Prosancephaly
no brain
anterior neuropore did not close
myeloschesis
no lumbar cord
posterior neuropore didnt close
myelomeningocoele
non functional/ swollen lumbar cord
late closure of posterior neuropore
spina bifida
laminae of the vertebrae dont meet
Structure of Neurons
10% of cells
Axons; central and peripheral processes, dendrites
function of the axons of neurons
peripheral and central processes (central in sensory neurons), tau, transmitter vesicles.
functions of the dendrites of neurons
spines, receptors.
how to increase conduction speed
thickness of the axon, thickness of myelin, increase inter-nodal distance
schwan cells
insulate PERIPHERAL nerves
SUPPORT regeneration of cut axons
oligodendrocytes (40%)
insulate CNS axons
PREVENT regeneration of cut axons
astrocytes
- direct blood flow
- scavenge K+ at synapse
- creates glymphatic space during sleep
where can you find the primary sensory neurons
dorsal root ganglia (spinal ganglia)
lateral motor nuclei of C5-8 and L2-S3
lower motor neurons
IPSIlateral arm and leg
3* syphilis
tabes dorsalis (disease of the spinal cord)
wasting of the fasciulous gracilis
loss of proprioception in the legs
B12 polyneuropathy
demylelination thats starts at the fasciculus gracilis
Multiple Sclerosis
myelin autoimmunity
random loss of spinal tracts
Cuneate and gracile nuclei carry ____ sensory
general somatic
epicritic sensation from the spinal ganglia (dorsal root ganglia) via
Cuneate ARM and gracile LEG tract
the cuneate and gracile nuclei project to
ventroposterolateral thalamic nucleus
the cuneate and gracile nuclei project to the ventroposterolateral thalamic nucleus via
internal arcuate fibers and CONTRAlateral medial leminiscus
the postreior spinocerebellat tract carries information on muscle strech in leg from
from IPSIlateral dorsal thoracic nucleus
the posterior spinocerebellar tract carries information on muscle stretch in the leg from ____
ipsilateral dorsal throacic nucleus
principal contributor to the restiform body
posterior spinocerebellar tract
the posterior spinocerebellar tract synapses on
the cortex of the anterior lobe of cerebellum
The Accessory (lateral) cuneate nucleus RECEIVES muscle stretch information from
the ARM
via superficial fibers in tractus cuneatus
the superfiical fibers in the tractus cuneatues send
muscle stretch information from the arm
cuneocerebellar tract joins
restiform body
cuneocerebellar tract synapses on
cortex of anterior lobe of cerebellum
the anterolateral system
the lateral spinothalamic tract and fellow travelers (whatever that means)
in the anterolateral system, axons of 2 neurons are in
contralateral nucleus proprius of spinal cord
in the anterolateral system, axons of 2 neurons crossed in
anterior white commissure of spinal cord
the anterolateral system carries __ sensation from
Protopathic sensation from opposite limbs to ipsilateral VPL thalamic nucleus
where is the posterior pain pathway (inflammation) located?
Medial edge of fasciculus gracilis
Shwannoma of VIII (acoustic neuroma) causes
facial paresis (VII) and Vertigo (flocculus)
Argyll-Robertson Pupil
NO light reflex, QUICK accomodation (3 syphilis)
Adie’s Pupil
SLOW light reflex, SLOW accomodation (diabetic neuropathy
Oculomotor Nucleus is found
upper midbrain
trochlear nerve is found
lower midbrain
abducens nucleus is found
lower pons
the oculomotor nerve innervates
superior rectus, medial rectus, inferior rectus, inferior oblique
levator palpebrae superioris
the trochlear nerve innervates
superior oblique
crosses (oppoite side)
Abducens nucleus innervates
lateral rectus
the nucleus prepositus (prepositus hypoglossi)
fixes gaze
loss of nucleus prepositus causes
spontaneous nystagmus
the nucleus prepositus is controlled by
contralateral frontal eye field (area 8)
nystagmus
vestibular nuclei input directly to lower motor neurons
slow nystagmus
counters head movement. beat is fast recovery in the direction of movement
head turns right
fast component right, slow component left. nystagmus beats right
automatic ocular tracking
superior colliculus and parietal association cortex control
voluntary ocular tracking
frontal eye field (area 8) and parietal association cortex (area 7 control)
medial longitudinal fasciculus links
eye muscle nuclei and vestibular nuclei
vestibular nuclei
special somatic sensory
where is the vestibular nuclei located
pontomedullary border
the vestibular nuclei has direct reciprocal connection to
nucleus fastigius
what connects the vestibular nuclei to the nucleus fastigius
the juxtarestiform body (vestibulocerebellar tract)
the vestibular nuclei has direct connections to ____ via the medial longitudinal fasiculus
oculomotor, trochlear, abducens nuclei
damage to the MLF causes
prevent nystagmus
visceral motor nuclei are all
preganglionic parasympathetic
the actions of the visceral motor nuclei are opposed by
postganglionic sympathetic fibers from superior cervical ganglion via carotid plexus
accessory oculomotor (edinger-westfall) gets light information from
pretectal nucleus
the pretectal nucleus sends information about
light
the projections from the pretectal nuclues to the accessory oculomotor
crossover in the posterior commissure, making pupillary reflex consensual
pressure in the posterior commissure would cause
abolished consensual light reflex
where does the accesory oculomotor nucleus receive convergence/accomodation information from
oculomotor nucleus
the accessory oculomotor (edinger westfall) project to
ciliary ganglia
short ciliary nerves control
constrictor pupilae and ciliary muscles
dorsal motor nucleus of vagus projects to postganglionis parasympathetic neurons where?
in bronchi and gut to left colic flexure
the bronchi and gut receive postganglionic parasympathetic innervation from
the dorsal motor nucleus of vagus
postganglionis parasympathetic innervation of the bronchi and gut
constriction of bronchi
stimulates secretion and peristalsis in gut
Branchial Motor Nuclei
special visceral motor
motor root of trigeminal innervates
jaw muscles and tensor tympani (1st arch)
facial innervates
- stapedius to dampen loud noise (2nd arch)
- facial muscles (buccinator and orbicularis oculi)
- external genu in facial canal of petrous part of temporal bone
swelling of the petrous part of the temporal bone causes
self limiting bells palsy
nucleus ambiguus projects to
larynx
the nucleus ambiguus projects to larynx via
recurrent laryngeal nerve
nucleus ambiguous sends preganglionic parasympathetics where?
to the heart via the vagus nerve
where does CN X (Vagus) leave
between the olive and posterior spinocerebellar tract
Accessory nerve is found
lowest medulla and C1-6
accessory (XI) innervates
trapezius and sternocleidomastoid
primary sensory neurons are in
glanglia (except mesencephalicnucleus of V)
secondary sensory neurons are in
cranial nerve nuclei
rostral solitary nucleus surrounds the solitary tract where
lower pons
solitary tract brings taste info DOWN from
geniculate ganglion of VII (facial)
genicular ganglion of facial (from solitary tract)
- taste from the antrior 2.3 of tongue
2. chorda tympani
solitary tract brings taste UP from
petrosal (inferior glossopharyngeal) ganglion
caudal solitary nucleus surrounds solitary tract where?
Upper medulla
petrosal ganglion innervated carotid sinus via
sinus nerve of Hering
solitary tract brings blood pressure info from
petrosal ganglion to caudal solitary nucleus
solitary nucleus projects to nucleus ambiguous to
slow heart rate
carotid sinus reflex
solitary nucleus to nucleus ambiguous to slow heart rate
ventrolareral pontomedullary border (retrotrapezoid nucleus) senses
pH (ppCOS2)
ventrolareral pontomedullary border projects information about pH and ppCO2 to the
inspiratory center
the area postrema sense
toxins, projects to vomiting center
sends information about toxins to the vomiting center
the area postrema
trigeminal nuclei
general somatic sensory
mesencephalic nucleus is found
upper pons and midbrain
the mesencephalic nucleus contains primary sensory neurons for
muscle and tendon stretch
the mesencephalic nucleus project to
motor nuclei of cranial nerves
principal sensory nucleus is found
mid pons
the principal sensory nucleus has __ sensation
epicritc
the principal sensory nucleus receives input from
primary neurons in ipsilateral trigeminal ganglion
the principal sensory nucleus projects to both ventroposteromedial thalamic nuclei via
anterior (crossed) and posterior (uncorssed) trigeminothalamic tracts
spinal trigeminal nucleus is found
medulla and C1
spinal trigeminal nucleus carries __sensation
protopathic
spinal trigeminal nucleus protopathic input from
primary neurons in trigeminal ganglion via spinal tract of V (trigeminal)
spinal trigeminal nucleus receives information about ___ from the vagus nerve
pain in the eardrum
the spinal trigeminal nucleus projects to _______ via the anterior trigeminothalamic tract
contralateral VPm thalamic nucleus
blood supply of the olive
vertebral artery and branches
anterior spinal artery supplies
pyramids and medial leminisucs
posterior inferior cerebellar artery supplies
inferior cerebellar peduncle vestibular nuclei and spinal tract of trigeminal (V)
what forms the basilar artery
both vertebral arteries
the basilar artery is the sole blood supply of
the pons
the paramedian branches of the basilar artery supply
basis pontis and medial tegmentum
basilar artery’s circumflex branches supply
middle cerebellar peduncle and lateral tegmentum
superior cerebellar branches of basilar supply
superior cerebellar peduncles
posterior cerebral artery is the terminal branches of
basilar artery
medial paramedian branch of posterior cerebral artery supply
cerebral peduncles
posterior communicating branch of posterior cerebral supplies
midbrain tegmentum
quadrigeminal branch of posterior cerebral artery supplies
superior and inferior colliculi
lateral ventricles are connected to the 3rd ventricle via
foramen of monroe
the 3rd ventricle is connected to the 4th via
cerebral aqueduct
a blockage of the cerebral aqueduct causes
non communicating hydrocephalus
4th ventricle connected to subarachnoid space via
foramina of luschka
subarachnoid space into superior sagittal sinus via
arachnoid granulations
a blockage of the arachnoid granulations causes
communicating hydrocephalus
the cerebrum, diencephalon, and midbrain are aware of and control
the contralateral side of the body
axial muscles are usually ___ controlled
bilaterally
cerebellum usually tones and coordinates
contralateral muscles
the cerebellum tones and coordinates contralateral muscles via
VL thalamus and motor cortex
cerebellum damage causes
hypokinetic syndromes
disequilibrium
flocculonodular lobe
truncal paresis
instability, fall to lesioned side- vermis/fastigial nucleus
wernickes ataxia
thiamine deficiency- anterior lobe
wernickes encephalopathy involved
heart
hypotonia
anterior lobe/glucose emboliform nuclei
dysdiadochokinesis
resolution of movment-poteriorlobe/denate nucleus
blood supply to anterior lobe of cerebellum
superior cerebellar artery
blood supply to the posterior lobe and flocculus of cerebellum
anterior inferior cerebellar artery
papez circuit
hippocampus to mammillary body to anterior thalamus to cingulate gyrus to hippocampus
reward circuit
septal nucleus to medial habenula to interpeduncular to nucleus accumbens (D1)
aversive pathway:
ventral pallidum to
lateral habenula
to
interpeduncular nucleus
fear: freeze, flee or flight
amygdala
stria terminalis
bed nucleus
septal nuclei
loss of amygdala
foolhardiness
pressure on amygdala
hyperaggression
medial forebrain bundle integrates limbic system
IP Hypothamalus septal nuclei nucleus accumbens orbital cortex
bed of nucleus of stria terminalis
gender identity
episodic memory
cortex to hippocampus to mamillary body to anterior thalamus to cortex
anterograde amnesia
inability to learn new facts and events
retrograde amnesia
inability to recall old facts and events
Thalamoperforating branch of posterior cerebral
centromedian
anterior thalamic nucleus
ventral anterior
ventolateral
thalamogeniculate branch of posterior cerebral
ventroposterolateral
ventroposterimedial
lateral geniculate
meidal geniculate
centromedian function of thalamic nuclei
wakefullness
anterior thalamic nucleus function
episodic memory and emotion (papez circuit)
ventral anterior function of thalamic nuclei
mediate basal nuclei initiates movement
ventroposterolateral function of thalamic nuclei
contralateral somesthesia, trunk and limbs
ventroposteromedial function of thalamic nuclei
somethesia, head (pain crossed, epicritc bilateral)
lateral geniculate
vision in contralateral field
medial geniculate
hearing, sound discrimination
supraoptic region
Dorsolateral preoptic nucleus Dorsomedial preoptic nucleus Ventromedeial preoptic nucleus INAH3 Suprachiasmatic nucleus
tuberal region
Supraoptic nucleus
Arcuate nucleus
Ventromedial nucleus
Lateral Nucleus
mammillary region
mamillary nucleus
posterior nucleus
Dorsolateral preoptic nucleus -
sleep
Dorsomedial preoptic nucleus -
temperature
Ventromedeial preoptic nucleus -
GnRH
INAH3
sexual orientation
Suprachiasmatic nucleus
circadian rhythm
Anterior hypothalamic nucleus
parasympathetic
Paraventricular nucleus
oxytocin
Supraoptic nucleus
ADH
Arcuate nucleus
TRH, SRH, CRH, NpY to lateral nucleus, alphaMSH to ventromedial nucleus
Ventromedial nucleus
satiety, serotonin to inhibit lateral nucleus
Lateral nucleus
appetite
Mammillary nucleus
episodic memory, mood, affect
mamillary nucleus is vulnerable to
thiamine deficiency
Posterior nucleus
sympathetic
putamen + globus pallidus =
lenticular nucleus
putamen + caudate =
striatum
striatum + globus pallidus =
corpus striatum
corpus striatum + subthalamic nucleus + substantia nigra
basal nuclei
Medial globus pallidus inhibits
VA
Subthalamic nucleus stimulates
medial globus pallidus, prevents random movement
Substantia nigra - starts movement by
by inhibiting lenticular nucleus
D1
stimulatory dopamine receptor (striatum, preoptic hypothalamus, nucleus accumbens)
inhibitory acetylcholine receptor (D1 neurons in putamen)
D2
inhibitory dopamine receptor (striatum)
stimulatory acetylcholine receptor (D2 neurons in putamen)
D3
inhibitory dopamine receptor in pontine reticular formation
NMDA
fragile stimulatory glutamate receptor (cerebrum, corpus striatum)
GABA
always inhibitory (globus pallidus, thalamus, nucleus ceruleus)
Medial striate
(recurrent branch of A2 of anterior cerebral)
Head of caudate nucleus
facilitates pronunciation
Lenticulostriate branches of M1 of middle cerebral
Putamen & lateral globus pallidus
Anterior choroidal branch of internal carotid
Medial globus pallidus
Medial globus pallidus
inhibits movement
medial striate- recurrent branch of A2 of anterior cerebral
head of caudate nucleus
Huntington’s
progressively worse small jerks (autosomal dominant gene) RARE
Hemiballismus
constant large jerks (stroke)
Tardive dyskinesia
constant facial movements: reaction to chronic dopamine blockade (Haldol etc)
Sydenham’s
temporary sequel of scarlet fever UNCOMMON
Narcolepsy
sudden sleep attacks (idiopathic or reaction to overstimulation of dopamine receptors)
Hyperkinetic - damage to basal nuclei
Huntingtons Hemiballismus tardive syndenhams narcolepsy
hypokinetic damage to basal nuclei
Parkinson’s
Parkinson’s
hard to start movement, progressive bradykinesia, facial immobility, anterograde walking, resting tremor - caffeine confers some protection COMMON
Hyperkinetic - due to defect in pontine D3 receptors
Restless legs
Restless legs
kicking in sleep (autosomal dominant gene) COMMON
Upper motor neuron lesion
spastic paralysis below lesion
Lower motor neuron lesion
flaccid paralysis at lesion
C5-T1: arm
L3-S3: leg
Peripheral nerve lesion
flaccid paralysis of destination muscle - temporary with good suture of nerve
Lesion above pyramidal decussation
spastic paralysis on opposite side
Lesion below pyramidal decussation
paralysis on same side
Anterior corticospinal tracts are redundant
lesions are symptomatic only if bilateral
Loss of Wernicke’s area:
fluent aphasia
Loss of Broca’s area
mute aphsia
Small pyramidal cells
intracerebral projection
large pyramidal cells
project to internuncial neurons in cord
large pyramidal cells are found
areas 2,3,4,67
Betz cells
project to LMN
Betz cells are found
area 4 only
Intermediolateral nucleus
preganglionic sympathetic neurons
Medial motor nucleus
LMN for trunk muscles
Anterior spinal artery
supplies all but posterior funiculus & substantia gelatinosa
Dorsal thoracic nucleus
2o neurons for muscle stretch, origin of posterior spinocerebellar tract
Lateral spinothalamic tract
protopathic from opposite side