Week 2 Flashcards
What cranial nerves are found on the pons? (4- rule of 4s)
- V - trigeminal
- VI - abducens
- VII - facial
- VIII - vestibulocochlear
What cranial nerves are found above the pons? (4- rule of 4s)
- I - olfactory
- II - optic
- III - oculomotor
- IV - trochlear
What cranial nerves are found on the medulla? (4- rule of 4s)
- IX - glossopharyngeal
- X - vagus
- XI - accessory
- XII - hypoglossal
What cranial nerve moves eyes up, down, medially; raises upper eyelid, constricts pupil, adjusts the shape of the lens of the eye?
Oculomotor (III)
What happens to eye if oculomotor nerve (III) is injured or affected?
Eye turned down and out, ptosis, pupil dilation (mydriasis), loss of accommodation
What CN moves eye medially and down?
CN IV - trochlear (controls superior oblique muscle)
What CN has the function to abduct eye (lateral rectus)
CN VI (abducens)
What CN is important for facial expression, closing eye, tears, salivation, taste?
CN VII (facial)
Olfactory - CN I
1. Central connection in brain?
- olfactory bulb
nerve itself starts in the olfactory epithelium of nasal concha
Optic - CN II
1. Central connection in brain? (2)
- Lateral Geniculate Nuclei (for vision)
- Pretectal Nuclei (mediating non-conscious behavioral responses to acute changes in light. - projects to EW nuclei)
Nerve itself starts in the retinal ganglion of the retinal bipolar cells
Vestibularcochlear - CN VIII
1. Central connection in brain for balance and VOR reflex?
but nerve starts in vestibular ganglion of semic ducts+utricle, saccule
- vestibular nuclei
nerve itself starts in the spiral ganglion of spiral organ
Vestibularcochlear - CN VIII
1. Central connection in brain for hearing?
- Cochlear nuclei
Where is the origin of the CN III (oculomotor) -> to coordinate eye movements and elevation of eyelid?
Oculomotor nucleus
Where is the origin of the CN III (oculomotor) -> to coordinate pupillary constriction and accomodation?
Edinger-Westphal nucleus
Where is the origin of the CN IV (Trochlear) -> to coordinate eye movements?
Trochlear nucleus (contralateral)
Where is the origin of the CN VI (abducens) -> to coordinate eye movements?
abducens nucleus
Where is the origin of the CN V (trigeminal) -> to coordinate mastication and dampening tympanic membrane?
Motor trigeminal nucleus
- Where is the origin of the CN V (trigeminal) -> to coordinate sensations?
- After this where does it project to?
- Trigeminal ganglion (aka gasserian)
- Principal or main spinal trigeminal nuclei
- Where is the origin of the CN V (trigeminal) -> to coordinate proprioceptive reflexes?
- After this where does it project to?
- mesencephalic trigeminal nucleus
- Motor trigeminal nucleus
reflexes like jaw reflex, lacrimal reflex, etc
Where is the origin of the CN VII (facial) -> to coordinate facial expression and dampening of stapes?
facial nucleus
Where is the origin of the CN VII (facial) -> to coordinate lacrimal glands, nasal glands, sublingual glands, submandibular glands?
superior salivatory nucleus
- Where is the origin of the CN VII (facial) -> to coordinate taste?
- After this where does it project to?
- geniculate ganglion
- Nucleus of solitary tract (solitary nucleus)
- Where is the origin of the CN IX (glossopharyngeal) -> to coordinate pharynx elevation during swallowing?
- nucleus ambiguus
- Where is the origin of the CN IX (glossopharyngeal) -> to coordinate salivation from parotid gland?
- inferior salivatory nucleus
- Where is the origin (cell bodies) of the CN IX (glossopharyngeal) -> to coordinate taste?
- Then where does it project to?
- inferior (petrosal) ganglion
- solitary nucleus (nucleus of solitary tract)
- Where is the origin (cell bodies) of the CN IX (glossopharyngeal) -> to coordinate general sensations?
- Then where does it project to?
- superior and inferior ganglia
- spinal trigeminal nucleus
- Where is the origin (cell bodies) of the CN IX (glossopharyngeal) -> to coordinate chemoreceptor and baroreceptor reflexes?
- Then where does it project to?
- inferior ganglion
- solitary nucleus
- Where is the origin (cell bodies) of the CN IX (glossopharyngeal) -> to coordinate swallowing and vocalizaiton?
- nucleus ambiguus
- Where is the origin (cell bodies) of the CN XI (accessory) -> to coordinate head and shoulder movement?
- spinal accessory nucleus in C1-C5 or C6
Peripheral distribution including:
many eye muscles (MR, SR, IR, IO), superior palpebral levator, ciliary ganglion
-> is for what CN?
CN III
The CN that has peripheral distribution to:
1. masseter, temporalis, pterygoids, mylohyoid, tensor palatini, anterior belly of digastric, tensory tympani (motor control)
8. face, anterior scalp, oral and nasal cavities, orbit (sensations)
9. muscles of mastication, periodontal membrane, TMJ (reflexes)
CN V
The CN that has peripheral distribution to:
1. Facial muscles, stylohyoid, post. belly of digastric, stapedius (motor control)
2. pterygopalatine ganglion -> lacrimal, nasal glands AND submandibular ganglion -> submandibular, sublingual glands (secretory control)
3. taste buds in anterior 2/3 of tongue (taste)
Facial nerve
The CN that has peripheral distribution to:
1. stylopharyngeus and superior pharyngeal constrictor (motor control)
2. otic ganglion -> secretion of parotid gland (secretory control)
3. posterior 1/3 of tongue (taste)
4. posterior oral canal, tonsilar region, auditory tube, middle ear (general sensations)
5. carotid bulb and sinus (chemoreceptor and baroreceptor reflexes)
- Glossopharyngeal (IX)
The CN that has peripheral distribution to:
1. pharyngeal and vocal muscles + sternomastoid and trap muscles (motor control)
- Accessory (XI)
The CN that has peripheral distribution to:
1. tongue muscles (motor control)
- hypoglossal (XII)
What CN nuclei are midline in the brainstem?
rule of 4
those that 12 can be divided by are in the middle. (ignore the ones that do not have nuclei in the brainstem - CN I and CN II)
1. CN XII, CN VI, CN IV, CN III
What are the 4 midline columns in the brainstem?
- Motor nucleus
- Motor pathway
- MLF
- Medial Lemniscus
All begin with “M”
What are the 4 lateral columns in the brainstem?
- Sympathetic
- Spinothalamic
- Sensory nucleus of CN 5
- Spinocerebellar
All start with S (“side”)
If you have injury to motor pathway (midline structure/column) what deficit do you show?
- contralateral weakness
Motor pathway (corticospinal tract)
If you have injury to medial lemniscus (midline structure/column) what deficit do you show?
- loss of contralateral proprioception/vibration
If you have injury to medial longitudinal fasciculus (midline structure/column) what deficit do you show?
- Ipsialteral internuclear ophthalmoplegia (unable to move one eye to a cetain direction - left or right)
If you have injury to motor nucleus and nerve (midline structure/column) what deficit do you show?
- ipsilateral CN motor loss (3,4,6,12 - midline CN)
If you have injury to spinocerebellar pathway (lateral structure/column) what deficit do you show?
- ipsilateral ataxia
If you have injury to spinothalamic (lateral structure/column) what deficit do you show?
- contralateral pain/temp sensory loss
If you have injury to sensory nucleus of CN5 (lateral structure/column) what deficit do you show?
- ipsilateral pain/temp loss in face
localize to lateral tract - not just the pons since its a large nerve
If you have injury to sympathetic pathway (lateral structure/column) what deficit do you show?
- Ipsilateral Horner’s Syndrome
what sx should and should not let you localize the injury to CN VIII in the pons?
- hearing loss - localize to CN VIII in the pons
- vestibular signs - these can be medulla and pons
What major artery supplies the midbrain?
PCA
What major artery supplies the pons?
- Lateral - AICA
- Medial - Basilar
What major artery supplies the medulla?
- Lateral - PICA
- Medial - ASA (anterior spinal artery)
Locked in Syndrome
1. What is it
2. what causes it
- Complete paralysis of all voluntary muscles except for the ones that control the movements of the eyes.
- Infarct affecting the base of the rostral pons OR infarct in the ventral pons affecting corticospinal tracts and corticobulbar tracts bilaterally (spinal cord and CN recieve no info from cortex
Webers syndrome
1. Can occur with an infarct to … (2)
2. Affects what region of brainstem?
- Branches of PCA and top of basilar artery
- midbrain basis
Benedikt’s syndrome
1. Can occur with an infarct to … (2)
2. Affects what region of brainstem?
- Branches of PCA and top of basilar artery
- Midbrain basis and tegmentum
AICA syndrome
1. What causes it?
2. Affects what region of brainstem?
- Stroke/infarct
- lateral pons
Medial Medullary Syndrome
1. Can occur with an infarct to …
- Paramedian branches of vertebral and spinal arteries
Wallenberg’s Syndrome
1. Can occur with an infarct to …
2. Affects what part of the brainstem
- vertebral artery
- lateral medulla
Although major a. is PICA, vertebral artery more commonly has infarct
What Meibomian glands?
- sebaceous glands in the eyelid
- Their secretions slow evaporation of tears (arrow)
What is the structure found in the space between the arrowheads?
Iris - muscle that contracts to regulate amount of light entering
- covered with melanin to give eye color and reduce light scattering
- What is the purpose of the ciliary body?
- What does it secrete?
- stretch the lens - it is attached to the lens by zonula fibers
- Secretes aqueous humor to nourish cornea/lens and help maintain eye pressure
Where is the anterior chamber of the eye found between?
- space between the cornea and the iris
What is the purpose of the canal of Schlemm?
- collects aqueous humor form anterior chamber and delivers it into the episcleral blood vessels
What structure is considered your blind spot?
optic disc bc the optic nerve forms under the optic nerve
optic disc rep start of CN II, where axons of ret. gangl. cells combine
What is the ora serrata?
The peripheral termination of the retina wehre there are no more photoreceptors
- What is the outermost layer of the retina? (on side of lens)
- Purpose:
- **Retinal pigment epithelium **
- Heavily pigment to prevent light scattering
* holds ends of rods/cones in place
* metabolic support for rods/cones
* tight junctions protect retina from blood (immune)
- What is the innermost layer of the retina? (on side of optic nerve)
- Purpose:
- inner limiting membrane
- contains basal lamina (thin ECM btwn connective tissue and basolateral side of cells) of mueller cells (principal glial cells of retina)
- Identify the layer that contains the rods and cones
- Name of the layer
- image
- Photoreceptor layer
Rods vs Cones
1. which see black and white vs color
- Rods see black and white
- Cones see color
Rods vs cones
1. What proteins are they assocaited with?
- Rods - rhodopsin
- Cones- iodopsin
What are the three types of cones and what color does each see?
- I cones -red
- M cones- green
- S cones - blue
Rods vs Cones
1. One has multiple (rods/cones) that synapse on one ganglion cell
2. One has one (rods/cones) that synpase on one ganglion cell (1:1)
- Multiple RODS synapse on one ganglion cell
- one CONE synpases on one ganglion cell
What is the fovea
A small depression in the center of the macula that contains only cones and constitutes the area of maximum visual acuity
fovea is part of macula
What is the macula
part of the retina that processes sharp, clear, straight ahead vision
- Identify the layer that contains the outer boundary of muller’s cell cytoplasm
- Name of the layer
- outer limiting membrane
“external limiting membrane”
- Identify the layer that contains the nuclei of photoreceptor cells
- Name of the layer
- outer nuclear layer
- Identify the layer that contains the processes of photoreceptor cells and bipolar cells (synapsing on bipolar cells)
- Name of the layer
- outer plexiform layer
- Identify the layer that contains nuclei of muller, bipolar, amacrine, and horizontal cells
- Name of the layer
- inner nuclear layer
- Identify the layer that contains axons of bipolar cells and the dendrites of ganglion cells (synapsing on ganglion)
- Name of the layer
- inner plexiform layer
- Identify the layer that contains ganglion cell bodies
- Name of the layer
- ganglion cell layer
- Identify the layer that contains the efferent axons from ganglion cells
- Name of the layer
- nerve fiber layer
In absence of light [hyperpolarization/depolarization] occurs in rod
depolarization - glutamate is released constantly
similar in cone