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
