neuro - basics (NTK!) Flashcards
gracile and cuneate tract separated by ?
post intermediate sulcus
gracile tract starts from ?
sacral and coccygeal input
cuneate tract starts from?
around T6-T5
in the ‘dorsal column tracts’
sacral region is located more _
cervical region is located more_
vs
in the ‘lateral tracts’ (asc. spinothalamic and desc. corticospinal)
cervical region is located more _
sacral region located more _
dorsal column
sacral = medial
cervical = lateral
lateral tracts
cervical = medial
sacral = lateral
BODY - dorsal column medial lemniscus
information for…
pathway..
1st origin.. travel.. travel .. * synapes and terminate..
2nd origin.. decussate.. travel.. synapse and terminate..
3rd
origin..
terminate
Dorsal column medial lemniscus (asending)
- upper limb = fasciculus cuneatus (T6-C2)
- lower limb = fasciculus gracilis (sacral and coccygeal)
- touch
- press
- proprioception
1st
origin = DRG
travel = asc. or desc. - 1 or 2 levels in the lissaur’s tract
travel up *not decuss yet =
dorsal column fasiculus (gracilus or cuteatus)
synapse and terminate =
ipsi. nucleus gracilis or cuneatus - in (closed medulla)
2nd (a "projection neuron") origin = closed medulla decussate = closed medulla travels up = medial lemniscus synapses and terminate = thalamus (VPL)
3rd
origin = thalamus (VPL)
terminate = cortex (on respected homunculus area of somatosensory cortext/ postcentral gyrus)
BODY - anterolateral / spinothalamic
information for..
pathway..
1st
origin =
travels =*
synapse and terminate =
2nd (a "projection neuron") origin = decussates = travels up = synapses and terminate =
3rd origin = terminate = lower limb- upper limb
anterolateral / spinothalamic (ascending)
- pain and temp (lateral)
- crude touch (anterior)
1st
origin = DRG (at level of spinal cord)
travel*= 1 or 2 lvls - lissaur’s tract
synapse and terminate = ipsi. dorsal horn
(rexed lamina lvl 2 = substantia gelatinosa)
2nd (a “projection neuron”)
origin = dorsal horn (at level)
decussates = anterior white commissure (at level)
travels up = spinal lemniscus contralaterlly
(aka sp.thal tract past medulla)
synapses and terminate = thalamus (VPL)
3rd origin = thalamus (VPL) terminate = somatosensory cortex / postcentral gyrus (on respected homunculus area) lower limb - superior cortex upper limb - lateral cortex
descending pathways exit through..
- through vental ROOT
subparts of the anterolateral / spinothalamic system ? * 4
- spino/thalamic
- spino/reticular
- spino/mesencephalic or spino/tectal
- spino/hypothalamic
- spinothalamic (direct, main one, pain/temp/crude touch)
- spinoreticular ( indirect, c. alertness and arousal in response to stim, activation of the noradrenergic system - termiate brainstem norepinephrin NE neurons and reticular formation)
- spinomesencephalic / spinotectal (indirect orients the head and eyes towards stimulus)
- spinohypothalamic (pain evoked endocrine response)
name anterolateral system 1st 2nd 3rd order neurons
1st = sensory neuron 2nd = interneuron 3rd = relay neuron
BODY - corticospinal tract
*** upper motor neurons / lower motor neurons
information for..
pathway..
1st upper motor neuron origin= travel = travel = and become travel = decuss = 85% fibres - travel in= synapse= terminate =
2nd - lower motor neuron
orig =
term=
cont. travel ipsi= 15% continue as decussate = synapse = terminate = 1. 2. 3.
cortico/spinal tract (descending)
- lateral cortico = appendicular mus
- anterior cortico = axial mus
85%
1st upper motor neuron
origin= primary motor cortex (precentral gyrus)
travel = internal capsule
travel = cerebral peduncle (become in medulla)
travel = medulla - ‘pyramidal tracts’
decuss = 85% fibres - medulla pyramids
(junction of medulla and sp. cord)
travel in= lateral corticospinal tract
synapse= contra. ventral horn, syn w lower motor neuron/ terminate = at level sp. cord
2nd - lower motor neuron
orig = ventral horn
term= (appendicular) mus
15%
cont. travel ipsi= 15% continue as anterior corticospinal tract
decussate = anterior white commisure (at level sp. cord)
synapse = contra. ventral horn (at spinal level)
terminate = lower motor neurons (axial mus)
*trunk mus
*posture mus
*subconcious controlled mus
HEAD - spinal trigeminal tracts / trigemino-thalamic system
Sensory
- spinal trigeminal pathway
- chief sensory trigeminal pathway
- mesencephalic
information for .. pathway... 1st -touch, pressure, prop (chief sensory) origin = enter = synapse/term = decuss = mid pons vs - pain and temp (spinal trigeminal) origin = enter = travel= synapse = *for chief some stay ipsilateral for propriocetion - mesencephalic (reflex proprioception)
2nd orig= decuss = ascd = synapse and terminate =
3rd
orig =
term =
spinaltrigeminal tract
Sensory
- pain and temp (HEAD) = spinal trigeminal nucleus
- touch, press, proprio (HEAD) = chief sensory nucleus
- reflex proprioception (HEAD) = mesecephalic
1st -touch, pressure, prop (chief sensory) origin = trigeminal ganglion enter = mid pons (level) synapse/term = - ipsi. mid pons > chief sensory nucleus decuss = mid pons vs - pain and temp (spinal trigeminal) origin = trigeminal ganlion enter = mid pons travel= desc to caudal medulla synapse = ipsi. caudal medulla > spinal trigeminal nucleus
- for chief some stay ipsilateral for propriocetion
- mesencephalic (reflex proprioception)
2nd origin= caudal med (spinal tri nucl) or pons (chief sens nu) decuss = caudal medulla or pons ascd = trigeminal lemniscus synapse and terminate = thalamus (VPM)
3rd
orig = thalamus VPM
term = ipislateral cortical areas (SI and SII)
mechanoreceptors *4
- meissner (corpuscles) = motion detection/grip control
- merkel (cells) = shape/texture
- ruffini (corpuscles) = tangential force, hand shape, motion detection
- pacinian (corpuscles) = distant events thu vibration
Sensory for the HEAD comes mainly from… nerves
but also from…nerves
mainly - cn 5 (trigeminal)
but also
- cn 7 facial
- cn 9 glossopharangeal
- cn 10 vagus
HEAD - corticobulbar pathway
(not tract more just fibres - bulbar means brainstem)
Motor
pathway..
corticobulbar
- motor (HEAD)
1st
origin = primary motor cortex (precentral gyrus)
travel =
-internal capsule
- cerebral peduncles (wh become) corticobulbar fibres
- leave the tract
synapse = cranial nerve nuclei (equiv to ventral horn neurons)
HEAD - corticobulbar pathway
(not tract more just fibres - bulbar means brainstem)
Motor
pathway..
corticobulbar
- Motor pathway (spinal 5)
1st
origin = primary motor cortex (precentral gyrus)
travel =
-internal capsule
- cerebral peduncles (wh become) corticobulbar fibres
- leave the tract
synapse = cranial nerve nuclei (equiv to ventral horn neurons)
