neurons need
second to second supply of O2 and glucose–very limited anaerobic capacity
Sodium cell potential
+65 mv
Parkinsonism symptomology
athetosis (slow, writhing, convoluted, involluntary movements), chorea, pill rolling, festinating gate
muscle reflex has
complimentary IPSP on opposing muscle (i.e. bicep vs tricep)
Basal Ganglia composed of
Striatum, globus pallidus, substantia nigra, subthalamic nuclei
striatum composed of / pathology
caudate nucleus , putaman (chorea), fundus strati
primary brain tumors caused from
glia due to ability to divide vs. neurons
globus pallidus pathology
athetosis
substantia nigra pathology
Parkinson’s
important for hippocampal function
thymine–Wernicke’s encephalopathy (unable to make new memories)
all sensory input except sight goes through
thalamus
hypothalamus involved in
feelings of hunger/thirst, pain, pleasure, major limbic center (rage, tranquility, pleasure, fear) temp control,
Hypothalamus controls
pituitary
Midbrain controls
eye movement, auditory, visual systems–think of how ancient the function is
medulla/ mylencephalon controls
autonomic center, coordinates swallowing, coughing
*. Cerebellar damage
errors in RATE, RANGE, FORCE, and DIRECTION
damage to cerebellum
lack of coordination (ataxia), intention tremors
normal ECF K+ levels
4 meq/l
tremor
rhythmic movement of extremity
Dangerous ECF K+ levels indicative of widespread cell lysis
7-8 meq/l
intention tremor indicative of
cerebellar lesion vs. resting tremor
cells lining ventricles forming CSF
ependymal cells –> produce 500 ml/day
1 of the 4 neuroglia of CNS
CSF found in
ventricles (lateral, 3rd, 4th), cerebral canal, & central canal/ subarachnoid space of SC
CSF sampled btwn
3rd and 4th lumbar vert
Things that are _____ and _____ have trouble getting past BBB
large and charged
children have _____ BBB
incomplete–thus brain infection higher probability–low threshold for infant lumbar puncture
BBB is highly permeable to
H2O, CO2, O2, lipids, non-polar substances
yellow/ green from bruise is
billiruben–can’t cross adult BBB
billiruben in infant brain due to V BBB
Kernicterus, Phenylketonuria (post-natal light therapy used to break down billiruben)
Major commissure of neocortex
corpus callosum
CT dark =
fluid
biconvex hematoma
epidural
crescent moon shaped hematoma
subdural
spinal nerves
31 pairs
impending uncal herniation sign
pupil dilation– pressure puts traction against CN III cutting of parasympathetic innervation thus leaving only sympathetic pupillary tone
motor nerve leaving SC to periphery
lower motor neuron
motor neuron from motor cortex descending SC
upper motor neuron
dorsal horn/ root
sensory/ afferent
carry cold, pressure, and acute pain
A delta fibers – myelinated
transmit steady, dull, constant pain
C fibers – unmyelinated
apex of dorsal horn–for sensory modulation
substantia gelatinosa–act as gates (frequency and transmission of signals)
lower motor neuron cell bodies in
ventral/ anterior horn of SC
Sensory modulation happens at _____ and _______
- level of spinal cord–SG and 2. centrally–in thalamus
Sensory neurons named
ex. first order, second order, third order, etc.
sense organ to SC: first order sensory neuron
spinothalamic nerve: second order sensory neuron
thalamocortical nerve: third order sensory neuron
pain sensation
free nerve ending– C fiber– unmyalenated
perception of pressure to skin
mechanoreceptors
1. pacinian corpuscles-- 2. baroreceptors
pain and temperature (spinothelamic tract) neurons decussate at
the level of the SC that they enter
vibration neurons decussate at (lemniscal tract)
level of medulla – clinically pertinent
upper motor neurons decussate at
pyramids of medulla–for destinations bellow the bulbar (medulla)
partial transection of spinal cord
Brown-Sequard syndrome–pain and temp lost from opposite side and vibration from same side as lesion
craniobulbar
cranial nerves (bulbar=medulla)
motor fibers aka
Alpha fibers (myelenated)
stretch reflex
self contained in SC- (watch videos)
antagonist muscle inhibited
Golgi tendon organ (video)
located in muscle tendon (not meant to stretch)–self contained in SC
- signal sent to SC afferent
- interneurons transmit
- efferent signals sent to corresponding muscle inhibiting further contration (makes muscle flaccid)
- efferent signal sent to antagonist muscle
tends to dampen muscle spindle stretch reflex
upper motor neuron–thus when upper motor neuron lesion DTR’s will be more extreme
hyporreflexive upon reflex hammer test
possible lower motor neuron lesion
hyperreflexive upon reflex hammer test
possible upper motor neuron lesion
when looking at reflexes
compare side to side &
top to bottom
system containing all sub-components of motor system
pyramidal system
principal component of pyramidal system
corticospinal tract
- pyramidal tract pathology (UMN) -know-
weakness, spasticity, hyperactive DTR’s , Babinski sign
great toe extension when sole of foot is stimulated
babinski sign vs flexion normally
inability to perform volitional movements rapidly and with ease.
akinesisa (extrapyramidal system dysfunction), mask-like affect
basal ganglia part of / disfunction?
extrapyramidal system– disfunction–> movement disorder
- extra pyramidal disorder symptoms
akinesisa, mask, ridgidity (lead-pipe, cog-wheel), resting-tremor (clears with intentional movement), pill rolling, athetosis, chorea
sinuous snake-like involuntary movements
athetosis
NONREPETETIVE, jerky, involuntary movements
chorea
famous for extrapyramidal side effects
antipsychotics (neuroleptics)
With spasticity– neuronal death–as from infantile or stroke anoxia is random–is _______, and ______ motor neurons will win out
random, and intact
substantia gelatinosum gated modulation in dorsal horn
put ice on smashed finger– 50% of cold and 50% of pain carried = sensory modulation