Neuroanatomy/Physiology Flashcards
Nissl substance
RER
Astrocytes functions lesser known
K+ metabolism, glycogen fuel reserve buffer, reactive gliosis in response to neural injury. GFAP is astrocyte marker. Dervied from neuroectoderm.
Microglia lesser known facts
mesodermal origin. Not readily discernible in Nissl stains. irregular nuclei, small, little cytoplasm. HIV-infected microglia fuse to form multinucleated giant cells in the CNS.
What effect does myelin have
Increases space constant and inc. conduction velocity
Oligodendroglia lesser known facts
Neuroectoderm, “fried egg” on H&E stain. Injured in MS, progressive multifocal leukoencephalopathy (PML), and leukodystrophies.
Progressive multifocal leukoencephalopathy
JC virus in HIV patients. Breaks down white matter, attacking oligodendroglia.
Schwann cells lesser known facts (LNFs)
Neural crest origin. Destroyed in Guillain-Barre syndrome.
Acoustic neuroma
Type of schwannoma, internal acoustic meatus (CN VIII): bilateral is neurofibromatosis type 2
What layer of peripheral nerve attacked in Guillain-Barre
endoneurium
What layer is fixed with microsurgery in peripheral nerve?
perineurium (permeability barrier)
What is the epineurium
Deep connective tissue that surrounds entire nerve (fascicles and blood vessels)
What is endoneurium
It surrounds the axons, but is not the myelin. It holds the axon in the equivalent of CSF.
C fibers
slow, unmyelinated for pain and temp
Adelta fibers
fast, myelinated for pain and temp
Which sensory corpuscle adapts slowly
merkel discs
Locus ceruleus NT and location
NE and pons
Ventral tegmentum and SNc NT and location
DA and midbrain
Raphe nucleus NT and location
5-HT and pons, medulla, midbrain
Basal nucleus of Meynert NT
ACh
Nucleus accumbens NT
GABA
Openings in Blood-Brain Barrier
Area postrema: vomiting after chemo OVLT: osmotic sensing Neurohypophysis release of ADH/oxytocin
What is the OVLT?
Organum vasculosum of lamina terminalis. Senses osmotic pressure in blood. HYPOTHALAMUS
Hypothalamus functions
TAN HATS: Thirst and water balance. Adenohypophysis. Neurohypophysis. Hunger. Autonomic regulation. Thermoregulation. Sexual urges.
Where is ADH made?
Supraoptic nucleus
Where is Oxytocin made?
Paraventricular nucleus
Lateral hypothalamus
Makes you hungry (grow laterally), damage makes anorexic. Inhibited by leptin.
Ventromedial hypothalamus
Makes you satiety. Stimulated by leptin. Damage makes you grow laterally and ventrally. Can be damaged by craniopharyngioma.
Anterior hypothalamus
Anterior cooling. parasympathetic
Posteriro hypothalamus
Heating, sympathetic. If you destroy posterior, you become poikilotherm (cold-blooded)
Suprachiasmatic nucleus function
Sleep
Suprachiasmatic nucleus pathway
NE release to pineal gland to melatonin
What NTs controlled at night by circadian rhythm
ACTH, prolactin, melatonin, NE
What causes the EOMs of REM sleep
PPRF (paramedian pontine reticular formation/conjugate gaze center)
What affects REM sleep and delta wave sleep
Alcohol, benzos, and barbs decrease both REM and delta wave sleep
NE affects REM how
Dec. REM sleep
Treating sleep enuresis
DDAVP, better than imipramine
Treating night terrors and sleepwalking
Benzos
Highest frequency EEG waves
Beta, when eyes open, alpha is slowly frequency with eyes closed
Where are theta waves
N1 (5%)
Sleep spindles and K complexes
N2 (45%)
Delta waves when
N3 (25%) deepest sleep
Where does sleepwalking, night terrors and bedwetting occur
N3
REM wave pattern
Beta
Sleep wave mnemonic
At night, BATS Drink Blood (beta, alpha, theta, sleep spindles/k complexes, delta, beta)
Thalamus receives what senses
Everything except smell
Thalamus VPL
Receives spinothalamic and dorsal columns/medial lemniscus: pain/temp, position/pressure/touch/vibration. Relays to primary somatosensory cortex.
Thalamus VPM
From trigeminal and Gustatory pathway for face sensation and taste to primary somatosensory cortex.
VPM mnemonic
Makeup goes on the face. (VPM)
Thalamus LGN
CN II for vision, goes to Calcarine sulcus
LGN mnemonic
Lateral = Light
Thalamus LGM
From superior olive and inferior colliculus of tectum for hearing. Goes to auditory cortex of temporal lobe.
MGN mnemonic
Medial = Music
Thalamsu VL
From basal ganglia and cerebellum for motor info, relays to the motor cortex
Structures of limbic system
Hippocampus, amygdala, fornix, mammillary bodies, and cingulate gyrus
Functions of limbic system
Emotion, long term memory, olfaction, behavior modulation, ANS function
Limbic system mnemonic
Famous 5 F’s: Feeding, fleeing, fighting, feeling, and sex
Cerebellum inputs
Contralateral cortex via middle cerebellar penducle Ipsilateral proprioceptive info via inferior cerebellar peduncle from the spinal cord (input nerves=climbing and mossy fibers)
What are the cerebellar peduncles
They are the tracts that connect the cerebellum to the brainstem.
Excitatory pathway of Basal Ganglia
This is the direct pathway. Inputs from contralateral cerebral cortex land on putamen (as well as D1 input from SNc) which inhibits the Globus Pallidus Internus which disinhibits the thalamus which increases movement.
Inhibitory pathway of Basal Ganglia
Indirect pathway. Putamen inactivates the GPe which disinhibits the STN which activates the GPi inhibition of the thalamus to decrease movement. D2 input stops the putamen efferents which decrease movement.
What makes up the striatum
Putamen (motor) + caudate (cognitive)
What is the lentiform nucleus
Putamen + globus pallidus
What does D2 receptors do
Inhibits the inhibitory pathway
What does D1 receptors do
Activates the excitatory pathway
What is the SNr
Along with the GPi inhibits the thalamus. Deactivated by the direct pathway and activated by the indirect pathway.
What disease has Lewy bodies and found where?
Parkinsons, intranuclear eosinophilic alpha-synuclein inclusions with loss of DA neurons in SNc
Signs of Parkinson’s
TRAPS: Tremor, cogwheel Rigidity, Akinesia (bradykinesia), Postural instability, Shuffling gait
Sxs of huntingtons
Choreiform movements, aggression, depression, dementia
Huntington path
Decreased GABA and ACh in brain. Neuron death from NMDA-R binding and glutamate toxicity.
Huntington genetics
CAG repeats (anticipation). Aut. dom. on Chromosome 4. Between ages 20-50.
Hemiballismus description and location
Contralateral subthalamuc nucleus (e.g. lacunar stroke), 1 arm +/- ipsilateral leg.
Athetosis seen where
Fingers, in huntingtons