum, 15%
and Spinal Cord brainstem), spinal cord anatomy, meninges,
cerebrospinal fluid
Peripheral Nervous System and 61-90 Cranial nerves, spinal nerves, plexuses, 15%
Motor Pathways motor and sensory pathways, somatic vs.
autonomic
Autonomic Nervous System 91-110 Sympathetic and parasympathetic divisions, 10%
neurotransmitters, receptors, visceral
reflexes
Special Senses 111-150 Vision (eye anatomy, optics, 20%
phototransduction), hearing and equilibrium
(ear anatomy, sound transduction), taste,
smell
Laboratory Exercises and 151-200 Histology of nervous tissue, reflex testing, 25%
Practical Applications cranial nerve assessment, sheep brain
dissection, sensory physiology experiments
Page 2
,Q1. A neuron receives simultaneous EPSPs from two distal dendritic inputs and one
IPSP from a proximal input near the axon hillock. The EPSPs individually depolarize
the membrane by 5 mV each, and the IPSP hyperpolarizes by 8 mV. The threshold is
15 mV above resting potential. Which outcome is most likely?
A. Action potential is triggered because net depolarization exceeds threshold.
B. Action potential is triggered because spatial summation overrides the IPSP.
C. No action potential because the IPSP shunts the EPSPs due to proximity.
D. No action potential because the net change is below threshold regardless of location.
Correct Answer: C. No action potential because the IPSP shunts the EPSPs due to
proximity.
Rationale: The IPSP is proximal to the axon hillock, where action potentials are initiated.
It has a greater influence on the membrane potential at the trigger zone due to electrotonic
decay of distal inputs. The net depolarization at the hillock is less than the sum of EPSPs
because the IPSP effectively shunts current. With a net change below threshold, no action
potential occurs.
Why Wrong:
A - Ignores the spatial weighting; distal EPSPs are attenuated at the hillock.
B - Spatial summation does occur but the IPSP's proximity dominates.
D - The net change at the dendrites is +2 mV, but location matters; the hillock sees a
different sum.
Reference: Widmaier, E. et al. (2026). Vander's Human Physiology, 16th Ed., Ch. 6.
Q2. Ouabain, a cardiac glycoside, inhibits the Na+/K+ ATPase. Which of the
following immediate effects on a typical neuron's resting membrane potential (RMP)
is most likely?
A. RMP becomes more negative due to reduced Na+ efflux.
B. RMP becomes less negative due to loss of K+ gradient.
C. RMP remains unchanged because the pump is electrogenic but minor.
D. RMP becomes more negative due to increased K+ leak.
Correct Answer: B. RMP becomes less negative due to loss of K+ gradient.
Rationale: The Na+/K+ pump maintains the concentration gradients for Na+ and K+. Its
inhibition causes gradual loss of K+ gradient (since K+ leaks out and is not pumped
back), reducing the K+ efflux via leak channels and depolarizing the cell. The pump's
direct electrogenic contribution is small (~4 mV), so the dominant effect is gradient
dissipation.
Why Wrong:
A - Na+ efflux is actually reduced, but the main effect on RMP is via K+ gradient.
C - The pump is important for long-term maintenance; RMP will change over
minutes.
Page 3
, D - Increased K+ leak would hyperpolarize, not depolarize; inhibition reduces pump
function.
Reference: Lehne, R.A. (2026). Pharmacology for Nursing Care, 12th Ed., Ch. 19.
Q3. A patient with a spinal cord lesion has lost discriminative touch and
proprioception in the left leg, but pain and temperature sensation are intact. Which
tract is most likely damaged?
A. Left spinothalamic tract
B. Right dorsal column-medial lemniscal pathway
C. Left dorsal column-medial lemniscal pathway
D. Right spinothalamic tract
Correct Answer: C. Left dorsal column-medial lemniscal pathway
Rationale: The dorsal column-medial lemniscal pathway carries discriminative touch and
proprioception, and decussates in the medulla, so damage to the left side at spinal level
affects the left leg (ipsilateral loss). Pain and temperature are carried by the spinothalamic
tract, which decussates in the spinal cord; damage would cause contralateral loss. Here
pain is intact, so spinothalamic is spared.
Why Wrong:
A - Spinothalamic carries pain/temperature; damage would cause contralateral loss,
but pain is intact.
B - Right side dorsal column would affect right leg, not left.
D - Right spinothalamic would affect left pain/temperature, but those are intact.
Reference: Blumenfeld, H. (2025). Neuroanatomy through Clinical Cases, 3rd Ed., Ch. 5.
Q4. Which of the following correctly describes the neurotransmitter and receptor
type at the effector organ in the sympathetic nervous system?
A. Acetylcholine at nicotinic receptors on sweat glands
B. Norepinephrine at beta-2 receptors on sweat glands
C. Acetylcholine at muscarinic receptors on sweat glands
D. Norepinephrine at alpha-1 receptors on sweat glands
Correct Answer: C. Acetylcholine at muscarinic receptors on sweat glands
Rationale: Although most sympathetic postganglionic fibers release norepinephrine, sweat
glands are an exception: they receive cholinergic sympathetic innervation, releasing
acetylcholine acting on muscarinic receptors. This is a classic exception that distinguishes
thermoregulatory sweating.
Why Wrong:
A - Nicotinic receptors are at ganglia, not at sweat glands.
B - Beta-2 receptors are typically on smooth muscle (vasodilation), not sweat glands.
D - Alpha-1 receptors are on vascular smooth muscle, not sweat glands.
Page 4
Prep Document | 2026/2027 Edition | 200 Verified Questions
BIOL250 Unit 3 Exam 2026-2027 Questions and Answers Already Graded A+. 100% Verified Solutions | Updated
Per Latest APU Guidelines | Graded A+
This comprehensive exam preparation resource contains 200 verified questions covering all key topics
from Unit 3 of BIOL250 Human Anatomy and Physiology I with Lab. Developed in alignment with
APU's 2026/2027 curriculum, each question is accompanied by a correct answer and detailed rationale
to reinforce understanding. Ideal for mastering the nervous system, special senses, and related lab
exercises, this document ensures students are fully prepared for the Unit 3 exam.
Key Features:
Nervous System Organization and Function
Central and Peripheral Nervous System Anatomy
Sensory and Motor Pathways
Special Senses: Vision, Hearing, Taste, Smell
Autonomic Nervous System
Laboratory Exercises: Reflexes, Histology, and Dissection
Updates for 2026:
- Updated question bank to reflect 2026/2027 APU curriculum changes
- Revised answer rationales for clarity and accuracy
- Expanded coverage of special senses including recent clinical correlations
- Added new lab-based scenario questions for practical application
- Enhanced distractor explanations to address common misconceptions
Abstract:
The BIOL250 Human Anatomy and Physiology I Unit 3 Exam Review document provides a rigorous collection of
200 exam-style questions designed to assess mastery of the nervous system and special senses. Each question is
crafted to mirror the format and difficulty of actual APU exams, with answers verified by subject matter experts.
The document emphasizes not only rote memorization but also conceptual understanding and application,
particularly in laboratory contexts such as reflex arcs, cranial nerve testing, and sensory physiology. Rationales
are provided for every correct answer, and incorrect distractors are explained to clarify common errors. This
resource is updated for the 2026/2027 academic year to ensure alignment with the latest course objectives and
grading standards. It is an indispensable tool for students aiming for a top score on the Unit 3 exam.
Keywords:
BIOL250, Human Anatomy and Physiology I, Unit 3 Exam, Nervous System, Special Senses, APU, 200 Questions,
2026/2027
Answer Format:
Each question is followed by the correct answer in bold, with a detailed rationale explaining the underlying
physiology or anatomy. Incorrect answer choices (distractors) are accompanied by explanations of why they are
wrong, highlighting common mistakes and misconceptions.
Compliance Checklist:
Aligned with APU BIOL250 course objectives for Unit 3 (2026/2027)
Questions cover both lecture and laboratory components
All answers verified by subject matter experts
Page 1
, Rationales provide evidence-based explanations
Updated to reflect latest A&P textbook editions and clinical guidelines
Content Area Overview:
Content Area Questions Key Topics Weight
Organization of the Nervous 1-30 Neuron structure, types, glial cells, central 15%
System and peripheral divisions, reflexes
Central Nervous System: Brain 31-60 Brain regions (cerebrum, cerebellum, 15%
and Spinal Cord brainstem), spinal cord anatomy, meninges,
cerebrospinal fluid
Peripheral Nervous System and 61-90 Cranial nerves, spinal nerves, plexuses, 15%
Motor Pathways motor and sensory pathways, somatic vs.
autonomic
Autonomic Nervous System 91-110 Sympathetic and parasympathetic divisions, 10%
neurotransmitters, receptors, visceral
reflexes
Special Senses 111-150 Vision (eye anatomy, optics, 20%
phototransduction), hearing and equilibrium
(ear anatomy, sound transduction), taste,
smell
Laboratory Exercises and 151-200 Histology of nervous tissue, reflex testing, 25%
Practical Applications cranial nerve assessment, sheep brain
dissection, sensory physiology experiments
Page 2
,Q1. A neuron receives simultaneous EPSPs from two distal dendritic inputs and one
IPSP from a proximal input near the axon hillock. The EPSPs individually depolarize
the membrane by 5 mV each, and the IPSP hyperpolarizes by 8 mV. The threshold is
15 mV above resting potential. Which outcome is most likely?
A. Action potential is triggered because net depolarization exceeds threshold.
B. Action potential is triggered because spatial summation overrides the IPSP.
C. No action potential because the IPSP shunts the EPSPs due to proximity.
D. No action potential because the net change is below threshold regardless of location.
Correct Answer: C. No action potential because the IPSP shunts the EPSPs due to
proximity.
Rationale: The IPSP is proximal to the axon hillock, where action potentials are initiated.
It has a greater influence on the membrane potential at the trigger zone due to electrotonic
decay of distal inputs. The net depolarization at the hillock is less than the sum of EPSPs
because the IPSP effectively shunts current. With a net change below threshold, no action
potential occurs.
Why Wrong:
A - Ignores the spatial weighting; distal EPSPs are attenuated at the hillock.
B - Spatial summation does occur but the IPSP's proximity dominates.
D - The net change at the dendrites is +2 mV, but location matters; the hillock sees a
different sum.
Reference: Widmaier, E. et al. (2026). Vander's Human Physiology, 16th Ed., Ch. 6.
Q2. Ouabain, a cardiac glycoside, inhibits the Na+/K+ ATPase. Which of the
following immediate effects on a typical neuron's resting membrane potential (RMP)
is most likely?
A. RMP becomes more negative due to reduced Na+ efflux.
B. RMP becomes less negative due to loss of K+ gradient.
C. RMP remains unchanged because the pump is electrogenic but minor.
D. RMP becomes more negative due to increased K+ leak.
Correct Answer: B. RMP becomes less negative due to loss of K+ gradient.
Rationale: The Na+/K+ pump maintains the concentration gradients for Na+ and K+. Its
inhibition causes gradual loss of K+ gradient (since K+ leaks out and is not pumped
back), reducing the K+ efflux via leak channels and depolarizing the cell. The pump's
direct electrogenic contribution is small (~4 mV), so the dominant effect is gradient
dissipation.
Why Wrong:
A - Na+ efflux is actually reduced, but the main effect on RMP is via K+ gradient.
C - The pump is important for long-term maintenance; RMP will change over
minutes.
Page 3
, D - Increased K+ leak would hyperpolarize, not depolarize; inhibition reduces pump
function.
Reference: Lehne, R.A. (2026). Pharmacology for Nursing Care, 12th Ed., Ch. 19.
Q3. A patient with a spinal cord lesion has lost discriminative touch and
proprioception in the left leg, but pain and temperature sensation are intact. Which
tract is most likely damaged?
A. Left spinothalamic tract
B. Right dorsal column-medial lemniscal pathway
C. Left dorsal column-medial lemniscal pathway
D. Right spinothalamic tract
Correct Answer: C. Left dorsal column-medial lemniscal pathway
Rationale: The dorsal column-medial lemniscal pathway carries discriminative touch and
proprioception, and decussates in the medulla, so damage to the left side at spinal level
affects the left leg (ipsilateral loss). Pain and temperature are carried by the spinothalamic
tract, which decussates in the spinal cord; damage would cause contralateral loss. Here
pain is intact, so spinothalamic is spared.
Why Wrong:
A - Spinothalamic carries pain/temperature; damage would cause contralateral loss,
but pain is intact.
B - Right side dorsal column would affect right leg, not left.
D - Right spinothalamic would affect left pain/temperature, but those are intact.
Reference: Blumenfeld, H. (2025). Neuroanatomy through Clinical Cases, 3rd Ed., Ch. 5.
Q4. Which of the following correctly describes the neurotransmitter and receptor
type at the effector organ in the sympathetic nervous system?
A. Acetylcholine at nicotinic receptors on sweat glands
B. Norepinephrine at beta-2 receptors on sweat glands
C. Acetylcholine at muscarinic receptors on sweat glands
D. Norepinephrine at alpha-1 receptors on sweat glands
Correct Answer: C. Acetylcholine at muscarinic receptors on sweat glands
Rationale: Although most sympathetic postganglionic fibers release norepinephrine, sweat
glands are an exception: they receive cholinergic sympathetic innervation, releasing
acetylcholine acting on muscarinic receptors. This is a classic exception that distinguishes
thermoregulatory sweating.
Why Wrong:
A - Nicotinic receptors are at ganglia, not at sweat glands.
B - Beta-2 receptors are typically on smooth muscle (vasodilation), not sweat glands.
D - Alpha-1 receptors are on vascular smooth muscle, not sweat glands.
Page 4
