Difference between revisions of "SpinalCordOld"

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<pre style="color: green">Spinal Cord</pre>
 
<pre style="color: green">Spinal Cord</pre>
 
[[Home]] -> [[BiologicalLifeResearch]] -> [[SpinalCord]]
 
[[Home]] -> [[BiologicalLifeResearch]] -> [[SpinalCord]]
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== SPINAL CORD SENSORY AND MOTOR ROOTS NEURONS ==
 
== SPINAL CORD SENSORY AND MOTOR ROOTS NEURONS ==
  
−
*Fibers by thickness*:
+
'''Fibers by thickness''':
  
 
* '''A-alpha motor/sensory (Ia, Ib)''': 12-22 mcm, 70-120 m/sec, low theshold, 2ms after stimulus (motoneurons, touch, position and velocity, Meissner's corpuscles)
 
* '''A-alpha motor/sensory (Ia, Ib)''': 12-22 mcm, 70-120 m/sec, low theshold, 2ms after stimulus (motoneurons, touch, position and velocity, Meissner's corpuscles)
Line 62: Line 61:
 
** postganglionic parasympathetic C fibers (from ganglia in/on wall of organ, visceral activity and repose, short, local)
 
** postganglionic parasympathetic C fibers (from ganglia in/on wall of organ, visceral activity and repose, short, local)
  
−
*Sensory neurons*:
+
'''Sensory neurons''':
  
 
http://www.intechopen.com/source/html/43833/media/image2.jpeg
 
http://www.intechopen.com/source/html/43833/media/image2.jpeg
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** '''Muscle spindles''': skeletal muscle, stretch by muscle length (fast), A-alpha-Ia/A-beta
 
** '''Muscle spindles''': skeletal muscle, stretch by muscle length (fast), A-alpha-Ia/A-beta
  
−
*Motoneurons*: '''Motoneurons''':
+
'''Motoneurons''':
  
 
http://classconnection.s3.amazonaws.com/997/flashcards/1355997/gif/reflexarcs1336087730891.gif
 
http://classconnection.s3.amazonaws.com/997/flashcards/1355997/gif/reflexarcs1336087730891.gif
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* '''renshaw cell''': axon collateral of alpha-motoneuron -> renshaw cell -> alpha-motoneuron (negative feedback)
 
* '''renshaw cell''': axon collateral of alpha-motoneuron -> renshaw cell -> alpha-motoneuron (negative feedback)
  
−
*Motor interneurons*:
+
'''Motor interneurons''':
  
 
http://www.ib.cnea.gov.ar/~redneu/2013/BOOKS/Principles%20of%20Neural%20Science%20-%20Kandel/gateway.ut.ovid.com/fulltextservice/ct%7B06b9ee1beed594190674f1983457a7dd32af6a0d5a4c9892~43/da6c36ff5.gif.png
 
http://www.ib.cnea.gov.ar/~redneu/2013/BOOKS/Principles%20of%20Neural%20Science%20-%20Kandel/gateway.ut.ovid.com/fulltextservice/ct%7B06b9ee1beed594190674f1983457a7dd32af6a0d5a4c9892~43/da6c36ff5.gif.png
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== SPINAL CORD NUCLEI ==
 
== SPINAL CORD NUCLEI ==
  
−
http://ahuman.googlecode.com/svn/images/wiki/research/biomodel/spinal-cord-nuclei.jpg
+
http://usvn.ahuman.org/svn/ahwiki/images/wiki/research/biomodel/spinal-cord-nuclei.jpg
  
−
*outer:* '''outer:'''
+
'''outer:'''
 
* [[BrainRegionBMA_SC_LH_LCV|Lateral Cervical Nucleus]] (LCN) (lateral horn, low-threshold fast-conducting, tactile/pressure relay); sensory, tract of Lissauer/spinocervical tract; A-alpha-Ib/A-beta/A-delta sensory data
 
* [[BrainRegionBMA_SC_LH_LCV|Lateral Cervical Nucleus]] (LCN) (lateral horn, low-threshold fast-conducting, tactile/pressure relay); sensory, tract of Lissauer/spinocervical tract; A-alpha-Ib/A-beta/A-delta sensory data
 
* [[BrainRegionBMA_SC_LH_LSN|Lateral Spinal Nucleus]] (LSN) (lateral horn, relay in unmyelinated pathways between the periphery and brain, intersegmental integrator); sensory, spinohypothalamic tract/spinosolitary tract; A-delta/C sensory data
 
* [[BrainRegionBMA_SC_LH_LSN|Lateral Spinal Nucleus]] (LSN) (lateral horn, relay in unmyelinated pathways between the periphery and brain, intersegmental integrator); sensory, spinohypothalamic tract/spinosolitary tract; A-delta/C sensory data
  
−
*sensory:* '''sensory:'''
+
'''sensory:'''
  
 
http://www.bioon.com/bioline/neurosci/course/body4.gif
 
http://www.bioon.com/bioline/neurosci/course/body4.gif
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* [[BrainRegionAVA_SC_IZ_IMM|Intermediomedial Nucleus]] (IMM) - LVII (visceral sensory); sensory, ventral spinocerebellar tract; A-alpha-Ia sensory data
 
* [[BrainRegionAVA_SC_IZ_IMM|Intermediomedial Nucleus]] (IMM) - LVII (visceral sensory); sensory, ventral spinocerebellar tract; A-alpha-Ia sensory data
  
−
*motor:* '''motor:'''
+
'''motor:'''
 
* '''Medial Motor Nuclei''' (axial muscles motor neurons)
 
* '''Medial Motor Nuclei''' (axial muscles motor neurons)
 
** [[BrainRegionBMA_SC_VH_PM|Posteromedial Nucleus]] (PMN), Dorsomedial Nucleus - LIX (axial trunk flexors, T1-L2); flexor motor, lateral vestibulospinal tract/medullary reticulospinal tract; A-alpha-Ia/A-beta/A-gamma motor data
 
** [[BrainRegionBMA_SC_VH_PM|Posteromedial Nucleus]] (PMN), Dorsomedial Nucleus - LIX (axial trunk flexors, T1-L2); flexor motor, lateral vestibulospinal tract/medullary reticulospinal tract; A-alpha-Ia/A-beta/A-gamma motor data
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* [[BrainRegionAVA_SC_CC_DCN|Dorsal Commissural Nucleus]] (DCN) - LX (integrate direct/indirect excitatory and inhibitory fast inputs, modulate by slow excitatory responses); interneurons from Intermediolateral Nucleus
 
* [[BrainRegionAVA_SC_CC_DCN|Dorsal Commissural Nucleus]] (DCN) - LX (integrate direct/indirect excitatory and inhibitory fast inputs, modulate by slow excitatory responses); interneurons from Intermediolateral Nucleus
  
−
*autonomic:* '''autonomic:'''
+
'''autonomic:'''
 
* '''Intermediolateral Cell Column''', Intermediate Zone:
 
* '''Intermediolateral Cell Column''', Intermediate Zone:
 
** [[BrainRegionAVA_SC_IZ_IML|Intermediolateral Nucleus]] (IML) - LVII (autonomic, visceral structures); sympathetic, visceral motor; dorsolateral tract; interneurons from Marginal Nucleus; B motor data
 
** [[BrainRegionAVA_SC_IZ_IML|Intermediolateral Nucleus]] (IML) - LVII (autonomic, visceral structures); sympathetic, visceral motor; dorsolateral tract; interneurons from Marginal Nucleus; B motor data
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(generated)
 
(generated)
  
−
<img src="http://thebrain.mcgill.ca/flash/a/a_03/a_03_cl/a_03_cl_dou/a_03_cl_dou_1d.jpg">
+
<img src="http://ahuman.org/svn/ahwiki/images/ext/d7fd94d000e86c1c218aa45a3f9a31c3.jpg" alt=(null)
  
−
|| '''Level/Lamina''' || '''LO''' || '''LI''' || '''LII''' || '''LIII''' || '''LIV''' || '''LV''' || '''LVI''' || '''LVII''' || '''LVIII''' || '''LIX''' || '''LX''' ||
+
{| class=wikitable width=80%
−
|| C1 || LCN || MN || SG || NPR || NPR || || || CCN || VMN || SAN || ||
+
| '''Level/Lamina''' || '''LO''' || '''LI''' || '''LII''' || '''LIII''' || '''LIV''' || '''LV''' || '''LVI''' || '''LVII''' || '''LVIII''' || '''LIX''' || '''LX'''
−
|| C2 || LCN || MN || SG || NPR || NPR || || || CCN || VMN || SAN || ||
+
|-
−
|| C3 || LCN || MN || SG || NPR || NPR || || || CCN || VMN || SAN,PHN || ||
+
| C1 || LCN || MN || SG || NPR || NPR || || || CCN || VMN || SAN ||
−
|| C4 || LCN || MN || SG || NPR || NPR || || || CCN || VMN || SAN,PHN,PLN,VLN || ||
+
|-
−
|| C5 || LCN || MN || SG || NPR || NPR || || || CBN || VMN || SAN,PHN,PLN,VLN || ||
+
| C2 || LCN || MN || SG || NPR || NPR || || || CCN || VMN || SAN ||
−
|| C6 || LCN || MN || SG || NPR || NPR || || || CBN || VMN || SAN,PLN,VLN || ||
+
|-
−
|| C7 || LCN || MN || SG || NPR || NPR || || || CBN || VMN || PLN,VLN || ||
+
| C3 || LCN || MN || SG || NPR || NPR || || || CCN || VMN || SAN,PHN ||
−
|| C8 || LCN || MN || SG || NPR || NPR || CLN || CLN || CBN,RPL || VMN || PLN,VLN || ||
+
|-
−
|| T1 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM,RPL,CSC || VMN || PMN || ||
+
| C4 || LCN || MN || SG || NPR || NPR || || || CCN || VMN || SAN,PHN,PLN,VLN ||
−
|| T2 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM,CSC || VMN || PMN || ||
+
|-
−
|| T3 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || ||
+
| C5 || LCN || MN || SG || NPR || NPR || || || CBN || VMN || SAN,PHN,PLN,VLN ||
−
|| T4 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || ||
+
|-
−
|| T5 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || ||
+
| C6 || LCN || MN || SG || NPR || NPR || || || CBN || VMN || SAN,PLN,VLN ||
−
|| T6 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || ||
+
|-
−
|| T7 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || ||
+
| C7 || LCN || MN || SG || NPR || NPR || || || CBN || VMN || PLN,VLN ||
−
|| T8 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || ||
+
|-
−
|| T9 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || ||
+
| C8 || LCN || MN || SG || NPR || NPR || CLN || CLN || CBN,RPL || VMN || PLN,VLN ||
−
|| T10 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || ||
+
|-
−
|| T11 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || ||
+
| T1 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM,RPL,CSC || VMN || PMN ||
−
|| T12 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || ||
+
|-
−
|| L1 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || DCN ||
+
| T2 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM,CSC || VMN || PMN ||
−
|| L2 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN,PLN,VLN || DCN ||
+
|-
−
|| L3 || || MN || SG || NPR || NPR || CLN || CLN || || VMN || PLN,VLN || ||
+
| T3 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN ||
−
|| L4 || || MN || SG || NPR || NPR || || || || VMN || PLN,VLN || ||
+
|-
−
|| L5 || || MN || SG || NPR || NPR || || || || VMN || PLN,VLN || ||
+
| T4 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN ||
−
|| S1 || || MN || SG || NPR || NPR || || || RPL,SPS || VMN || PLN,VLN,ONN || DCN ||
+
|-
−
|| S2 || || MN || SG || NPR || NPR || || || RPL,SPS || VMN || ONN || DCN ||
+
| T5 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN ||
−
|| S3 || || MN || SG || NPR || NPR || || || RPL,SPS || VMN || ONN || DCN ||
+
|-
−
|| S4 || || MN || SG || NPR || NPR || || || || VMN || || DCN ||
+
| T6 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN ||
−
|| S5 || || MN || SG || NPR || NPR || || || || VMN || || ||
+
|-
−
|| CX || || MN || SG || NPR || NPR || || || || VMN || || ||
+
| T7 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN ||
 +
|-
 +
| T8 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN ||
 +
|-
 +
| T9 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN ||
 +
|-
 +
| T10 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN ||
 +
|-
 +
| T11 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN ||
 +
|-
 +
| T12 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN ||
 +
|-
 +
| L1 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN || DCN
 +
|-
 +
| L2 || LSN || MN || SG || NPR || NPR || CLN || CLN || IML,IMM || VMN || PMN,PLN,VLN || DCN
 +
|-
 +
| L3 || || MN || SG || NPR || NPR || CLN || CLN || || VMN || PLN,VLN ||
 +
|-
 +
| L4 || || MN || SG || NPR || NPR || || || || VMN || PLN,VLN ||
 +
|-
 +
| L5 || || MN || SG || NPR || NPR || || || || VMN || PLN,VLN ||
 +
|-
 +
| S1 || || MN || SG || NPR || NPR || || || RPL,SPS || VMN || PLN,VLN,ONN || DCN
 +
|-
 +
| S2 || || MN || SG || NPR || NPR || || || RPL,SPS || VMN || ONN || DCN
 +
|-
 +
| S3 || || MN || SG || NPR || NPR || || || RPL,SPS || VMN || ONN || DCN
 +
|-
 +
| S4 || || MN || SG || NPR || NPR || || || || VMN || || DCN
 +
|-
 +
| S5 || || MN || SG || NPR || NPR || || || || VMN || ||
 +
|-
 +
| CX || || MN || SG || NPR || NPR || || || || VMN || ||
 +
|}
  
 
== SUBCORTICAL SENSORY SYSTEMS ==
 
== SUBCORTICAL SENSORY SYSTEMS ==
Line 207: Line 239:
 
http://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Spinal_cord_tracts_-_English.svg/800px-Spinal_cord_tracts_-_English.svg.png
 
http://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Spinal_cord_tracts_-_English.svg/800px-Spinal_cord_tracts_-_English.svg.png
  
−
*ASCENDING*: '''ASCENDING''':
+
'''ASCENDING''':
  
 
* '''dorsal column''', posterior column, medial lemniscus (well-localized discriminative fine touch and proprioception, alpha/beta mechanoreceptors, conscious):
 
* '''dorsal column''', posterior column, medial lemniscus (well-localized discriminative fine touch and proprioception, alpha/beta mechanoreceptors, conscious):
Line 261: Line 293:
 
*** '''rostral spinocerebellar tract''' (RSCT): C8-L3,proprioceptive/fine touch/vibration (body, legs) to [[BrainRegionAVA_PN_SG_DRG|Dorsal Root Ganglion]] (N1) to [[BrainRegionBMA_SC_IZ_CBS|Centrobasalis Nucleus]] (N2) to [[BrainRegionMBA_HP_CR|Cerebellum]] (bilaterally)
 
*** '''rostral spinocerebellar tract''' (RSCT): C8-L3,proprioceptive/fine touch/vibration (body, legs) to [[BrainRegionAVA_PN_SG_DRG|Dorsal Root Ganglion]] (N1) to [[BrainRegionBMA_SC_IZ_CBS|Centrobasalis Nucleus]] (N2) to [[BrainRegionMBA_HP_CR|Cerebellum]] (bilaterally)
  
−
*DESCENDING*: '''DESCENDING''':
+
'''DESCENDING''':
  
 
http://o.quizlet.com/OvyHXzkWIfq4piBE7gtbUw.png
 
http://o.quizlet.com/OvyHXzkWIfq4piBE7gtbUw.png
Line 310: Line 342:
 
**** [[BrainRegionHMA_MM_CJ|Cajal Nucleus]] to [[BrainRegionVBA_MM_OCN|Oculomotor Nucleus]] to muscles of eye
 
**** [[BrainRegionHMA_MM_CJ|Cajal Nucleus]] to [[BrainRegionVBA_MM_OCN|Oculomotor Nucleus]] to muscles of eye
  
−
*INTRASPINAL*: '''INTRASPINAL''':
+
'''INTRASPINAL''':
  
 
* A-alpha receptors to [[BrainRegionAVA_PN_SG_DRG|Dorsal Root Ganglion]] (N1) to  
 
* A-alpha receptors to [[BrainRegionAVA_PN_SG_DRG|Dorsal Root Ganglion]] (N1) to  

Latest revision as of 19:10, 28 November 2018

Spinal Cord

Home -> BiologicalLifeResearch -> SpinalCord

This page is intended to discover component structure of spinal cord of biological human, sitting in between mind and peripheral organs.

SPINAL CORD STRUCTURE

BASIC INFORMATIOIN

image002.jpg

  • regions - cervical (C1-C8), thoracic (T1-T12), lumbar (L1-L5), sacral (S1-S5), coccygeal (CX = CX1-CX3)
  • width - 1 cm (thoracic/sacral) /2 cm (cervical-lumbar)
  • height - 45 cm (men)/43 cm (women)

SPINAL CORD SENSORY AND MOTOR ROOTS NEURONS

Fibers by thickness:

  • A-alpha motor/sensory (Ia, Ib): 12-22 mcm, 70-120 m/sec, low theshold, 2ms after stimulus (motoneurons, touch, position and velocity, Meissner's corpuscles)
    • A-alpha-Ia motor/sensory:
      • muscle spindle primary sensory endings (skin, two-point discrimination, extrafusal muscles, Meissner's corpuscles)
      • alpha motoneurons (extrafusal muscle fibers, skeletal movements, brainstem/spinal cord)
        • FF-type alpha motoneurons - biggest motoneurons, type IIB extrafusal muscle fibers (generate large force, poor efficiency, affected by static beta motoneurons)
        • FR alpha motoneurons - type IIA extrafusal muscle fibers (affected by static beta motoneurons)
        • S-type alpha motoneurons - type I muscle fibers (little force, metabolically efficient, affected by dynamic beta motoneurons)
    • A-alpha-Ib sensory:
      • sensory Golgi tendon organs
      • sensory Ruffini endings in skin
  • A-beta motor/sensory (II): 8-13 mcm, 40-70 m/sec, higher theshold, 4ms after stimulus (fine touch, kinesthesia, muscle spindle secondary endings)
    • Merkel disks (weak position and strong velocity - irregular discharge, type I, hairy/hairless skin)
    • Ruffini's corpuscles (strong position and weak velocity receptors - regular discharge, type II, hairy/hairless skin)
    • Hairy skin velocity receptors (large hair follicles, slow and rapid movement of hairs and deflection of the skin)
    • Pacinian corpuscles (transient receptors, connective tissue, vibration, intrafusal muscles, tonic proprioceptive endings, flower-spray type)
    • beta motoneurons (skeleto-fusimotor, intrafusal fibers and collaterals to extrafusal muscle fibers, muscle spindles, increase dynamic sensitivity of ending)
      • beta dynamic motoneurons - type I extrafusal muscle fibers and the intrafusal bag1 fiber (slow contracting motor units)
      • beta static motoneurons - type IIA or IIB extrafusal fibers and the intrafusal bag2 fiber (fast contracting motor units)
  • A-gamma motor: 4-8 mcm, 15-40 m/sec, 6ms after stimulus
    • intrafusal muscle fibers (skeletal muscle tone, contract muscle spindles from both ends, fusimotor gamma neurons, affect Ia/II)
      • gamma static motoneurons - intrafusal bag2 fiber and the nuclear chain fibers
      • gamma dynamic motoneurons - intrafusal bag1 fiber
  • A-delta sensory (III): 1-4 mcm, 5-15 m/sec, 20ms after stimulus
    • noxious receptors (first/fast, sharp, well-localized pain)
    • cold receptors (temperature, high-threshold mechano/heat, phasic)
    • pressure (rapidly adapting mechanosensitive, directional selectivity, crude touch)
  • B motor: 1-3 mcm, 3-14 m/sec, preganglionic autonomic, myelinated, ACh (sympathetic only in T1-L3, IML)
    • preganglionic paravertebral sympathetic (short to paravertebral sympathetic ganglia, close to vertebral, fibers ascend/descend to reach all spinal cord levels)
    • preganglionic prevertebral sympathetic (long to prevertebral sympathetic ganglia, celiac, superior/inferior mesenteric ganglia)
    • preganglionic parasympathetic spinal (spinal cord long fibers to parasympathetic ganglia, splantic nerves, abdominal organs)
    • preganglionic parasympathetic cranial (cranial nerves III, VII, IX and X long fibers to parasympathetic ganglia, eye iris, lacrimal/submandibular/subingual glands, thorax, abdomen, GI tract)
  • C motor/sensory (IV): 0.1-1 mcm, 0.2-2 m/sec, 60ms after stimulus (pain, touch, pressure, temperature, postganglionic autonomic)
    • C fiber nociceptors (responsible for the second, burning pain)
    • C fiber warming specific receptors (responsible for warmth)
    • ultra-slow histamine-selective C fibers (responsible for itch)
    • tactile C fibers (sensual touch, includes CT fibres, also known as C low-threshold mechanoreceptors (CLTM), which are unmyelinated afferents found in human hairy skin, and have a low mechanical threshold < 5 milliNewtons. They have moderate adaptation and may exhibit fatigue on repetitive stimulation and "afterdischarges" for several seconds after a stimulus)
    • C mechano- and metabo- receptors in muscles or joints (responsible for muscle exercise, burn and cramp)
    • postganglionic sympathetic C fibers (muscles and skin, pre/post - temporal summation and spatial summation, one-to-many, wide-spread, long and unmyelinated, NE)
    • postganglionic parasympathetic C fibers (from ganglia in/on wall of organ, visceral activity and repose, short, local)

Sensory neurons:

image2.jpeg

  • Classification by receptor:
    • proprioceptors: LI,LV, also LII (fast pain/temperature senses), A-delta fibers
    • nociceptors: LII,LI (slow pain/temperature senses, unmyelinated), C fibers
    • mechanoreceptors: LIII,LIV (touch/position/kinesthetic/vibration senses), A-alpha-Ia/A-beta fibers

nrn1073-f1.jpg

  • Proprioception
    • receptors origin: muscle spindle (intrafusal fibers), Golgi tendon organ, A-alpha-Ib/A-beta fibers
    • intrafusal fiber types:
      • nuclear chain fibers - report static length of muscle (aligned in a single row), A-alpha-Ia/A-beta/A-gamma fibers
      • static nuclear bag fibers - report static length of muscle (bundle in fiber middle), A-alpha-Ia/A-beta/A-gamma fibers
      • dynamic nuclear bag fibers - report rate of change of muscle length (bundle in fiber middle), A-alpha-Ia/A-gamma fibers
    • roman number fiber classification:
      • Ia - primary afferents, annulospiral endings, length and velocity, A-alpha-Ia fibers
      • Ib - Golgi tendon organ, report load being applied to muscle, A-alpha-Ib fibers
      • II - secondary afferents, flower spray endings, length only, A-beta fibers
  • Sensory endings
    • mc_ch14_fig01.jpg
    • Hair follicle receptors: touch (slowly adapting, low threshold), A-beta fibers
    • Merkel disk receptors: vibration 5-15 Hz (high resolution tactile discrimination, static touch/pressure, mechanoceptors in hairless skin and mucosa, pressure and texture, slowly adapting, sustained response, low threshold), A-beta fibers
    • Meissner's corpuscles: vibration 20-50 Hz (tactile, dynamic touch/pressure, texture, rapidly adapting, superficial papillary receptor, low threshold, especially sensitive to light touch - like fingers and lips), A-alpha-Ia fibers
    • Pacinian corpuscles: vibration 60-400 Hz (deep receptors, subcutaneous tissue, viscera, rapidly adaptng, low threshold), A-beta fibers
    • Ruffini's corpuscles: stretching of skin (deep receptors, slowly adapting, low threshold), A-alpha-Ib/A-beta fibers
    • Free nerve endings: pain, temperature, crude touch, A-delta/C fibers
    • Golgi tendon organs: muscle tension (slowly adapting, low threshold), A-alpha-Ib fibers
    • Muscle spindles: skeletal muscle, stretch by muscle length (fast), A-alpha-Ia/A-beta

Motoneurons:

reflexarcs1336087730891.gif

  • alpha-motoneuron: extrafusal muscle fibres (voluntary movement), A-alpha-1a fibers
  • beta-motoneuron: intrafusal/extrafusal muscle fibres (voluntary movement), A-beta fibers
  • gamma-motoneuron: intrafusal muscle fibers (muscle tonus, additional contracts to maintain sensitivity in stretched state), A-gamma fibers
  • preganglionic autonomic: B fibers
  • postganglionic autonomic: C fibers
  • renshaw cell: axon collateral of alpha-motoneuron -> renshaw cell -> alpha-motoneuron (negative feedback)

Motor interneurons:

da6c36ff5.gif.png

  • interneurons of indirect supraspinal connections: primary pathway for alpha-motoneurons
  • renshaw interneurons: interneurons of direct monosynaptic connections with alpha-motoneurons, some fibers of CST/LVST/RST, negative feedback on the same alpha-neurons; stop firing to be ready for next supraspinal signal
  • integrated rhythmic movements of upper and lower extremities like walking and running
    • intersegmental interneurons: reciprocal inhibition (excite agonist muscles/ inhibit antagonist muscles), feedback inhibition (selectively inhibit LMN to proper pattern in agonist muscle group)
    • commissural interneurons: to contralateral neurons (crossed extensor reflexes, alternate rhythms of both upper and lower extremities during running and walking)

SPINAL CORD NUCLEI

spinal-cord-nuclei.jpg

outer:

  • Lateral Cervical Nucleus (LCN) (lateral horn, low-threshold fast-conducting, tactile/pressure relay); sensory, tract of Lissauer/spinocervical tract; A-alpha-Ib/A-beta/A-delta sensory data
  • Lateral Spinal Nucleus (LSN) (lateral horn, relay in unmyelinated pathways between the periphery and brain, intersegmental integrator); sensory, spinohypothalamic tract/spinosolitary tract; A-delta/C sensory data

sensory:

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  • Marginal Nucleus (MN), Apex of Posterior Horn, Nucleus Posteromarginalis - LI (A-delta/C, somatic sensory, non-modulatable pain and temperature sensations, joint nociception); sensory, tract of Lissauer/spinomesencephalic tract; modulatory, dorsolateral tract (from RVM); interneurons from SG; interneurons to NPR,IML; A-delta/C sensory data
  • Substantia Gelatinosa (SG), Rolando's Substance - LII (C, somatic sensory, short - pain, temperature, long - mechanoreceptors; long inhibits short); sensory, tract of Lissauer; modulatory, dorsolateral fasciculus (from VTA); interneurons to MN, CLN; C sensory data
  • Nucleus Proprius (NPR), Main Sensory Nucleus, Proper Sensory Nucleus - LIII,LIV (A-beta, visceral sensory, crude and pressure, 2-point discrimination, vibration); sensory: lateral spinothalamic tract/spinocervical tract/spinotectal tract/spinoolivary tract; A-alpha-Ib/A-beta/A-delta sensory data
  • Clarke's Nucleus (CLN), Nucleus Dorsalis, Posterior Thoracic Nucleus, Clarke's Column - LV, LVI (A-alpha/A-delta, visceral sensory, secondary visceral afferents, unconscious proprioception): sensory, tract of Lissauer/anterior spinothalamic tract/spinoreticular tract/dorsal spinocerebellar tract; interneurons from SG, NPR; A-alpha-Ia/A-alpha-Ib/A-delta sensory data
  • Central Nucleus (unconscious proprioception)
    • Central Cervical Nucleus (CCN) - LVII (spinocerebellar sensory, relays neck proprioception to cerebellum, locomotion); sensory, spinoolivary tract/spinovestibular tract; A-alpha-Ia/A-alpha-Ib sensory data
    • Centrobasalis Nucleus (CBN) - LVII (spinocerebellar sensory, relays forelimb proprioception to cerebellum); sensory, rostral spinocerebellar tract; A-alpha-Ia sensory data
  • Intermediomedial Nucleus (IMM) - LVII (visceral sensory); sensory, ventral spinocerebellar tract; A-alpha-Ia sensory data

motor:

  • Medial Motor Nuclei (axial muscles motor neurons)
    • Posteromedial Nucleus (PMN), Dorsomedial Nucleus - LIX (axial trunk flexors, T1-L2); flexor motor, lateral vestibulospinal tract/medullary reticulospinal tract; A-alpha-Ia/A-beta/A-gamma motor data
    • Ventromedial Nucleus (VMN), Anteromedial Nucleus - LVIII (axial trunk extensors, inhibit flexors, all segments); extensor motor, ventral corticospinal tract; A-alpha-Ia/A-beta/A-gamma motor data
  • Lateral Motor Nuclei (distal muscles motor neurons)
    • Posterolateral Nucleus (PLN), Dorsolateral Nucleus - LIX (distal flexors, C4-C8/L2-S1, hand/leg, distal muscles of forearm, hand, leg, foot); flexor/extensor motor, lateral corticospinal tract/rubrospinal tract/lateral vestibulospinal tract; A-alpha-Ia/A-gamma motor data
    • Ventrolateral Nucleus (VLN), Anterolateral Nucleus - LIX (distal extensors, C4-C8/L2-S1, shoulder/hip, distal muscles of shoulder girdle, arm, hip, thigh); extensor motor, pontine reticulospinal tract; A-alpha-Ia/A-gamma motor data
    • Spinal Accessory Nucleus (SAN) - LIX (neck, control neck to rotate head); flexor motor, tectospinal tract/medial vestibulospinal tract; A-alpha-Ia/A-beta/A-gamma motor data
    • Phrenic Nucleus (PHN) - LIX (diaphragm, conscious and autonomic control of breathing); visceral motor, ventral corticospinal tract; autonomic motor, solitariospinal tract; A-alpha-Ia/A-beta/A-gamma motor data
    • Retroposterolateral Nucleus (RPL), Retrodorsolateral Nucleus - LIX (fingers, C8-T1/S1-S3, distal large motor neurons to small arm and leg finger muscles); flexor motor, lateral corticospinal tract/rubrospinal tract; A-alpha-Ia/A-gamma motor data
  • Onuf's Nucleus (ONN), Gert's Nucleus, Lumbosacral Nucleus - LIX (dorsomedial: urination, dorsolateral: defecation, external sphincters; orgasmic muscular contractions); flexor motor, dorsolateral tract; interneurons from Sacral Parasympathetic Nucleus; A-alpha-Ia/A-gamma motor data
  • Dorsal Commissural Nucleus (DCN) - LX (integrate direct/indirect excitatory and inhibitory fast inputs, modulate by slow excitatory responses); interneurons from Intermediolateral Nucleus

autonomic:

  • Intermediolateral Cell Column, Intermediate Zone:
    • Intermediolateral Nucleus (IML) - LVII (autonomic, visceral structures); sympathetic, visceral motor; dorsolateral tract; interneurons from Marginal Nucleus; B motor data
    • Ciliospinal Center (CSC) - LVII (autonomic, visceral structures); sympathetic motor, tectospinal tract/hypothalamospinal tract; B motor data
    • Sacral Parasympathetic Nucleus (SPS) - LVII (S1-S3, psym. to large intestine; pelvic nerve); sympathetic motor, dorsolateral tract; interneurons to Onuf's Nucleus; B motor data

SPINAL CORD LAMINAE AND LEVELS

(generated)

(null) Cuneate Nucleus -> VPL - upper body

SENSORY NUCLEI FROM SPINAL CORD TO VPL/VPM

SENSORY NUCLEI FROM SPINAL CORD TO CR

INTERSPINAL SENSORY TO MOTOR

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