BIO105 | BIO105 Anatomy and Physiology 1 Exam
3 Version 1 | Questions with Correct Answers and
Expert Explanation for Each Question | Saint Paul’s
School of Nursing
1. Which component of the nervous system is primarily responsible for integrating
sensory information and initiating a motor response?
A. Peripheral Nervous System
B. Somatic Nervous System
C. Central Nervous System
D. Autonomic Nervous System
Correct Answer: C
Expert Explanation: The central nervous system consists of the brain and spinal
cord. It serves as the main integration and command center for the entire body.
Sensory input is received and processed here to determine the appropriate motor
output. This system coordinates complex activities and ensures that physiological
responses are synchronized. It is structurally separated from the peripheral nerves
that travel to the limbs.
2. Which part of the neuron is typically the primary site for receiving signals from
other neurons?
A. Axon
,B. Dendrites
C. Myelin sheath
D. Axon terminal
Correct Answer: B
Expert Explanation: Dendrites are short, branching extensions that act as the
receptive region of the neuron. They receive chemical signals from the synapses of
neighboring cells. These signals are then converted into electrical graded potentials
that travel toward the cell body. The large surface area of dendrites allows a single
neuron to process thousands of inputs simultaneously. This structure is vital for the
effective integration of information within the nervous system.
3. What is the specific voltage level at which an action potential is guaranteed to occur
in a neuron?
A. Resting potential
B. Peak depolarization
C. Threshold
D. Hyperpolarization
Correct Answer: C
,Expert Explanation: Threshold is the critical membrane potential level that must
be reached to trigger an action potential. It typically occurs when the membrane
depolarizes to about -55 mV. Once this level is reached, voltage-gated sodium
channels open rapidly to initiate the impulse. This represents the ‘all-or-none’
principle of neural signaling. If the stimulus does not reach this level, no action
potential will be generated.
4. During the depolarization phase of an action potential, which ion movement is
primarily responsible for the change in membrane potential?
A. Sodium entering the cell
B. Calcium entering the cell
C. Sodium exiting the cell
D. Potassium exiting the cell
Correct Answer: A
Expert Explanation: Depolarization occurs when the neuron’s membrane potential
becomes less negative. This is caused by the rapid influx of sodium ions through
voltage-gated channels. As sodium enters the cell, it brings positive charge with it,
reversing the resting membrane polarity. This phase is the first step in propagating
an electrical impulse along the axon. Without this rapid influx, the neuron could not
transmit signals over long distances.
, 5. Which division of the peripheral nervous system is responsible for the ‘rest and
digest’ response?
A. Sympathetic division
B. Somatic motor division
C. Parasympathetic division
D. Sensory afferent division
Correct Answer: C
Expert Explanation: The parasympathetic division is a branch of the autonomic
nervous system. It promotes maintenance functions and conserves body energy
during non-stressful periods. Activities like digestion, urination, and glandular
secretion are enhanced by this division. It works in opposition to the sympathetic
division to maintain internal balance. This regulation is essential for long-term
health and metabolic efficiency.
6. Which type of neuroglial cell is responsible for forming the myelin sheath around
axons in the peripheral nervous system?
A. Astrocytes
B. Oligodendrocytes
C. Schwann cells
3 Version 1 | Questions with Correct Answers and
Expert Explanation for Each Question | Saint Paul’s
School of Nursing
1. Which component of the nervous system is primarily responsible for integrating
sensory information and initiating a motor response?
A. Peripheral Nervous System
B. Somatic Nervous System
C. Central Nervous System
D. Autonomic Nervous System
Correct Answer: C
Expert Explanation: The central nervous system consists of the brain and spinal
cord. It serves as the main integration and command center for the entire body.
Sensory input is received and processed here to determine the appropriate motor
output. This system coordinates complex activities and ensures that physiological
responses are synchronized. It is structurally separated from the peripheral nerves
that travel to the limbs.
2. Which part of the neuron is typically the primary site for receiving signals from
other neurons?
A. Axon
,B. Dendrites
C. Myelin sheath
D. Axon terminal
Correct Answer: B
Expert Explanation: Dendrites are short, branching extensions that act as the
receptive region of the neuron. They receive chemical signals from the synapses of
neighboring cells. These signals are then converted into electrical graded potentials
that travel toward the cell body. The large surface area of dendrites allows a single
neuron to process thousands of inputs simultaneously. This structure is vital for the
effective integration of information within the nervous system.
3. What is the specific voltage level at which an action potential is guaranteed to occur
in a neuron?
A. Resting potential
B. Peak depolarization
C. Threshold
D. Hyperpolarization
Correct Answer: C
,Expert Explanation: Threshold is the critical membrane potential level that must
be reached to trigger an action potential. It typically occurs when the membrane
depolarizes to about -55 mV. Once this level is reached, voltage-gated sodium
channels open rapidly to initiate the impulse. This represents the ‘all-or-none’
principle of neural signaling. If the stimulus does not reach this level, no action
potential will be generated.
4. During the depolarization phase of an action potential, which ion movement is
primarily responsible for the change in membrane potential?
A. Sodium entering the cell
B. Calcium entering the cell
C. Sodium exiting the cell
D. Potassium exiting the cell
Correct Answer: A
Expert Explanation: Depolarization occurs when the neuron’s membrane potential
becomes less negative. This is caused by the rapid influx of sodium ions through
voltage-gated channels. As sodium enters the cell, it brings positive charge with it,
reversing the resting membrane polarity. This phase is the first step in propagating
an electrical impulse along the axon. Without this rapid influx, the neuron could not
transmit signals over long distances.
, 5. Which division of the peripheral nervous system is responsible for the ‘rest and
digest’ response?
A. Sympathetic division
B. Somatic motor division
C. Parasympathetic division
D. Sensory afferent division
Correct Answer: C
Expert Explanation: The parasympathetic division is a branch of the autonomic
nervous system. It promotes maintenance functions and conserves body energy
during non-stressful periods. Activities like digestion, urination, and glandular
secretion are enhanced by this division. It works in opposition to the sympathetic
division to maintain internal balance. This regulation is essential for long-term
health and metabolic efficiency.
6. Which type of neuroglial cell is responsible for forming the myelin sheath around
axons in the peripheral nervous system?
A. Astrocytes
B. Oligodendrocytes
C. Schwann cells
