A R I Z O N A S TAT E U N I V E R S I T Y · S C H O O L O F L I F E S C I E N C E S
BIO 181 Exam 3
Practice Question Bank
Comprehensive Review with Rationales
Topics: Nervous System · Cardiovascular · Respiratory · Renal · Endocrine ·
Homeostasis
Edition 1 · August 2026
Table of Contents
1. Instructions for Use 2
2. Nervous System & Synaptic Transmission 2
3. Endocrine System & Homeostasis 4
4. Cardiovascular System & Circulation 5
,5. Respiratory System 6
6. Renal System & Kidney Function 7
ASU BIO 181 · Arizona State University Page 1
,ASU BIO 181 EXAM 3 PRACTICE GUIDE INSTRUCTIONS & NERVOUS SYSTEM
How to Use This Guide
Read each stem, choose your answer, then check the rationale directly below it. The correct
option is marked, and each wrong option is explained so you understand why it's wrong — not
just that it is. Items marked NEEDS RATIONALE had limited source detail; treat those as flags
for independent review.
Nervous System & Synaptic Transmission
1 Excitatory synapses make the post-synaptic cell less likely to fire. True or false?
A True
B False
Why B is correct: Excitatory synapses depolarize the post-synaptic cell, making it MORE
likely to fire an action potential.
A — This describes inhibitory synapses, which hyperpolarize the cell and make it less likely to
fire.
2 The neural tissues are:
A Spinal cord, sensory neurons, and brain
B Brain, spinal cord, and motor neurons
C Sensory neurons, motor neurons, and interneurons
D Brain, peripheral nerves, and ganglia
Why A is correct: Neural tissues include the brain (CNS), spinal cord (CNS), and sensory
neurons (PNS).
B — Motor neurons are also neural tissue, but this omits sensory neurons.
C — This describes neuron types, not neural tissues.
D — Ganglia are clusters of neuron cell bodies in the PNS, but this is less complete.
, 3 How do the glial cells (myelin sheath) speed up the firing of neurons?
A The cell wraps extensions of a fatty insulating substance (myelin) around the axons
of neurons
B They directly conduct electrical signals faster
C They release neurotransmitters that speed up firing
D They increase the diameter of the axon
Why A is correct: Myelin sheaths insulate axons, allowing saltatory conduction where
action potentials "jump" between Nodes of Ranvier.
B — Glial cells do not conduct electrical signals; they support and insulate neurons.
C — Neurotransmitters are released by neurons, not glial cells.
D — Axon diameter affects speed, but this is not how myelin speeds up firing.
4 The action potential is:
A A result of the movement of ions
B A chemical signal transmitted across the synapse
C A protein-based signaling cascade
D A change in gene expression
Why A is correct: Action potentials are electrical signals caused by the movement of Na⁺
and K⁺ ions across the neuronal membrane.
B — This describes neurotransmitter signaling at synapses.
C — This describes signal transduction pathways.
D — Gene expression changes occur over longer timescales.
BIO 181 Exam 3
Practice Question Bank
Comprehensive Review with Rationales
Topics: Nervous System · Cardiovascular · Respiratory · Renal · Endocrine ·
Homeostasis
Edition 1 · August 2026
Table of Contents
1. Instructions for Use 2
2. Nervous System & Synaptic Transmission 2
3. Endocrine System & Homeostasis 4
4. Cardiovascular System & Circulation 5
,5. Respiratory System 6
6. Renal System & Kidney Function 7
ASU BIO 181 · Arizona State University Page 1
,ASU BIO 181 EXAM 3 PRACTICE GUIDE INSTRUCTIONS & NERVOUS SYSTEM
How to Use This Guide
Read each stem, choose your answer, then check the rationale directly below it. The correct
option is marked, and each wrong option is explained so you understand why it's wrong — not
just that it is. Items marked NEEDS RATIONALE had limited source detail; treat those as flags
for independent review.
Nervous System & Synaptic Transmission
1 Excitatory synapses make the post-synaptic cell less likely to fire. True or false?
A True
B False
Why B is correct: Excitatory synapses depolarize the post-synaptic cell, making it MORE
likely to fire an action potential.
A — This describes inhibitory synapses, which hyperpolarize the cell and make it less likely to
fire.
2 The neural tissues are:
A Spinal cord, sensory neurons, and brain
B Brain, spinal cord, and motor neurons
C Sensory neurons, motor neurons, and interneurons
D Brain, peripheral nerves, and ganglia
Why A is correct: Neural tissues include the brain (CNS), spinal cord (CNS), and sensory
neurons (PNS).
B — Motor neurons are also neural tissue, but this omits sensory neurons.
C — This describes neuron types, not neural tissues.
D — Ganglia are clusters of neuron cell bodies in the PNS, but this is less complete.
, 3 How do the glial cells (myelin sheath) speed up the firing of neurons?
A The cell wraps extensions of a fatty insulating substance (myelin) around the axons
of neurons
B They directly conduct electrical signals faster
C They release neurotransmitters that speed up firing
D They increase the diameter of the axon
Why A is correct: Myelin sheaths insulate axons, allowing saltatory conduction where
action potentials "jump" between Nodes of Ranvier.
B — Glial cells do not conduct electrical signals; they support and insulate neurons.
C — Neurotransmitters are released by neurons, not glial cells.
D — Axon diameter affects speed, but this is not how myelin speeds up firing.
4 The action potential is:
A A result of the movement of ions
B A chemical signal transmitted across the synapse
C A protein-based signaling cascade
D A change in gene expression
Why A is correct: Action potentials are electrical signals caused by the movement of Na⁺
and K⁺ ions across the neuronal membrane.
B — This describes neurotransmitter signaling at synapses.
C — This describes signal transduction pathways.
D — Gene expression changes occur over longer timescales.
