Anatomy Bones and Muscles · MU Pleven

125. Grey matter of the spinal cord.

Describes the butterfly-shaped grey matter of the spinal cord and its functional division into anterior, intermediate and posterior horns, covering somatic motor, visceral motor and sensory roles. Explains the ten Rexed laminae and the named nuclei within them, such as the marginal nucleus, substantia gelatinosa and the motor nuclei of lamina IX with their segmental levels and muscle targets.

Inside: 3 sections · 5 labelled pictures · 10 flashcards · 2 min

Topic 124 of 236 in the MU Pleven syllabus for Anatomy Bones and Muscles (Medicine, Year 2). The free AceMed note covers it in 3 sections, about 354 words (2 min of reading), with 10 flashcards.

In this note

  1. GRAY COLUMNS OF THE SPINAL CORD.
  2. Division :
  3. Lamina :

GRAY COLUMNS OF THE SPINAL CORD.

  • The gray matter of the spinal cord is a butterfly-shaped structure made up of neuronal cell bodies (inside CNS → nucleus, outside CNS → ganglion), glial cells and neuropile (unmyelinated axons, dendrites & glial cell processes).

Division :

  • The gray matter can be functionaly divided into 3 main regions :
  1. 1. Anterior horn: responsible for somatic motor function. (skeletal muscles)
  2. 2. Intermediate horn: contain lateral horn (T1-L2) responsible for visceral motor function. (heart...)
  3. 3. Posterior horn : responsible for sensory functions
  • Somatic sensation : picking up sensations from the skin, skeletal mus, joints, tendons & ligaments.
  • Visceral Sensation from internal organs.

Lamina :

  • The gray matter of the spinal cord can also be divided into layers (Rexed Lamina)
  • They are 10 laminae in total.
  • I - VI → Posterior horn
  • VII → Intermediate horn
  • VIII + IX → Anterior horn
  • X → Central Zone.

There are specific nuclei that are present in each lamina & have specific functions.

  1. 1. Marginal nucleus : (lamina I) (for pain & temp.)
  • → Receiving pain / temp. sensation. (Fast pain → "A-δ fibers") via the spinothalamic tract
  1. 2. Substantia gelatinosa of Ronald (II)
  • → Receiving pain / temp. sensations (slow pain) → "C-fibers" via spinothalamic tract.
  1. 3. Nucleus proprius (III + IV) :
  • → Pain / temp. → "A-δ + C fibers"
  • → touch / vibration → "A-β fibers". via proprioception.
  1. 4. Lamina (V):
  • → Pain / temp. from the Viscera.
  1. 5. lamin (VI)
  • → limb reflexes
  1. 6. Lamina VII
  • → Clarks column
  • → Interomediomedial nucleus (S2-S4)
  • → Interomediolateral nucleus. (T1-L2)
  • → Sympathetic and parasympathetic preganglion neurons (type of neu cells that transmit signals from the CNS to ganglia of PNS) for the Visceral organs sit in lamina VII.
  1. 7. Lamina VIII :
  • → helps to modulate movement and muscle tone.
  1. 9. lamina X : where axons cross over from one side to another
  1. 8. Lamina IX :
  • Posterior → Supplying flexors
  • Anterior → " Extensors
  • lateral: only in Enlargements; S: Distal limbs
  • Central: S: Proximal limbs
  • Medial: S: Axial musculature "neck + head"
  • Phrenic (C3-C5) → Diaphragm
  • Accessory spinal (C1-C6) → Sternocledio mastoid → Trapezius
  • Onufs nucleus (S2-S4) → sphincter (external)

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