Cranial Nerves

Parosmia or anosmia

(distorted sense of smell or inability to smell) can be the result of damage to the olfactory nerve

motor (efferent) modalities

-general somatic motor (GSM): skeletal muscles -general visceral motor (GVM): smooth muscles of the gut, cardiac muscle, glands -special visceral motor (SVM): muscles of mastication, facial expression

sensory (afferent) modalities

-general somatic sensory (GSS): skin sensations -general visceral sensory (GVS): sensation from the visceral -special somatic sensory (SSS): sight, sound, balance -special visceral sensory (SVS): taste, smell

origin of cranial nerves

-nerves I and II originate form the cerebrum -nerves III-XII originate form the brainstem

the oculomotor nerve

Accommodation is modulated by

numbering of cranial nerves

numbered by their emergence from the brain front to back

vagus nerve (cardiac influence)

one responsibility of this nerve is to lower the resting heart rate

A purely afferent cranial nerve is responsible for detection of odiferous molecules. What can result from damage to this nerve?

Parosmia -The nerve is cranial nerve I, the olfactory nerve. Damage to the olfactory nerve can cause parosmia (distorted sense of smell), anosmia (inability to smell), or distorted sense of taste.

the olfactory nerve

Smell is modulated by

facial

The _________ nerve innervates the muscles of facial expression.

trigeminal

The ___________ nerve innervates the muscles of mastication.

hypoglossal

The ___________ nerve modulates voluntary movements of the tongue such as moving food. It also modulates involuntary movements like the clearing of saliva from the mouth.

optic

The light reflex is modulated by the _________ nerve, a purely afferent nerve.

vagus

The muscles of phonation are innervated by the _______ nerve

Bell's Palsy

can be the result of damage to the facial nerve

temporary facial paralysis.

can be the result of damage to the facial nerve

absence of the gag reflex.

can be the result of damage to the glossopharyngeal nerve

Double vision

can be the result of damage to the oculomotor nerve

lack of taste.

can be the result of damage to the olfactory never

nystagmus.

can be the result of damage to the vestibulocochlear nerve

vertigo

can be the result of damage to the vestibulocochlear nerve

branches of trigeminal nerve

1. Ophthalmic (V1) 2. Maxillary (V2) 3. Mandibular (V3)

Olfactory nerve

1. number: CN I 2. modality: SVS 3. function: Smell

Optic nerve

1. number: CN II 2. modality: SSS 3. function: Vision

Trochlear nerve

1. number: CN IV 2. modality: GSM 3. function: Superior oblique

glossopharyngeal nerve

1. number: CN IX 2. modality: -GSS -GVS -SVS -SVM -GVM 3. function: -sensation for posterior 1/3 of the tongue, external ear, middle ear cavity -sensation for carotid body and sinus -taste from the posterior 1/3 of the tongue -motor function of the stylopharyngess -motor function of the parotid gland

Trigeminal nerve

1. number: CN V 2. modality: -GSS -SVM 3. function: -sensation of the scalp, forehead, nose sensation -sensation of the cheeks, lower lid, nasal mucosa, upper lip, upper teeth, palate -sensation of the anterior 2/3 of the tongue, mandibular skin, lower teeth -motor innervation of the muscles of mastication

Ophthalmic branch of trigeminal nerve

1. number: CN V1 2. modality: GSS 3. function: scalp, forehead, nose sensation

Maxillary branch of trigeminal nerve

1. number: CN V2 2. modality: GSS 3. function: sensation of the cheeks, lower lid, nasal mucosa, upper lip, upper teeth, palate

Mandibular branch of trigeminal nerve

1. number: CN V3 2. modality: -GSS -SVM 3. function: -sensation of the anterior 2/3 of the tongue, mandibular skin, lower teeth -motor innervation of the muscles of mastication

abducens nerve

1. number: CN VI 2. modality: GSM 3. function: lateral rectus

facial nerve

1. number: CN VII 2. modality: -GSS -SVS -SVM -GVM 3. function: -sensation of the external ear -taste from the anterior 2/3 tongue, hard and soft palate -muscles of facial expression -lacrimal, submandibular, sublingual glands and mucus glands of mouth and nose

Vestibulocochlear nerve

1. number: CN VIII 2. modality: SSS 3. function: hearing and balance

Vagus nerve

1. number: CN X 2. modality: -GSS -GVS -SVS -GVM -SVM 3. function: -sensation for the external ear, larynx, and pharynx -sensation for the larynx, pharynx, thoracic and abdominal viscera -motor function of the cardiac, pulmonary, gastric, celiac plexuses, muscles and glands of digestive tract -motor function of the pharynx and larynx

Accessory nerve

1. number: CN XI 2. modality: GSM 3. function: motor function of the trapezius and sternicleidomastoid muscles

Hypoglossal nerve

1. number: CN XII 2. modality: GSM 3. function: motor function of tongue muscles

Oculomotor nerve

1. number:CN III 2. modality: -GSM -GVM 3. function: -extrinsic eye muscles -pupillary sphincter, ciliary muscle

Purely efferent Cranial Nerves

1. oculomotor (CN III) 2. trochlear (CN IV) 3. abducens (CN VI) 4. spinal accessory (CN XI) 5. hypoglossal (CN XII)

purely sensory (afferent) nerves

1. olfactory (CN I) 2. optic (CN II) 3. vestibulocochlear (CN VIII)

Modalities of the cranial nerves

1. sensory (afferent) modalities -general somatic sensory (GSS): skin sensations -general visceral sensory (GVS): sensation from the visceral -special somatic sensory (SSS): sight, sound, balance -special visceral sensory (SVS): taste, smell 2. motor (efferent) modalities -general somatic motor (GSM): skeletal muscles -general visceral motor (GVM): smooth muscles of the gut, cardiac muscle, glands -special visceral motor (SVM): muscles of mastication, facial expression

mix innervation nerves (sensory and motor)

1. trigeminal (CN V) 2. facial (CN VII) 3. Glossopharyngeal (IX) 4. vagus (CN X)

A purely efferent cranial nerve is involved in deliberate and involuntary movements. What is a general function of this nerve?

Clearing of saliva from the mouth -The nerve is cranial nerve XII, the hypoglossal nerve. -The hypoglossal nerve modulates voluntary movements of the tongue such as moving food. It also modulates involuntary movements like the clearing of saliva from the mouth.

olfactory

Detection of odiferous molecules is modulated by the __________ nerve, a purely afferent nerve.

A purely efferent cranial nerve affects accommodation. What can result from damage to this nerve?

Double vision The nerve is cranial nerve III, the oculomotor nerve. Fibers of the oculomotor nerve control pupil restriction, pupil dilation, and accommodation. Damage to this nerve can cause double vision and inability to coordinate movement of both eyes.

vestibulocochlear

Facilitation of balance is modulated by the __________ nerve, a purely afferent nerve.

A cranial nerve with both sensory and motor components has fibers that extend into the abdomen. What activity does this nerve modulate?

Heart rate -The nerve is cranial nerve X, the vagus nerve -The vagus nerve is responsible for lowering resting heart rate.

A cranial nerve with both sensory and motor components sends the sensation of taste from the posterior portion of the tongue. What type of muscle does this nerve innervate?

Muscle of pharynx -The nerve is cranial nerve IX, the glossopharyngeal nerve. The glossopharyngeal nerve innervates the stylopharyngeus muscle of the pharynx.

the optic nerve

Near focusing is modulated by