Cranial Nerves

75 practice flashcards covering the key facts about cranial nerves I–XII, their functions, nuclei locations, and autonomic components.

Which cranial nerve originates in the nasal epithelium and transmits the sense of smell?

Cranial Nerve I (Olfactory nerve).

What functional type is CN I?

Special sensory only (smell).

What are the three main components of CN I's olfactory pathway mentioned in the notes?

Olfactory bulb, olfactory tract, and uncus (1° olfactory cortex).

Which cranial nerve transmits the sense of sight?

Cranial Nerve II (Optic nerve).

What are the main components of CN II's pathway as described?

Optic nerve, optic chiasm, and optic tract.

Which cranial nerve is the only one that is part of the CNS?

Optic nerve (CN II).

Where are the nuclei for CN III through CN XII located?

In the brainstem.

CN I is classified as which functional type?

Special sensory only.

CN II is classified as which functional type?

Special sensory only (vision).

CN III has which two functional components?

Somatic motor and parasympathetic.

Which muscles are innervated by CN III for somatic motor?

Levator palpebrae superioris, superior rectus, medial rectus, inferior rectus, and inferior oblique.

What parasympathetic actions does CN III provide?

Pupil constriction (sphincter pupillae) and lens accommodation (ciliary muscle).

CN IV: which nucleus and which muscle does it innervate?

Nucleus in the midbrain; somatic motor to the superior oblique.

CN V is composed of how many divisions and which is purely sensory?

Three divisions (V1, V2, V3); V1 is purely sensory.

Which division of CN V is purely sensory and supplies the cornea and forehead?

V1 (ophthalmic division).

V1 provides somatic sensation from which regions?

Skin of the anterior scalp, forehead, superior eyelid, dorsum of nose; cornea; portions of nasal mucosa and paranasal sinuses; portions of dura mater.

Which division of CN V supplies sensation to the cheek and upper lip?

V2 (maxillary division).

V2 also carries sensation from which teeth and dura?

Maxillary teeth and portions of dura mater (plus nasal mucosa and sinuses).

V3 is mixed; what does it innervate motor-wise?

Muscles of mastication and other small head/neck muscles.

V3 provides somatic sensation from where?

Skin over jaw, lower lip; mandibular teeth; anterior 2/3 of tongue (texture and temperature).

Where are the trigeminal sensory and motor nuclei located?

In the pons.

Which cranial nerve innervates the lateral rectus muscle?

CN VI (Abducens).

Where is the CN VI nucleus located?

Pons.

CN VII has which functional components?

Special sensory, somatic motor, and parasympathetic.

CN VII motor innervation supplies which muscles?

Muscles of facial expression.

CN VII parasympathetic targets include which glands?

Lacrimal gland; submandibular and sublingual glands.

What mnemonic is used to remember CN VII parasympathetic targets?

Spits & cries.

CN VII's special sensory function is taste from which part of the tongue?

Anterior 2/3 of the tongue.

CN VIII is responsible for which senses?

Hearing and balance (equilibrium).

Where is CN VIII's sensory nucleus located?

In the pons; originates from inner ear structures.

CN IX's specialties include taste from which tongue region?

Posterior 1/3 of the tongue.

CN IX has somatic sensory from where?

Posterior 1/3 of tongue and part of pharynx.

CN IX's somatic motor innervation targets which muscle group?

One small muscle in the pharynx (stylopharyngeus).

CN IX's visceral sensory components monitor which receptors?

Carotid body (to monitor O2/CO2) and carotid sinus (to monitor blood pressure).

CN IX's parasympathetic function targets which gland?

Parotid gland.

CN X has how many functional categories?

Four: somatic sensory, somatic motor, visceral sensory, and parasympathetic.

CN X somatic motor targets include which structures?

Muscles in soft palate, pharynx, and larynx.

CN X visceral sensory inputs come from which organs?

Lungs, trachea/bronchi, heart, GI organs, pancreas.

CN X parasympathetic actions include what effects on heart, respiration, airways, and digestion?

Decrease heart rate, decrease respiratory rate, constrict airways, increase digestion.

Where are CN X's nuclei located?

Medulla.

CN XI's nuclei are located where?

Medulla and cervical spinal cord.

CN XI innervates which muscles?

Trapezius and sternocleidomastoid.

What actions does the trapezius perform?

Elevate, retract, depress, and rotate the scapula.

What actions does the sternocleidomastoid perform?

Flex the neck, lateral flexion, and rotate the head to the contralateral side.

Where is CN XII's nucleus located?

Medulla.

CN XII innervates which tongue muscles?

Extrinsic and intrinsic muscles of the tongue.

Which division of CN V carries motor fibers?

V3 (mandibular division) – mixed; contains motor fibers for mastication.

Which cranial nerve carries parasympathetic output to the lacrimal gland?

CN VII.

Which cranial nerve supplies taste from anterior 2/3 of the tongue?

CN VII.

Which cranial nerve supplies taste from posterior 1/3 of the tongue?

CN IX.

Which cranial nerve is responsible for hearing and balance and has a sensory nucleus in the pons?

CN VIII.

Which cranial nerve carries parasympathetic output to submandibular and sublingual glands?

CN VII.

Which cranial nerve carries taste from anterior tongue and innervates facial expression muscles?

CN VII.

Which cranial nerve provides somatic sensation from cornea and nasal mucosa?

CN V1 (ophthalmic division of Trigeminal nerve).

Which division of CN V carries sensation from the maxillary teeth and palate?

V2 (maxillary division).

Which division of CN V carries sensation from the anterior two-thirds of the tongue and motor to mastication?

V3 (mandibular division).

Which cranial nerve innervates the levator palpebrae superioris to elevate the eyelid?

CN III (Oculomotor nerve).

Which cranial nerve provides pupil constriction and lens accommodation?

CN III.

Which cranial nerve innervates the lateral rectus muscle?

CN VI.

Which cranial nerve innervates the superior oblique muscle?

CN IV.

Which cranial nerve is involved in parasympathetic control of the lacrimal and salivary glands?

CN VII.

Which cranial nerve controls the muscles of facial expression?

CN VII.

Which cranial nerve controls the tongue muscles for movement (intrinsic and extrinsic)?

CN XII.

Which cranial nerve is involved in swallowing via pharyngeal muscles and voice box?

CN X.

Which cranial nerve provides parasympathetic input to the heart, lungs, and GI tract?

CN X (Vagus nerve).

Which cranial nerve has a nucleus in both the medulla and cervical spinal cord?

CN XI (Accessory nerve).