BIOL251: Human Anatomy & Physiology I w/Lab
Module 7 Exam Review: Peripheral Nervous System,
Reflex Activity, and the PNS
1. A patient presents with anosmia (inability to smell) following a head injury. Which
cranial nerve is most likely damaged?
• A) Oculomotor (CN III)
• B) Optic (CN II)
• C) Trigeminal (CN V)
• D) Olfactory (CN I)
Answer: D) Olfactory (CN I)
Rationale: The Olfactory nerve (CN I) is responsible for the sense of smell. It is particularly
vulnerable to shearing injuries during head trauma because it passes through the cribriform
plate of the ethmoid bone. Damage here results in anosmia .
2. A patient complains of double vision (diplopia) and an inability to move the eye
downward. Which nerve is likely affected?
• A) Trochlear (CN IV)
• B) Abducens (CN VI)
• C) Oculomotor (CN III)
• D) Optic (CN II)
Answer: A) Trochlear (CN IV)
Rationale: The Trochlear nerve (CN IV) innervates the superior oblique muscle, which is
responsible for depressing and intorting the eye. Damage to CN IV causes difficulty looking
downward (especially when the eye is adducted) and often results in vertical diplopia.
3. During a physical exam, a doctor asks a patient to shrug their shoulders against
resistance. Which cranial nerve is being tested?
• A) Hypoglossal (CN XII)
, • B) Accessory (CN XI)
• C) Vagus (CN X)
• D) Glossopharyngeal (CN IX)
Answer: B) Accessory (CN XI)
Rationale: The Accessory nerve (CN XI) is a motor nerve that controls the
sternocleidomastoid and trapezius muscles. Shrugging the shoulders tests the strength of
the trapezius muscle, thereby assessing the integrity of CN XI.
4. Which of the following cranial nerves is responsible for transmitting sensory
information related to touch, pain, and temperature from the face?
• A) Facial (CN VII)
• B) Glossopharyngeal (CN IX)
• C) Trigeminal (CN V)
• D) Vagus (CN X)
Answer: C) Trigeminal (CN V)
Rationale: The Trigeminal nerve (CN V) is the primary sensory nerve of the face. It has three
divisions (Ophthalmic V1, Maxillary V2, Mandibular V3) that relay sensation from the face to
the brain. While CN VII does taste, it does not handle general sensation of the face.
5. A patient has difficulty swallowing and speaking (dysphagia and dysphonia), and their
uvula deviates to the left when they say "ah." Which nerve is damaged?
• A) Right Hypoglossal (CN XII)
• B) Left Vagus (CN X)
• C) Right Vagus (CN X)
• D) Left Glossopharyngeal (CN IX)
Answer: C) Right Vagus (CN X)
Rationale: The Vagus nerve (CN X) innervates the muscles of the pharynx and larynx. It also
provides motor innervation to the soft palate (except the tensor veli palatini). If the right
vagus is damaged, the right side of the soft palate sags; when the patient says "ah," the
uvula is pulled toward the intact side (left).
, 6. Which of the following is NOT a function of the Facial nerve (CN VII)?
• A) Taste from the anterior 2/3 of the tongue
• B) Motor control of muscles of facial expression
• C) Motor control of the masseter muscle for chewing
• D) Parasympathetic stimulation of salivary glands
Answer: C) Motor control of the masseter muscle for chewing
Rationale: Motor control for chewing (mastication) is a function of the Trigeminal nerve (CN
V), specifically the mandibular division (V3). The Facial nerve (CN VII) controls muscles of
facial expression, taste from the anterior tongue, and parasympathetic innervation to the
submandibular and sublingual glands.
Section 2: Nerve Plexuses & Peripheral Nerves
7. The phrenic nerve (C3-C5) is essential for life because it innervates the:
• A) Intercostal muscles
• B) Diaphragm
• C) Trapezius muscle
• D) Deltoid muscle
Answer: B) Diaphragm
Rationale: The phrenic nerve arises from the cervical plexus (C3-C5) and provides the sole
motor innervation to the diaphragm. Contraction of the diaphragm is the primary
mechanism for inspiration. Injury to this nerve would cause paralysis of the diaphragm and
respiratory failure.
8. A patient presents with "foot drop" (inability to dorsiflex the foot) and loss of sensation
on the anterior leg. Which nerve is likely injured?
• A) Sciatic nerve
• B) Tibial nerve
• C) Common fibular (peroneal) nerve
• D) Femoral nerve
Answer: C) Common fibular (peroneal) nerve
Rationale: The common fibular (peroneal) nerve is a branch of the sciatic nerve. It
Module 7 Exam Review: Peripheral Nervous System,
Reflex Activity, and the PNS
1. A patient presents with anosmia (inability to smell) following a head injury. Which
cranial nerve is most likely damaged?
• A) Oculomotor (CN III)
• B) Optic (CN II)
• C) Trigeminal (CN V)
• D) Olfactory (CN I)
Answer: D) Olfactory (CN I)
Rationale: The Olfactory nerve (CN I) is responsible for the sense of smell. It is particularly
vulnerable to shearing injuries during head trauma because it passes through the cribriform
plate of the ethmoid bone. Damage here results in anosmia .
2. A patient complains of double vision (diplopia) and an inability to move the eye
downward. Which nerve is likely affected?
• A) Trochlear (CN IV)
• B) Abducens (CN VI)
• C) Oculomotor (CN III)
• D) Optic (CN II)
Answer: A) Trochlear (CN IV)
Rationale: The Trochlear nerve (CN IV) innervates the superior oblique muscle, which is
responsible for depressing and intorting the eye. Damage to CN IV causes difficulty looking
downward (especially when the eye is adducted) and often results in vertical diplopia.
3. During a physical exam, a doctor asks a patient to shrug their shoulders against
resistance. Which cranial nerve is being tested?
• A) Hypoglossal (CN XII)
, • B) Accessory (CN XI)
• C) Vagus (CN X)
• D) Glossopharyngeal (CN IX)
Answer: B) Accessory (CN XI)
Rationale: The Accessory nerve (CN XI) is a motor nerve that controls the
sternocleidomastoid and trapezius muscles. Shrugging the shoulders tests the strength of
the trapezius muscle, thereby assessing the integrity of CN XI.
4. Which of the following cranial nerves is responsible for transmitting sensory
information related to touch, pain, and temperature from the face?
• A) Facial (CN VII)
• B) Glossopharyngeal (CN IX)
• C) Trigeminal (CN V)
• D) Vagus (CN X)
Answer: C) Trigeminal (CN V)
Rationale: The Trigeminal nerve (CN V) is the primary sensory nerve of the face. It has three
divisions (Ophthalmic V1, Maxillary V2, Mandibular V3) that relay sensation from the face to
the brain. While CN VII does taste, it does not handle general sensation of the face.
5. A patient has difficulty swallowing and speaking (dysphagia and dysphonia), and their
uvula deviates to the left when they say "ah." Which nerve is damaged?
• A) Right Hypoglossal (CN XII)
• B) Left Vagus (CN X)
• C) Right Vagus (CN X)
• D) Left Glossopharyngeal (CN IX)
Answer: C) Right Vagus (CN X)
Rationale: The Vagus nerve (CN X) innervates the muscles of the pharynx and larynx. It also
provides motor innervation to the soft palate (except the tensor veli palatini). If the right
vagus is damaged, the right side of the soft palate sags; when the patient says "ah," the
uvula is pulled toward the intact side (left).
, 6. Which of the following is NOT a function of the Facial nerve (CN VII)?
• A) Taste from the anterior 2/3 of the tongue
• B) Motor control of muscles of facial expression
• C) Motor control of the masseter muscle for chewing
• D) Parasympathetic stimulation of salivary glands
Answer: C) Motor control of the masseter muscle for chewing
Rationale: Motor control for chewing (mastication) is a function of the Trigeminal nerve (CN
V), specifically the mandibular division (V3). The Facial nerve (CN VII) controls muscles of
facial expression, taste from the anterior tongue, and parasympathetic innervation to the
submandibular and sublingual glands.
Section 2: Nerve Plexuses & Peripheral Nerves
7. The phrenic nerve (C3-C5) is essential for life because it innervates the:
• A) Intercostal muscles
• B) Diaphragm
• C) Trapezius muscle
• D) Deltoid muscle
Answer: B) Diaphragm
Rationale: The phrenic nerve arises from the cervical plexus (C3-C5) and provides the sole
motor innervation to the diaphragm. Contraction of the diaphragm is the primary
mechanism for inspiration. Injury to this nerve would cause paralysis of the diaphragm and
respiratory failure.
8. A patient presents with "foot drop" (inability to dorsiflex the foot) and loss of sensation
on the anterior leg. Which nerve is likely injured?
• A) Sciatic nerve
• B) Tibial nerve
• C) Common fibular (peroneal) nerve
• D) Femoral nerve
Answer: C) Common fibular (peroneal) nerve
Rationale: The common fibular (peroneal) nerve is a branch of the sciatic nerve. It
