BIOD 152 Module 1 Exam: Anatomy & Physiology II - Nervous System
2026/2027 UPDATE
1. Which neuroglial cell is responsible for forming the myelin sheath in the
Central Nervous System (CNS)?
A. Schwann cells
B. Microglia
C. Astrocytes
D. Oligodendrocytes
Answer: D
Rationale: Oligodendrocytes form myelin in the CNS, while Schwann cells perform this
function in the Peripheral Nervous System (PNS).
2. What is the typical resting membrane potential of a neuron?
A. +30 mV
B. -55 mV
C. -70 mV
D. 0 mV
Answer: C
Rationale: The resting membrane potential is typically -70 mV, maintained by the sodium-
potassium pump and leak channels.
,3. During an action potential, which ion primarily enters the cell causing
depolarization?
A. Sodium (Na+)
B. Calcium (Ca2+)
C. Chloride (Cl-)
D. Potassium (K+)
Answer: A
Rationale: Depolarization occurs when voltage-gated sodium channels open, allowing Na+
to rush into the cell down its electrochemical gradient.
4. Which part of the nervous system is often referred to as the ‘rest and digest’
system?
A. Sympathetic Nervous System
B. Somatic Nervous System
C. Central Nervous System
D. Parasympathetic Nervous System
Answer: D
Rationale: The Parasympathetic division of the Autonomic Nervous System (ANS)
conserves energy and promotes housekeeping functions.
5. In a reflex arc, which component sends the signal to the effector organ?
A. Sensory neuron
B. Motor neuron
C. Interneuron
D. Receptor
Answer: B
Rationale: The motor (efferent) neuron carries the command from the integration center
to the effector, such as a muscle or gland.
, 6. What is the function of microglia cells?
A. Creating cerebrospinal fluid
B. Acting as phagocytes to remove debris
C. Regulating the blood-brain barrier
D. Insulating axons
Answer: B
Rationale: Microglia are the immune cells of the CNS, functioning as phagocytes to protect
against pathogens and clear dead cells.
7. The ‘All-or-None’ principle states that:
A. Once threshold is reached, an action potential occurs at full strength
B. Stronger stimuli produce larger action potentials
C. All stimuli will produce an action potential
D. Neurons only fire when they are at +30 mV
Answer: A
Rationale: The All-or-None principle means that if a stimulus reaches threshold, an action
potential happens completely; if not, it does not happen at all.
8. Which of the following is an example of a monosynaptic reflex?
A. The withdrawal reflex
B. The knee-jerk (stretch) reflex
C. The crossed-extensor reflex
D. The pupillary light reflex
Answer: B
Rationale: A monosynaptic reflex, like the knee-jerk reflex, involves only one synapse
between a sensory neuron and a motor neuron.
2026/2027 UPDATE
1. Which neuroglial cell is responsible for forming the myelin sheath in the
Central Nervous System (CNS)?
A. Schwann cells
B. Microglia
C. Astrocytes
D. Oligodendrocytes
Answer: D
Rationale: Oligodendrocytes form myelin in the CNS, while Schwann cells perform this
function in the Peripheral Nervous System (PNS).
2. What is the typical resting membrane potential of a neuron?
A. +30 mV
B. -55 mV
C. -70 mV
D. 0 mV
Answer: C
Rationale: The resting membrane potential is typically -70 mV, maintained by the sodium-
potassium pump and leak channels.
,3. During an action potential, which ion primarily enters the cell causing
depolarization?
A. Sodium (Na+)
B. Calcium (Ca2+)
C. Chloride (Cl-)
D. Potassium (K+)
Answer: A
Rationale: Depolarization occurs when voltage-gated sodium channels open, allowing Na+
to rush into the cell down its electrochemical gradient.
4. Which part of the nervous system is often referred to as the ‘rest and digest’
system?
A. Sympathetic Nervous System
B. Somatic Nervous System
C. Central Nervous System
D. Parasympathetic Nervous System
Answer: D
Rationale: The Parasympathetic division of the Autonomic Nervous System (ANS)
conserves energy and promotes housekeeping functions.
5. In a reflex arc, which component sends the signal to the effector organ?
A. Sensory neuron
B. Motor neuron
C. Interneuron
D. Receptor
Answer: B
Rationale: The motor (efferent) neuron carries the command from the integration center
to the effector, such as a muscle or gland.
, 6. What is the function of microglia cells?
A. Creating cerebrospinal fluid
B. Acting as phagocytes to remove debris
C. Regulating the blood-brain barrier
D. Insulating axons
Answer: B
Rationale: Microglia are the immune cells of the CNS, functioning as phagocytes to protect
against pathogens and clear dead cells.
7. The ‘All-or-None’ principle states that:
A. Once threshold is reached, an action potential occurs at full strength
B. Stronger stimuli produce larger action potentials
C. All stimuli will produce an action potential
D. Neurons only fire when they are at +30 mV
Answer: A
Rationale: The All-or-None principle means that if a stimulus reaches threshold, an action
potential happens completely; if not, it does not happen at all.
8. Which of the following is an example of a monosynaptic reflex?
A. The withdrawal reflex
B. The knee-jerk (stretch) reflex
C. The crossed-extensor reflex
D. The pupillary light reflex
Answer: B
Rationale: A monosynaptic reflex, like the knee-jerk reflex, involves only one synapse
between a sensory neuron and a motor neuron.
