Ch 13 The Brain Cranial Neves Study Guide

What do cranial nerves represent in the nervous system?

They represent one pathway of communication from the brain to the body.

How are cranial nerves numbered?

They are numbered I to XII starting with the most anterior.

Where do most cranial nerves arise, and where do they exit?

Most arise from the base of the brain, exit through foramina, and lead to muscles or sense organs in the head and neck.

What type of nerve is CN I (Olfactory), and what is its function?

Sensory only; takes in olfactory (smell) information.

What type of nerve is CN II (Optic), and what is its function?

Sensory only; takes in visual information.

What type of nerve is CN III (Oculomotor), and what does it control?

Motor only; controls muscles opening the eyelid, and muscles controlling the lens and iris.

What type of nerve is CN IV (Trochlear), and what does it control?

Motor only; controls the superior oblique muscle for eye movement.

What type of nerve is CN V (Trigeminal), and what does it do?

Both sensory and motor; provides sensory info from facial skin, eye, nasal mucosa, sinuses, palate, teeth, gums, tongue (not taste), and floor of mouth; motor control for chewing muscles.

What type of nerve is CN VI (Abducens), and what does it control?

Motor only; controls the lateral rectus muscle of eye movement.

What type of nerve is CN VII (Facial), and what does it control?

Both sensory and motor; controls muscles of facial expression, salivary and tear glands; sensory taste from anterior tongue.

What type of nerve is CN VIII (Vestibulocochlear), and what does it do?

Sensory only; carries hearing and equilibrium information from the cochlea, semicircular ducts, and vestibule.

What type of nerve is CN IX (Glossopharyngeal), and what does it control?

Both sensory and motor; motor to salivary and tongue glands and pharynx muscles; sensory from middle and outer ear, posterior one‑third of tongue (including taste), and pharynx.

What type of nerve is CN X (Vagus), and what does it control?

Both sensory and motor; descends to organs in abdominal cavities; motor to tongue, palate, larynx, lungs, heart, liver, spleen, digestive tract, kidney, and ureter; sensory from root of tongue, pharynx, larynx, epiglottis, outer ear, thoracic and abdominal viscera.

What is unique about the origin of CN XI (Accessory)?

It originates from the cervical spinal cord.

What type of nerve is CN XI (Accessory), and what does it control?

Motor only; controls muscles of palate and pharynx, trapezius, and sternocleidomastoid.

What type of nerve is CN XII (Hypoglossal), and what does it control?

Motor only; controls muscles of the tongue.

Which cranial nerves are purely sensory?

CN I (Olfactory), CN II (Optic), CN VIII (Vestibulocochlear).

Which cranial nerves are purely motor?

CN III (Oculomotor), CN IV (Trochlear), CN VI (Abducens), CN XI (Accessory), CN XII (Hypoglossal).

Which cranial nerves are mixed (sensory + motor)?

CN V (Trigeminal), CN VII (Facial), CN IX (Glossopharyngeal), CN X (Vagus).

Which cranial nerve controls eyelid opening?

CN III (Oculomotor).

Which cranial nerve controls lens accommodation and pupil constriction?

CN III (Oculomotor).

Which cranial nerve controls the superior oblique muscle?

CN IV (Trochlear).

Which cranial nerve provides sensory information from the face?

CN V (Trigeminal).

Which cranial nerve controls the lateral rectus muscle?

CN VI (Abducens).

Which cranial nerve controls facial expression muscles?

CN VII (Facial).

Which cranial nerve provides taste from the anterior tongue?

CN VII (Facial).

Which cranial nerve carries hearing and equilibrium information?

CN VIII (Vestibulocochlear).

Which cranial nerve provides taste from the posterior one‑third of the tongue?

CN IX (Glossopharyngeal).

Which cranial nerve innervates organs in the thoracic and abdominal cavities?

CN X (Vagus).

Which cranial nerve controls trapezius and sternocleidomastoid muscles?

CN XI (Accessory).

Which cranial nerve controls tongue movement?

CN XII (Hypoglossal).

Which cranial nerve provides sensory information from the epiglottis?

CN X (Vagus).

Which cranial nerve provides sensory information from the middle and outer ear?

CN IX (Glossopharyngeal).

Which cranial nerve provides sensory information from the outer ear and viscera?

CN X (Vagus).

Which cranial nerve controls salivary glands?

CN VII (Facial) and CN IX (Glossopharyngeal).

Which cranial nerve controls tear glands?

CN VII (Facial).

Which cranial nerve controls pharynx muscles?

CN IX (Glossopharyngeal) and CN XI (Accessory).

Which cranial nerve controls palate muscles?

CN X (Vagus) and CN XI (Accessory).

Which cranial nerve controls larynx muscles?

CN X (Vagus).

Which cranial nerve controls digestive tract movement?

CN X (Vagus).

Which cranial nerve carries equilibrium information from semicircular ducts?

CN VIII (Vestibulocochlear).

Which cranial nerve carries sensory information from the nasal mucosa?

CN V (Trigeminal).

Which cranial nerve carries sensory information from the sinuses?

CN V (Trigeminal).

Which cranial nerve carries sensory information from the palate?

CN V (Trigeminal).

Which cranial nerve carries sensory information from the gums and teeth?

CN V (Trigeminal).

Which cranial nerve carries sensory information from the floor of the mouth?

CN V (Trigeminal).

Which cranial nerve carries sensory information from the root of the tongue?

CN X (Vagus).

Which cranial nerve carries sensory information from the pharynx?

CN IX (Glossopharyngeal) and CN X (Vagus).

Which cranial nerve carries sensory information from the larynx?

CN X (Vagus).

Which cranial nerve carries sensory information from the epiglottis?

CN X (Vagus).