NEURO OUTLINEZ

NEUROHISTOLOGY: GREY AND WHITE MATTER

  • Grey matter: Contains cell bodies, dendrites, and unmyelinated fibres.

  • White matter: Composed mostly of myelinated fibres, giving it a whitish appearance.

  • Arrangement:

    • In spinal cord/brainstem: White matter is external, grey matter is internal.

    • In cerebrum/cerebellum: Grey matter forms outer cortex with underlying white matter and isolated grey matter masses (nuclei).

STRUCTURE OF THE CEREBELLUM

  • Located in the posterior cranial fossa with a superficial grey matter layer (cerebellar cortex).

  • Divisions:

    • Vermis (midline) and two lateral hemispheres.

    • Lobular structure due to fissures; primary fissure and posterolateral fissure divide lobes.

  • Folia: Narrow bands on cerebellar surface created by fissures.

HISTOLOGY OF THE CEREBELLAR CORTEX

  • Composed of three layers:

    1. Molecular layer (superficial).

    2. Purkinje cell layer (middle).

    3. Granular layer (deep).

  • Neurons:

    • Purkinje, granule, stellate, basket, Golgi, and brush cells.

GREY AND WHITE MATTER OF CEREBELLUM

  • Grey matter: Cerebellar cortex and nuclei (dentate, emboliform, globose, fastigial).

  • White matter: Central core with cerebellar peduncles, forming the roof of the fourth ventricle.

CEREBRAL CORTEX STRUCTURE

  • Surface features: Includes sulci (grooves) and gyri (ridges), covered by grey matter (cerebral cortex).

  • Deep structures include thalamus, hypothalamus, and basal nuclei (caudate nucleus, lentiform nucleus).

  • Internal capsule: White matter pathway for ascending and descending tracts.

CELL TYPES IN CEREBRAL CORTEX

  • Pyramidal cells: Major cortical neurons with triangular shape.

  • Stellate cells: Smaller, multipolar neurons.

  • Other types: Fusiform, basket, horizontal, neuragliaform, and cells of Martinoti.

LAYERS OF CEREBRAL CORTEX

  • Six layers from superficial to deep:

    1. Plexiform/molecular layer

    2. External granular layer

    3. Pyramidal layer

    4. Internal granular layer

    5. Ganglionic layer

    6. Multiform layer

  • Variability in neuron types across layers, including giant pyramidal cells in the ganglionic layer.