Week 3

Nervous Tissue Pre-Lab 2

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Large neurons in the cerebellum

Unfortunately, I do not have a good photomicrograph of the cerebellum. However, this folded appearance shown diagrammatically here is easy to recognise in a slide.

The section in your box is not blue-and-pink - it is brownish. The section is stained by a special method that enhances neurons.

The cerebellum has a large number of folds - so thin that they are called folia (leaves). Four such folia are shown here, with the bar (X) indicating the width of one. The outer layer (cortex, shown at A) is packed with neurons, their nuclei showing up as blue dots. (There are two layers of different density in the cortex - a point which we shall overlook.) The almost uniform pink material (B) is the white matter. In your section it will show a network of nerve fibres.

At the junction there is a prominent row of large neuron bodies, shown here as large blue dots (C). Observe one of these under the high magnification.

The large, flask-shaped neuron body is unmistakable. Depending on the plane of the section, the orientation of individual cells may vary. You will have to look for one that looks like the diagram here! A perfect section will show a dendrite and hopefully its few branches towards the surface. In reality the cell has on its cortical (surface) side a huge tree of dendrites.

A single axon leaves the opposite end of the cell. Again, you will have to examine several cells until you find an ideal one.

Observe the usual features of a neuron - the large euchromatic nucleus and the prominent nucleolus.

Beware! This is an idealised drawing. Search the section for appearances closest to this.

 

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