Spinal Cord Flashcards
Gracile Fasciculus
-main touch pathway
-fine touch, vibrations, conscious proprioception
-lower body to brain stem
Grey Matter
-unmyelinated neurons
-motor and sensory
-control movement
-Inside
White Matter
-myelinated neurons
-tracts up and down SC
-Outside
Cuneate Fasciculus
-only in cervical
-vibration and conscious perception and fine touch sensations from upper body
Gracile Nucleus
-dorsal column nuclei in medulla
-fine touch sensation and proprioception of lower body
Cuneate Nucleus
-info from upper body
-nucleus of dorsal column in medulla
Inferior Olivary Nucleus
-coordinate signals from SC to cerebellum to regulate coordination
Middle Cerebellar Peduncle
-connects cerebellum to pons
-largest afferent system in cerebellum
Periaqueductal Grey Matter
-modulation and propagation of pain
Spinal Cord I Zone
-dorsal horn
-marginal zone
-noxious stimuli
Spinal Cord II Zone
-Dorsal horn
-Substantia gelatinosa
Spinal Cord III Zone
-dorsal horn
-Nucleus proprius
-Proprioception
Spinal Cord IV Zone
-dorsal horn
-Nucleus proprius
Spinal Cord V Zone
-Dorsal horn
Spinal Cord VI Zone
-dorsal horn
Spinal Cord VII Zone
-intermediate zone
-Clark’s nucleus
Spinal Cord VIII Zone
-ventral horn
-commissural nucleus
Spinal Cord IX Zone
-ventral horn
-motor nuclei
Spinal Cord X Zone
-grey matter
-Grisea centralis
Spinal Levels Traveling Caudally
-L2-S5
Medial Dorsal Rootlets
-Ia and AB for fine touch and proprioception (DCML)
Lateral Dorsal Rootlets
-AGamma and c fibers for pain and temp (spinothalamic)
Clark’s Nucleus
- T1-L3
-proprioceptive info to cerebellum
Substantia Gelatinosa
-glial and small nerve cells
-spinothalamic
Lateral Horn
-T1-L2
-cell bodies of pregangilonic SNS neurons
Preganglionic PNS Cell Bodies
-S2-S4
Epidural Space
-L3-L4
Order of Spinal Arteries
-Anterior Spinal Artery
-medullary a
-Segmental A.
Mmt of SC
-stretches 10% with flexion
-none for Cauda
Jendrassik’s Maneuver
-changes descending input to alter motor function
Central Pattern Generators
-Rhythmic activity patters generated by central circuits without external cues
-locomotion, swimming, breathing, swallowing, urinating
Stepping Pattern Generators
-type of CPG for walking without cortical output
-flexor-extensor activation using proprioceptive information
-has to be activated
Withdrawal Reflex
-remove noxious input by activating remaining LE to prevent falling
-crossed extension reflex
Reciprocal Inhibition
-inhibits activated of antagonist while turning on agonist
-allows unopposed muscle activity
-allow cocontraction
Recurrent Inhibition
-inhibit agonist and synergist muscles to turn on antagonist
-Renshaw cells activated by reccurent collateral branch of alpha motor neuron
SC Control of Bladder and Bowel
-afferent info needed
-T11-L2 and S2-S4
Frontal Cortex: tells pons to empty OR corticospinal tract to contract PF muscles
Pons: Sends signals to sacral cord center to contract bladder
Sacral Cord: signals parasympathetic neurons to contract bladder and relax sphincters
SC Control of Sexual Function
Psychogenic processes: L1-L2
Reflexogenic Processes: S2-S4
Pudenal: L1-L2 and S2:S4 for orgasm
Injuries
-Above T12: loss of erection and genital sensation
-L2-S2 intact circuits: normal function, no sensation
-S2-S4 circuit lesion: nothing
Vertical Tract Impairments
-ipsi/contra deficits below lesion
Anterior Cord Syndrome
-A. Spinal Artery issue
-Paralysis, analgesia, loss of discriminative sensation, loss of temp below lesion
-Keep proprioception and light touch (DCML)
Central Cord Syndrome
-trauma induced
Small Lesion: pain and nociception impaired at level of lesion
Large Lesion: pain and nociception impaired at level of lesion AND UE motor issues
Brown-Sequard (Hemicord) Syndrome
Ipsilateral segment:
-paralysis and analgesia of everything
Ipsilateral Below:
-Paralysis and loss of proprioception and light touch
Contralateral Below:
-nociceptive and temp impaired
Cauda Equina Syndrome
-sensation impaired, pain, LE paralysis, bowel/bladder
-no hyperreflexia
Tethered Cord Syndrome
- stretch injury, scar tissue
-LE, bowel/bladder, spine issues
Ant. Cauda equina: LMN
Excessive stretch: UMN
Spinal Shock
-24h-3wks
-all reflexes, function and autonomic regulation lost
-end with return of anal reflexes
Post-Traumatic SC Injury
-hyperexcitability and hyperreflexia
-more sensation
-poor thermoregulation
-orthostatic hypotension
-dysreflexia
SC Bowel/Bladder Dysfunction
S2-S4: flaccid a-reflexive bladder
Above S2-S4: hyperreflexive bladder
-reflex emptying or spasms that cause urine to backflow into kidneys
