QS Study

The cerebrum is the part of the brain involved in the higher levels of thinking and action. It is involved in the control of voluntary and involuntary movement as well as balance. The cerebellum is located behind the top part of the brain stem and is made of two hemispheres.

Histological structure of the cerebellum

The cerebellum consists of –

(A) Outer cortex of grey matter Consists of three layers:

Outer molecular layer – Contains outer stellate and inner basket cells. Contains two main types of neurons: stellate cells and basket cells, which are scattered among dendritic ramifications and numerous thin axons that run parallel to the long axis of the folio.

Purkinje cell layer – Contains Purkinje cells and Golgi cells. The axons of Purkinje cells provide the only efferent pathway to the deep cerebellar nuclei, and thus Purkinje cells constitute the sole output of all motor coordination in the cerebellar cortex.

Granular layer – Consists of numerous small, rounded granule cells with large nuclei. The axons of granule cells rise vertically into the molecular layer, where they bifurcate at a T junction, the branches run parallel to the long axis of the cerebellar folium and synapse with dendrites of the Purkinje cells.

Histological Structure of Cerebellum 1

Fig: Histological Structure of Cerebellum

(B) Inner medulla of white matter:

It is located underneath the cerebellar cortex. It is made up of three groups of fibres –

  1. Intrinsic fibres – Don’t leave the cerebellum, but connect up different regions of the organ.
  2. Afferent fibres – Form the greater part of the white matter & proceed to the cerebellar cortex.
  3. Efferent fibres – Constitute the output of the cerebellum.

(C) Central nuclei of grey matter:

The anterior grey column contains motor neurons. These synapse with interneurons and the axons of cells that have travelled down the pyramidal tract. It is located on the surface of the cerebellum. It is tightly folded, forming the cerebellar cortex.

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