Neuro- Anatomy and physiology Flashcards
What does the Diencephalon become?
The thalamus
What does the telencephalon become?
the cerebral hemispheres
What does the mesencephalon become?
the midbrain
what does the metencephalon become?
The pons and the cerebellum
What does the myeencephalon become
the medulla
What is the origin of the ependymal cells, oligodendtroglia, astrocytes, and microglia?
ependymal cells, oligodendgroglia, astrocytes= neuroectoderm
microglia= mesoderm
What markers in the amniotic fluid indicate spina bifida?
AFP, AChE
What forebrain anomaly is associated with maternal diabetes?
Anencephaly
Often presents with lumbosacral myelomeningocele and paralysis below the defect
Chiari II
herniation of cerebellar tonsils and vermis through the foramen magnum
What presents with a dilated 4th ventricle and agenesis of the cerebellar vermis?
Dandy Walker
What neuronal cells stain positive for GFAP?
astrocytes
What electrolyte is in high concentration in the nodes of ranvier?
Na+
What presents as a cape like bilateral loss of pain and temperature sensation in upper extremities?
syringomyelia
What malformation is associated with syringomyelia?
Chiari I malformation
What levels are most often affected by syringomyelia?
C8-T1
What do multinucleated giant cells in the CNS indicate?
HIV-infected microglia
What is Wallerian degeneration?
Degeneration of an axon distal to the injury
What cells in the CNS have a “fried egg” appearance?
oligodendroglia
What are schwann cells derived from?
neural crest
What cell type is destroyed in Guillain-Barre?
schwann cells
What is the location and nerve associated with an acoustic neuroma?
CNVIII
internal acoustic meatus
What syndrome is associated with bilateral acoustic neuroma?
Neurofibromatosis type 2
Describe C nerve fibers. Where are the located and what do they sense?
slow, unmyelinated fibers
epidermis and some viscera
pain and temperature
Describe Ad fibers. Where are the located and what do they sense?
fast, myelinated fibers
epidermis and some viscera
pain and temperature
Describe meissner corpuscles. Where are the located and what do they sense?
large, myelinated fibers
glabrous skin
dynamic, fine/light touch; position sense
Describe pacinian corpuscles. Where are the located and what do they sense?
large, myelinated fibers
hypodermis, ligament, joint
vibration, pressure
“passionian corpuscle senses vibration)
Describe Merkel disc. Where are the located and what do they sense?
large, myelinated fibers, adapt slowly
Basal epidermal layer, hair follicle
pressure, deep static touch, position sense
What layer of the peripheral nerve is responsible for a permeability barrier and must be reattached in limb reattachment?
perineurium
Where is norepinephrine produced?
locus ceruleus (pons)
Where is dopamine produced?
ventral tegmentum and SNc (midbrain)
Where is 5-HT produced?
Raphe nucelus (pons, medulla, midbrain)
Where is ACh produced?
Basal nucleus of Meynert
Where is GABA produced?
Nucleus accumbens
What 3 neurotransmitters are altered in Huntington?
Dopamine incr
ACh, GABA decr
What 3 neurotransmitters are altered in Parkinson?
Dopamine decr
5-HT and ACh incr
What neurtransmitter is decreased in Alzheimers?
ACh
What results when the endothelial tight junctions are destroyed (eg infarction or neoplasm)?
vasogenic edema
What does the OVLT of the hypothalamus do?
Senses changes in osmolarity
What area of the brain responds to emetics?
area postrema of the hypothalamus
What nucleus of the hypothalamus makes ADH?
supraoptic nucleus
What nucleus of the hypothalamus makes oxytocin?
paraventricular nucleus
Destruction of what area of the hypothalamus results in anorexia?
Lateral area
Destruction of what area of the hypothalamus results in hyperphagia?
Ventromedial area
What is the role of the anterior hypothalamus?
Cooling, parasympathetic
A/C- anterior cooling
What is the role of the posterior hypothalamus?
Heating, sympathetic
What stage of sleep is the longest?
Stage N2 (45%)
In what stage of sleep does sleep walking, night terrors, and bedwetting occur? What type of waves are associated?
Stage N3
Delta waves- lowest freq, highest amplitude
What stage of sleep is associated with sleep spindles and K complexes?
Stage N2
What waveforms are associated with REM sleep?
Beta- highest frequency, lowest amlitude
What waveforms are associated with being awake with eyes open vs closed?
open- Beta
closed- Alpha
What are the connections of the posterior vs anterior pituitary?
posterior- neurohypophysis
anterior- adenohypohysis
What phase of sleep is associated with theta waves?
Stage N1- light sleep
What sensory modality does not relay through the hypothalamus?
olfaction
What are the inputs/ function of the VPL and VPM?
VPL- pain and temperature; pressure, touch vibration, proprioception
from spinothalmic and dorsal columns
VPM- face sensation and taste
trigeminal and gustatory pathway
What are the inputs/ function of the LGN and MGN?
LGN- vision, CNII
MGN- hearing, superiour olive and inferior colliculus of tectum
What are the inputs/ function of the VL?
motor
basal ganglia, cerebellum
What are the inputs of the cerebellum? Which peduncle?
Contralateral cortex– middle cerebellar peduncle
Ipsilateral proprioceptive– inferior cerebellar peduncle (from spinal cord)
Which side is affected for a lateral cerebellar injury?
fall towards side of injury
Presents as truncal ataxia, nystagmus, head tilting.
medial lesion of cerebellum
What makes up the striatum and lentiform?
striatum= putamen (motor) and caudate (cognitive) lentiform= putamen and globus pallidus
Intracellular eosinophilic inclusions composed of a-synuclein
Lewy bodies
What are the roles of the direct vs indirect pathways of the basal ganglia?
Direct- facilitates movement
indirect- inhibits movement
Describe the excitatory pathway of the BG?
cortical inputs– striatum—GABA release—-disinhibits thalamus via incr GPi/SNr
Describe the inhibitory pathway of the BG?
cortical inputs—striatum—disinhibits STN via GPe– stimulates GPi/SNr to inhibit thalamus
What part of the BG is affected in Parkinson’s?
substantia nigra pars compacta
What structure is affected in Hungtington? What is the repeat?
caudate nuclei atrophy, CAG (caudate loses ACh and GABA)
What is hemiballismus and what is underlying problem?
sudden flailing of 1 arm (+/- ipsilateral leg)
contralateral subthalamic nucleus
What is chorea? What area is affected?
sudden, jerky, purposeless movements Basal ganglia (Eg huntington)
What is athetosis? what area is affected?
slow writhing, esp fingers basal ganglia (eg huntington)
What is myoclonus? what conditions are usually associated?
sudden, brief, uncontrolled contractions (eg hiccups)
metabolic abnormalities- renal, liver failure
What is a resting tremor? What condition is it associated with?
uncontrolled movement of distal appendages, alleviated by intentional movment
What is intention tremor? What structure is affected?
slow, zigzag motion when pointing/extending toward a target
cerebellar dysfunction
What is the underlying cause of neuronal death in Huntington?
NMDA-R binding and glutamate toxicity
Describe the arrangement of the body in the humunculus?
Toes medial, hand/face lateral
What lobes are Broca vs Wernickes area in?
Broca- frontal
Wernicke- temporal
What presents with hyperorality, hypersexuality, disinhibited behavior?
Kluver-Bucy syndrome
What structure is affected by Kluver Bucy? What infection is it associated with?
Amygdala, HSV-1
Presents with Agrphia, acalculia, finnger agnosia, left-right disoreintation
Left parietal-temporal cortex lesion
Gerstmann syndrome
Presents with spatial neglect syndrome
Right parietal-temporal cortex lesion
Presents with confusion, ophtalmoplegia, ataxia, memory loss, confabulation, personality change
Wernicke-Korsacoff (thiamine)
Lesion that causes eyes to look away from side of lesion
paramedian pontine reticular formation
Lesion that causes eyes to look toward lesion
frontal eye fields
Acute paralysis, dysarthria, dysphagia, diplopia, loss of consciousness
central pontine myelinolysis (locked in)
What is usually the cause of central pontine myelinolysis?
osmotic forces and edema
eg overly rapid correction of hyponatremia
What areas are typically damaged from correcting Na+ too fast? (low to high vs high to low)
“From low to high, your pons will die”
“From high to low, your brain will blow” (cerebral edema/herniation)
What are deficits seen due to hypotension/ watershed zones?
upper leg/ upper arm weakness, defects in higher-order visual processing
What is the primary modulator of cerebral perfusion?
pCO2
Describe therapeutic hyperventilation
helps decr intracranial pressure in cases of acute cerebral edema (stroke, trauma); decr via vasoconstriction due to decr CO2
Stroke of this presents with contralateral paralysis of upper limb/face, contralateral loss of sensation of upper limb/face, aphagia or hemineglect
MCA stroke
Stroke of this presents with contralateral paralysis and loss of sensation of lower limb
ACA
Stroke of this presents with contralateral hemiparesis/hemiplegia
leniculostriate artery (striatum, internal capsule)
Vascular defect that presents as visual field defect
ACom saccular aneurysm
Vascular defect that presents as CN III palsy
PCom saccular aneurysm
Stroke of this presents with contralateral hemiparesis (upper and lower), contralateral loss of proprioception, tongue deviates ipsilaterally
ASA
medial medullary syndrome
Stroke of this presents with vomiting, vertigo, nystagmus; decr pain and tep of ipsilateral face and contralat body, dysphagia, hoarseness, ipsilateral Horner, ataxia
PICA lateral medullary (Wallenberg syndrome)
What are nucelus ambiguus effects and what type of stroke causes them?
hoaresness, dysphagia
PICA
Stroke of this presents with vomiting, vertigo, nystagmus, paralysis of face, decr lacrimation, salivagion, corneal reflex, decr ipsilateral hearing, ataxia
AICA
lateral pontine syndrome
Damage of the facial nucleus is specific for what type of stroke?
AICA
Stroke of this presents with contralateral hemianopia with macular sparing
PCA
Stroke of this presents with preserved consciousness and blinking, quadriplegia, loss of voluntary facial, mouth, tongue movements
basilar artery
Describe central post-stroke pain syndrome
neuropathic pain due to thalamic lesions; initially numbness and tingling, weeks to months later allodynia
Hemorrhage associated with lucid interval and rapid decline
Epidural hematoma
Hematoma that does not cross suture lines
epidural hematoma
Hematoma that crosses suture lines, can cause a midline shift, cannot cross falx/tentorium
subdural hematoma
What are the risks after 2-3 days for a subarachnoid hemmorrhage?
vasospasm (due to blood breakdown), rebleed
Rupture of a berry aneurysm causes what kind of hemorrhage?
subarachnoid hemorhage
Where are the common locations of intraparenchymal hemorrhages?
basal ganglia, internal capsule
What areas are most vulnerable to ischemic strokes?
hippocampus, neocortex, cerebellum, watershed
What are typical histologic features of strokes after 12-48 hours?
Red neurons
What are typical histologic features of strokes after 3-5 days?
macrophages
What are typical histologic features of strokes after 1-2 weeks?
Reactive gliosis + vascular proliferation
What are typical histologic features of strokes after >2 weeks?
Glial scar
What directions do the foramina of Luschka and Magendie empty?
Luschka- lateral
Magendie- medial
Presents as urinary incontinence, ataxia, cognitive dysfunction?
normal pressure hydrocephalus
What are the most common sites of vertebral disc herniation?
L4-L5, L5-S1
How many spinal nerves are there?
31
What level does the spinal cord extend to?
L1-L2
What type of motor neuron defect is indicated by fasciculations?
LMN
What spinal cord lesions are typical for MS?
mostly white matter of cervical region, random and asymmetric
What region of the spinal cord is affected by poliomyelitis?
destruction of anterior horns
What is used to treat ALS?
Riluzole (Lou Gehrig– rilouzole)
decr presynaptic glutamate release
What is and is not affected by ALS?
combined UMN and LMN
no sensory, cognitive or oculomotor deficits
What spinal cord defect presents with sparing of dorsal column sand Lissauer tract only?
complete occlusion of anterior spinal artery
Where doe occlusion of the anterior spinal artery typically occur?
upper thoracic
What spinal cord defect presents with impaired sensation and proprioception and progressive sensory loss?
Tabes dorsalis
tertiary syphilils
What spinal cord defect presents as ataxic gait, paresthesia, impaired position and vibration sense?
Vitamin B12 or E deficiency
What tracts are damaged in Vit B12 or E deficiency?
dorsal columns, lateral corticospinal, spinocerebellar
What defect presents with a floppy baby with marked hypotonia and tongue fasciculations?
Werndig-Hoffman (spinal muscular atrophy)
congenital degeneration of anterior horns of spinal cord
What presents with staggering gait, frequent falling, nysagmus, dysparthria, pes cavus, hammer toes, and hypertrophic cardiomyopathy
Friedrich ataxia
What is the most common presentation and cause of death for Friedrich ataxia?
presents as kyphoscoliosis in kids
die of hypertrophic cardiomyopathy
What is the underlying defect in Friedrich ataxia?
AR, GAA trinuc repeat on chr 9
encodes for frataxin (iron binding protein)
What dermatomal level are the nipple and umbilicus?
nipple-T4
umbilicus- T10
What dermatomal levels are the inguinal ligament and knee caps?
inguinal ligament- L1
knee cap- L4
What dermatomal levels are responsible for erection and sensation of penis and anus?
S2,S3,S4
Where does referred pain from the gallbladder and diaphragm go? why?
refer to right shoulder
phrenic nerve
What nerve roots do the biceps, triceps, patella and achilles reflexes test?
biceps- C5 triceps- C7 Patella- L4 Achilles- S1 S1, S2- buckle my shoe L3, L4- kick the door C5,C6- pick up sticks C7,C8- lay them straight
When do primitive reflexes usually disappear? What may cause them to reappear?
Disappear within 1st year
reemerge with frontal lobe lesions
What is parinaud syndrome?
paralysis of conjugate vertical gaze due to lesion of superior colliculi (eg pinealoma)
What CNs lie medially at the brain stem (3)
CNIII, VI, XII (motor- eye, tongue)
What cranial nerves are involved in the gag reflex?
Afferent: IX
Efferent: X
What cranial nerve is responsible for tongue movement?
XII (hypoglossal)
What cranial nerve provides taste for the epiglottic region?
X (vagus)
What cranial nerve raises the pharynx, larynx, and soft palate?
pharynx, larynx- IX
soft palate- X
What does the nucleus solitarius do and what cranial nerves does it supply?
visceral sensory info
VII, IX, X
What does the nucleus ambiguus do and what cranial nerves does it supply?
motor innervation of pharynx, larynx, upper esophagus
IX, X, XI
What does the dorsal motor nucleus do?
autonomic fibers to heart, lungs, upper GI
X
What nerve is typically affected by cavernous sinus syndrome?
CN VI
What nerves pass through the cavernous sinus?
CN III, IV, V1, V2, VI
What CN lesion presents as deviation of the jaw?
CNV- deviates toward lesion
What CN lesion presents as deviation of the uvula?
CNX- deviates away from lesion
What CN lesion presents as weakness of head turn and shoulder drop?
CNXI- weakness turning head contralateral, shoulder drop on side of lesion
What CN lesion presents as tongue deviation?
CNXII- tongue deviates toward side of lesion
Where are high and low pitched sounds heard?
Low frequency- apex near heicotrema (wide and flexible)
High frequency- heard at base of cochlea (thin and rigid)
Describe noise-induced damage
damage to stereociliated cells in organ of Cortii
loss of high-freq hearing
Compare conductive vs sensorineural hearing loss
Conductive- abnormal rinne (bone>air); localizes to affected ear
Sensorineural- normal rinne, localizes to unaffected ear
Compare UMN vs LMN lesion of face
UMN- contralateral, forehead spared
LMN- ipsilateral
What are the 4 muscles of mastication? What is innervation?
Close: Masseter, teMporalis, Medial pterygoid
open: lateral pterygoid
all innervated by V3
What are the typical causes of uveitis vs retinitis?
uveitis- usually systemic inflammatory disorder
retinitis- usually viral
Compare hyperopia vs myopia
hyperopia- eye too short for refractive power of cornea + lens (light focuses behind retina)
myopia- eye too long for refractive power of cornea + lens (light focuses in front of retina)
Describe presbyopia
decrease in focusing ability during accommodation due to sclerosis and decr elasticity
Presents with cloudy retina and attenuated vessels, “cherry-red” spot on fovea
central retinal artery occlusion
What is the treatment of proliferative vs nonproliferative diabetic retinopath
nonprolif- blood sugar control, macular laser
prolif- peripheral retinal photocoag, anti-VEGF
Presents as retinal hemorrhage and edema
retinal vein occlusion
Presents as eye looking down and out, ptosis, pupillary dilation, loss of accomodation
CNIII damage
Presents as eye move upward, particularly with contralateral gaze, tilt of head
CNIV damage
Presents as medially directed eye that cannot abduct
CNVI damage
Presents as enlarged blind spot and elevated optic disc with blurred margins
papilledema (incr ICP)
Presents as very painful, sudden vision loss, halos around lights, rock hard eye, frontal headache
Acute closed angle glaucoma
Presents as often asymptomatic damage to optic nerve and peripheral vision
chronic closed angle glaucoma
Describe the innervation of the ciliary muscles and epithelium?
ciliary muscle- M3 ciliary epithelium (produces aq hum)- b
Describe the innervation of the iris
Dilator- a1
Sphincter- M3
Describe blockage in closed vs open angle glaucoma
closed- blockage btwn iris and lens
open- blockage of trabecular meshwork or retinal detachment
Where is the canal of schlemm located? What does it do?
btwn cornea and sclera; collects aqueous humour from trabecular meshwork
What are causes of Upper quadrantic vs lower quandrantic anopia?
Upper: contralat temporal lesion, MCA
Lower: contralat parietal lesion, MCA
What do the meyer loop vs dorsal optic radiation supply?
Meyer loop- inferior retinal, lopp around inf horn of lateral ventricle
Dorsal optic radiation- superior retina; via internal capsule (shorter path)
Compare autonomic innervation of pupillary control
Miosis (constriction)- parasympathetic
Mydriasis (dilation)- sympathetic
What nucleus is involved in miosis?
Edinger-Westphal nucleus
What is a Marcus Gunn pupil?
Decr bilateral pupillary constriction when light is shown in affected eye
optic nerve damage or severe retinal injury
What part of the CNIII is affected by ischemia vs compression?
Ischemia (eg vascular disease)- motor output (centrally located)
Compression (eg PCom aneurysm, uncal herniation)- parasympathetic (peripherally located)- blown pupil, diminished pupillary light reflex
What presents as flashes and floaters, monocular vision loss like a “curtain drawn down”
retinal detachment, surgical emergency
What presents as visual distortion and loss of central vision
age-related macular degeneration
What is the treatment of dry vs wet macular degen?
Dry- prevent progression with multivit, antiox
wet- treat with VEGF or laser
Presents as impaired adduction of eye, nystagmus of abducting eye but normal convergence. What associated with and what structure affected?
internuclear opthalmoplegia
damage to MLF (comm betweeen VI, III)
common in MS, demyelinating
