Midterm Remediation Flashcards
Sensory; Conveys sense of smell to the brain
2. Odors - sent to limbic system (amygdala & hippocampus)
3. Damage: Blunt trauma to head (ethmoid bone), infection, during surgeries
1. Anosmia – loss of sense of smell
2. Hyposmia – decreased ability to detect smell
3. Hyperosmia – increased sensitivity to smell
4. Dysosmia – distorted sense of smell or olfactory hallucinations
CN I- Olfactory
Sensory; special somatic afferent nerve which innervates the retina of the eye and brings visual information to the brain.
2. Damage: Trauma, tumors, stroke or glaucoma
i. Damage before the optic chiasm – blindness in the eye supplied by that nerve
ii. Damage middle of the optic chiasm – lateral visual field both eye
iii. Damage to optic tract – one half of visual field lost in both
iv. Inflammation of the optic nerve causes loss of vision, usually due to swelling and/or destruction of myelin sheath
v. Bacterial infections like Lyme Disease, cat-scratch fever, syphilis
vi. Viruses – Measles, mumps and herpes`
CN II- Optic
Motor; motor nerve with somatic (voluntary) and autonomic (involuntary) efferent motor nerve. This means it has two nuclei and carries two types of efferent fibers. Somatic fibers are deep inside nerve while autonomic fibers surround the somatic fibers on the outside of the nerve. Chief motor nerve supplying the eye, adjust & coordinate eye position during movement
2. Branches:
i. Superior Branch – motor to superior rectus - elevates eyeball
1. levator palpabrae - raises upper eyelid
ii. Inferior Branch – motor to
1. inferior rectus – depresses the eyeball
2. medial rectus – adducts eyeball (toward nose)
3. inferior oblique – elevate, abducts & laterally
4. rotates eyeball
iii. Course of Nerve: Originates from the midbrain and leaves the skull through the supraorbital fissure to enter the orbit
3. Damage:
i. Third Nerve Palsy Symptoms:
1. Diplopia – double vision
2. Mydriasis – dilation of pupil
3. Upper eyelid ptosis - droopy eye lid
4. Strabismus – eye misalignment
5. Tilting of the head to compensate for vision difficulties
ii. Causes Third Nerve Palsy: Vascular disease, demyelination & tumors
CN III- Occulomotor
Motor; Supplies the one extraocular muscle, superior oblique muscle allowing eye to move down and out
2. Originates from the midbrain, decussates before leaves brainstem, only nerve leaves from posterior brainstem, only nerve originates from nucleus contralateral from structure it supplies.
3. Damage:
i. Easily damaged, congenital or trauma
ii. Trochlear Nerve Palsy – when nerve is damaged it causes eye to drift upward results head tilts to “compensate”
CN IV- Trochlear
Both; Mixed, main sensory nerve head carrying information about touch, pain, temperature and proprioception.
i. Motor control -muscles of mastication & tensor tympani (dampens loud sounds) & tensor veli palatini
1. prevents food entering nasopharynx during swallowing
2. opens eustachian tube
2. Damage:
i. Traumatic injury to face/mouth, stroke or tumor, wisdom teeth extraction
ii. Trigeminal Neuroglia –
1. Severe shooting pain or jabbing pain, sensation of electrocution.
2. Pain brought on by chewing, talking, brushing teeth, touching face
3. Pain lasts from a few seconds to several minutes, can increase in
4. duration & frequency over time
5. Pain with facial spasm
6. Pain rarely occurs while sleeping
7. Pain can affect one side of face
CN V- Trigeminal
- Motor; innervates one extraocular muscle, lateral rectus, which moves eye toward side of head, abducts eyeball
- Damage:
i. Damage causes esotropia – eye on damaged side deviates medially
ii. VI nerve palsy/Abducens Nerve Palsy
CN VI- Abducens
- Both; Controls facial movement and expression, taste ant 2/3 tongue, producing tears and noise volume (stapedius)
- Damage:
i. Damage to a given branch will impact the function of that branch
ii. Other Common facial nerve disorders: Bell’s Palsy, Lyme disease, stroke, tumors (parotid, ear & skull base), trauma to nerve or viral infections
CN VII- Facial
- Sensory; conveys sound and equilibrium information from inner ear to the brain.
- Damage:
i. Vestibular Neuritis – swelling of nerve. - Acute phase – sudden severe symptoms 1 week
a. Sudden & severe vertigo (spinning sensation)
b. Intense dizziness (feeling lightheaded or unsteady)
c. Severe balance issues
d. Nausea & vomiting
e. Severe motion sensitivity
f. Nystagmus – cannot control eye movement - Chronic phase – milder symptoms last from few weeks or months
- Vestibular Neuritis – swelling of nerve.
- Chronic phase – milder symptoms last from few weeks or months
- Causes: viral infections (chickenpox or viral hepatitis), flu, COVID 19, Herpes simplex virus 1
CN VIII- Vestibulocochlear
- Both;
i. Sensory (touch, pain and temperature)to posterior 1/3 tongue upper pharynx, tonsils, outer ear, eardrum & eustachian tube.
ii. carotid body & carotid sinus – detects oxygen, carbon dioxide, ph levels in blood and blood pressure changes.
iii. Taste from posterior 1/3 of tongue
iv. Motor to stylopharyngeus muscle and parotid gland - Damage:
i. Nerve lesions – difficulty in swallowing, loss of taste posterior 1/3 of tongue, impaired sensation back of tongue, palate & pharynx, diminished or absent gag reflex
ii. Causes – Tumors, infections, muscle swelling onto branches
CN IX- Glossopharyngeal
- Both; gland secretion, peristalsis, phonation, taste, visceral and general sensation of the head, thorax and abdomen.
- Damage:
i. Gastroparesis – damage to vagus nerve stops food from entering your stomach
ii. Achalasia – loss lower esophageal motility
iii. Vasovagal Syncope – vagus nerve to heart “overreacts” blood pressure drops quickly causing dizziness or fainting
iv. Causes – surgical, trauma, Stroke, diabetes, infections, auto-immune disorders
CN X- Vagus
- Motor; Supplies sternocleidomastoid (SCM) and trapezius muscles; rotation of head away from side contraction SCM, tilt head toward contracting SCM, flexion of neck by both SCM & shoulder elevation by trapezius
- Damage: Prone to injury due to long and superficial nature
- Causes – trauma, surgery (especially for lymph nodes or jugular vein)
CN XI- Accessory/Spinal Accessory
- Motor; Motor to tongue to control movements for eating and speaking. Supplies intrinsic muscles and three extrinsic muscles of tongue.
- Damage:
i. Nerve injury can cause dysarthria, dysphagia and possible airway protection reduction (if bilateral)
ii. Causes –tumor, infection and trauma – surgical/blunt force, stroke, cancer, ALS - Bilateral damages are but can occur with radiation damage
iii. Unilateral impairment often unremarkable due to compensation. Bilateral damage to hypoglossal impacts speech & swallowing
Hypoglossal
