NBME Neuro Flashcards
Alar plate
Posterior horn, sensory area of spinal cord. also it is the lateral part of the brainstem.
Basal plate
Anterior horn, motor area of spinal cord, also it is the medial part of the brainstem
Telencephalon
Cerebral hemispheres
Diencephalon
Thalamus
Mesencephalon
Midbrain
Metencephalon
Pons and Cerebellum
Myencephalon
Medulla
When do neuropores fuse?
4th week of pregnancy
Spina bifida occulta
Failure of bony spinal canal to close. there is no herniation–tuft of hair.
Meningocele
Meninges herniate through spinal canal defect
Meningomyelocele
Meninges and spinal cord herniate through spinal canal defect
Holoprosencephaly
Failure of right and left hemispheres to separate. usually occurs during weeks 5-6. may be related to SHH. moderate forms are cleft lip and palate. severe is cyclopia
Syringomyelia
Enlargement of central canal of spinal cord forming a syrinx. crossing fibers of spinothalamic tract are damaged first-ussualy associated with cape like loss of pain and temp on bilateral shoulders. later on can be bilateral weakness.
Tongue innervation
Taste: Anterior 2/3 = (VII); Posterior 1/3 = (IX, X); Epiglottis = (X)
Sensory: Anterior 2/3 = (V) Posteror 1/3 = (IX, X); Epiglottis = (X)
Microglia
Made from mesoderm
Act as macrophages in the brain
Can get infected by HIV
Astrocytes
Made from neuroectoderm.
Physical support and repair (forms glial scar)
Metabolize K, removal of excess neurotransmitter, and maintenance blood brain barrier.
Marker is GFAP.
Myelin
Central: oligodendrocytes
Peripheral: schwann cells
Increase conduction velocity (saltatory conduction)
Multiple Sclerosis
Destroys Oligodendrocytes (CNS myelin). random asymmetric lesions, due to (autoimmune) demyelination. scanning speech, intention tremor, and nystagmus. Cause internuclear opthalmoplegia. most often affects women in 20s and 30s. Oligoclonal bands are diagnostic in CSF. β-interferon used to treat.
Guillan Barre
Auto-immune disease that destroys Schwann cells (PNS myelin). symmetric ascending muscle weakness beginning in lower limbs.
C Pain fibers
Are slow, unmyelinated fibers for pain and temperature.
Αδ Pain fibers
Are fast, myelinated fibers for pain and temperature.
Meissners corpuscles
Large myelinated fibers for light/fine touch (adapt quickly)
Pacinian corpuscles
Large myelinated fibers for deep touch/vibration
Perineurium
Surrounds a fascicle of nerves and must be sewed back together when a attaching a severed limb.
Epi-outer
Peri-middle
Endo-inside
Locus Ceruleus
Makes NE. Located in the pons. Increase will cause anxiety, decrease will cause depression.
Dopamine
Made in Ventral tegmentum and substantia nigra. Increase leads to schizophrenia. Decrease leads to Parkinsons. Decrease also leads to depression
5-HT (serotonin)
Made in Raphe nucleus (pons). Decrease leads to depression. Decrease also leads to anxiety.
Ach
Made in Basal nucleus of Meynert. Decrease leads to Alzheimers. Decrease leads to Huntingtons. It is increased in burst during REM sleep
GABA
Made in Nucleus Accumbens (pleasure center). Decrease leads to anxiety. Decrease leads to Huntingtons.
What forms the Blood brain barrier
Tight Jxns b/w nonfenestrated capillary endothelial cells, basement membrane, and astrocyte foot process. It is absent at circumventricular organs.
Area postrema
Has no blood brain barrier–vomiting center.
Lateral hypothalamus
Hunger. destruction will lead to failure to thrive (anorexia)
Medial hypothalamus
Satiety (fullness). Destruction will lead to over eating.
Anterior hypothalamus
Controls cooling, parasympathetics, reproduction/sex, and drinking… A/C (air conditioning)
Lesion can cause hyperthermia
Posterior hypothalamus
Controls heating and sympathetics.
Poikilotherm
Damage to the posterior hypothalamus… makes you cold blooded. like a snake.
Poikilothermia is cause by a lesions to both anterior (cooling/parasympathetics) and posterior (heating/sympathetics) hypothalamus
VPL of thalamus
Receives sensory info from spinothalamics and DCML for Pain/temp and touch for body. Sends info to the primary somatosensory cortex of brain
VPM of thalamus
Receives sensory info from trigeminal and gustatory pathway for face sensation and taste. Sends info to the primary somatosensory cortex of the brain
LGN
Receives info from CN II and is used for VISION. Sends info to the calcarine sulcus
MGN
Receives info from Superior olive and inferior colliculus of tectum for HEARING. sends info to temporal lobe
VL
Receives info from basal ganglia for motor movement initiation and goes to the motor cortex.
Limbic system
Structures include the hippocampus, amygdala, fornix, mammillary bodies, and cingulate gyrus. Responsible for Feeding, Fleeing, Feeling, and Fuc-king. Involved in emotion, long term memory, olfaction, behavior modulation and ANS fxn.
Cerebellum
Aids in coordination and balance. Sends info to the contralateral cortex, so eventually it effect the ipsilateral body. Output fibers are purkinje fibers send to deep nuclei then these have fibers that go to cortex
Deep nuclei of Cerebellum
Fastigial, Globose, Emboliform, and Dentate.
(F=GED). Medial to lateral.
Parkinson’s disease
Lewy bodies composed of α-synuclein. loss of dopamine neurons of the substantia nigra. Tremors at rest, cogwheel rigidity, akinesia, and postural instability, shuffling gait. Causes dementia.
Huntington’s disease
Autosomal dominant (CAG repeats 40+). characterized by chorea, agression, depression, and dementia. glutamate toxicity. atrophy of the caudate, so no caudate visible on imaging.
Hemiballismus
Sudden wild flinging of limbs due to damage of subthalamic nucleus and effects the contralateral side
Intention tremor
Slow, zigzag motion when pointing/extending toward a target due to damage of the cerebellum (dentate nucleus)
Arcuate fasciculus
Connects Brocas area to Wernickes area.
Kluver Bucy syndrom
Bilateral damage to Amygdala and is associated with hyper-sexulaity and disinhibited behavior. Associated with HSV-1.
Damage to frontal lobe
Disinhibition and deficits in concentration, change in judgement (almost like a different person). reemergence of primitive reflexes (moro, rooting, sucking, palmar, plantar, galant).
Damage to right parietal lobe
Hemispatial neglect syndrome. Neglects the contralateral side of the body.
Damage to RAS
Reduced levels of wake fullness. Can even cause narcolepsy and coma if it is too far down regulated.
Damage to Mamillary bodies
Often seen with Wernickes korsakoff syndrom. Confusion opthalmoplegia, ataxia, memory loss with confabulation and personality changes. Associated with low B1 (thiamine) and alcoholics.
Damage to Hippocampus
Will result in anterograde amnesia… unable to form new memories
Brocas aphasia
Can understand but cant speak. Damage to Brocas area
Wernickes aphasia
Can’t understand but can speak… speaks gibberish. Damage to Wernickes area
Global aphasia
Can’t speak or understand. Both Wernicke’s and Broca’s areas are affected
Conduction aphasia
Poor repetition but fluent speech. intact comprehension. Can be caused by damage to Arcuate Fasciculus (superior temporal lobe and/or left supramarginal gyrus). Can’t repeat “no, ifs, ands, or, buts.”
Wallenbergs syndrom
PICA artery is blocked. Patient has nystagmus, vertigo, dec pain and temp, dyspahgia, and hoarsness, dec gag reflex, ipsilateral horners.
CN blood supply
I, II--Anterior cerebral artery III, IV--Posterior cerebral artery V, VI, VII--AICA VIII, IX, X--PICA XI, XII--Anterior spinal artery
Epidural Hematoma
Rupture of Middle meningeal artery due to fracture of pterion. Can cause CN III palsy.
Subdural Hematoma
Rupture of bridging veins. Slow venous bleeding. seen in elderly and alcoholics (b/c of many falls). crescent shaped on imaging
Subarachnoid hemorrhage
Rupture of an aneurysm (berry aneurysm Ant communicating artery) seen in Marfans and Ehlers Danlos. Rapid time course, causes worst headaches of their lives.
Flow of CSF
Made in Lateral and third ventricles by choroid plexus. Lateral ventricle ->foramen of monro->3rd ventricle->cerebral aqueduct->4th ventricle->foramin of lushcka and foramen of magendie. Reabsorbed in Arachnoid granulations.
End of spinal cord
L1/L2 in adult can do lumbar puncture L3-L5
Dorsal columns
Fasciculus cuneatus (upper body) and Fasciculus gracilis (lower body). Decussates in caudal medulla. For pressure, vibration, touch, and proprioception. Goes to VPL
Lateral corticospinal tract
Decussates in caudal medulla. Used for voluntary motor from shoulders down.
Anterior spinothalamic tract
Decussates 2 levels up in the spinal cord. Used for Crude touch and pressure. Goes to VPL
Lateral spinothalamic tract
Decussates 2 levels up in spinal cord. Used for pain and temp. Goes to VPL
UMN lesion
Hyper-reflexia, inc tone, positive babinski, spastic paralysis, positive clasp knive.
LMN lesion
Atrophy, fasciculations, hypo reflexia, dec tone, flaccid paralysis.
Poliomyelitis
LMN lesion, destruction of anterior horn cells. flaccid paralysis. Caused by poliovirus.
Amyotrophic lateral sclerosis (ALS)
Combined UMN and LMN lesions. No loss of sensory, cognition or oculomotor deficits. Defect in superoxide dismutase 1. Tongue fasciculations with eventual atrophy. Fatal b/c effects breathing muscles. Disease is due to degeneration of nerve axon… not myelin
Complete occlusion of Anterior spinal artery
Spares dorsal columns and lissauers tract. Motor problems.
Tabes Dorsalis (tertiary syphilis)
Demyelination of dorsal columns and roots. Impaired sensation and proprioception. with progressive ataxia. argyll robertson pupils (prostitutes pupils) accomodate but dont react to light. Absence of DTRs and Positive Rombergs test.
B12 deficiency causes what in spine
Demyelination of dorsal columns, lateral corticospinal tracts and spinocerebellar tracts. leading to ataxic gait, paresthesia, and impaired vibration and position sense.
Friedreichs ataxia
Autosomal recessive tri-nucleotide repeat disorder (GAA) in gene that codes for frataxin. staggering gait, frequent falling, nystagmus, dysarthria, hammer toes, and hypertrophic cardiomyopathy.
Brown-Sequard syndrome
Lesion to half of spinal cord will cause ipsilateral weakness and loss of vibration, joint and position sensation, and proprioception but contralateral loss of pain and temperature. ipsilateral loss of all sensation at the level of the lesion due to dermatome loss.
Horners syndrome
Damage to sympathetics. Will cause Ptosis, Miosis, and Anhidrosis of the face
T4 dermatome
Nipples
T7 dermatome
Xiphoid process
T10 dermatome
Umbilicus
L1 dermatome
Inguinal canal
L4 dermatome
Knees
S2, S3, S4 dermatomes
Penis
Biceps reflex
C5 nerve root
C6
Triceps reflex
C7 nerve root
C8
Patella reflex
L3
L4 nerve root
Achilles Reflex
S1 nerve root
S2
Parinaud’s syndrome
Paralysis of conjugate vertical gaze due to lesion in superior colliculi
Corneal reflex
Afferent V (spinal trigeminal nucleus)
Efferent VII (facial motor nucleus{)Lacrimation reflex
Afferent V (spinal trigeminal nucleus) Efferent VII (superior salivatory nucleus)
Jaw Jerk reflex
Afferent V (mesencephalic nucleus) Efferent V (motor trigeminal nucleus)
Pupillary reflex
Afferent II
Efferent III
II->pretectal nuclei->edinger westphall nuclei->bilateral III to cause both pupils to constrict.
Gag reflex
Afferent IX (solitary nucleus) Efferent X (nucleus ambiguus)
Nucleus Solitarius
Visceral Sensory Information. Taste.
VII, IX, X
Nucleus Ambiguous
Motor innervation of pharynx, larynx, trachea, SCM and Trapezius (IX, X, XI).
Dorsal motor nucleus of vagus
Goes to heart, lungs, and upper GI (X)
CN X lesion
Uvula deviates away from side of lesion
CN XI lesion
Weakness in turning head away from lesion and shoulder drop on side of lesion
CN XII lesion
Stick out tongue and it deviates toward the lesion.
Weber test
If senurineural loss, it will lateralize to good ear
If conductive loss it will lateralize to bad ear
Rinne test
If conductive loss Bone > Air
If normal Air > Bone
Corticobulbar lesion
Will result in contralateral lower face drooping but forehead will be normal.
Facial nerve palsy
Bells Palsy. Ipsilateral facial paralysis. Because of facial motor nucleus damage.
Mastication muscles
Innervated by CN V.
Close Jaw: Massester, temporalis and medial pterygoid
Open Jaw: lateral pterygoid
Hyperopia
Small eye. image converges behind retina. HFX. Far sighted, Convex lens corrects
Myopia
Big eye. Image converges in front of retina. MNV. nearsightedness, Concave lens corrects
presbyopia
Decrease in elasticity of lens. Can’t accommodate as well. needs reading glasses.
Aqueous humor pathway
Made in the Ciliary processes->posterior chamber->pupil->Anterior chamber->Trabecular network->canal of Schlemm->episcleral veins.
Glaucoma
Caused by increased ocular pressure due to less aqueous humor being absorbed in canal of Schlemm. peripheral then central vision loss. Optic disc atrophy.
Cataract
When the lens becomes cloudy and needs to be replaced.
Papilledma
Increased inter cranial pressure puts pressure on optic nerve decreasing vision.
Miosis
Parasympathetics Constrict pupil
SD in PC
Midriasis
Sympathetics dilate pupil
SD in PC
Marcus gun pupil
When there is a damage to the Afferent limb of pupillary light reflex.
Right anopia
Damage to right optic nerve
Bitemporal hemianopia
Damage to optic chiasm (caused by pituitary tumor commonly)
Left Homonymous hemianopia
Damage to the right optic tract
Left upper quadrant anopia
Damage to the right Meyers loop… Temporal lobe
Left lower quadrant anopia
Damage to the right dorsal optic radiation through the Parietal lobe
Left hemianopia with macular sparing
PCA infarct.
Central scotoma
Macular degeneration
Medial longitudinal fasciculus (MLF)
Pair of tracts that allows VI to communicate with III and gives us conjugate eye movements (in horizontal direction). When it is damaged it is called internuclear opthalmoplegia. Highly myelinated–so damaged when patient has MS
Alzheimers disease
Genes: APP (21–Gama and Beta secretase cuase AB amyloid to accumulate), Presenilin-1 (14), Presenlin-2 (1).
ApoE2-protective, ApoE3-normal, ApoE4-Alzheimer’s (19).
Decrease in ACh. Wide sulci b/c of cortical atrophy.
Extracelluar AB amyloid plaques and intracellular Neurofibrillary tangles are found (abnormally phosphorylated Tau proteins).
Causes Dementia.
Picks Disease
Dementia, aphasia, change in personality. only effect the frontal temporal region of brain. Pick bodies: sperical tau prtoein aggregates.
Creutzfeldt-Jakob disease
Rapidly progressive dementia with myoclonus
PrPC->PrPSC which is resistant to proteases. prion disease.
spongiform brain
Vascular dementia
Occurs step-wise due to many TIAs
Seizures
Characterized by synchronized, high frequency neuronal firing.
Partial seizure
Affects 1 area of the brain. Most commonly the temporal lobe. Often preceded by an Aura.
Simple partial seizure
Recordable in one area of the brain and do not have loss or alteration of consciousness, aura common, may become secondarily generalized
Complex partial seizure
Recordable in one area of the brain and result in an alteration of consciousness, aura is common
Absence generalized seizure
Recordable in multiple areas of brain (petit mal), brief little staring spell, no aura, 3 per second spike and wave–very important. No post confusion
Myoclonic generalized seizure
Recordable in multiple areas of brain, sudden jerk, happens normally in sleep but not while awake
Tonic-Clonic generalize seizure
Recordable in multiple areas of brain, Characterized by stiffening and movement.
Tonic generalized seizure
Recordable in multiple areas of brain. Results in sudden stiffining of muscles and fall over like a tree.
Atonic generalized seizure
Recordable in multiple areas of the brain. Characterized by sudden loss of muscle tone and collapse
Glioblastoma
Most common brain tumor. Found in cerebral hemispheres. Tumor of glial cells (astrocytes so stain for GFAP)
Nuclear palisading with vascular necrosis
Meningioma
Second most common brain tumor. Arises from arachnoid cells, Extra-axial (external to brain parenchyma), and may have a dural attachment. typically benign.
Whorls and psammoma bodies (Ca2+)
Schwannoma
Third most common brain tumor. Schwann cell origin often localized to CN VIII (acoustic schwannoma) usually found in cerebellopontine angle. Can affect CN VII & CN V.
Oligodendroglioma
Relatively rare. Slow growing. Most often in frontal lobes. Looks like fried eggs. Chicken-wire capillary networks. Also has calcifications.
Supraoptic nucleus
Makes ADH
Lesion can cause diabetes insipidus
Paraventricular nucleus
Makes oxytocin and ADH
Lesion can cause diabetes insipidus
ADH and Oxytocin
Are both made by the hypothalamus but are stored and released by posterior pituitary
