et_05. Stratified squamous non-keratinized epithelium
(Esophagus, hematoxylin-eosin)
1. Find the epithelial layer lining the esophagus. Study thoroughly the morphology of stratified squamous non-keratinized epithelium:
- On the basal membrane you can see tall columnar cells with axially-orientated oval nuclei – the basal layer;
- the basal layer underlies several layers of epithelial cells having polyangular shape and circular-shaped nuclei – the spinous layer;
- on the surface of the layer there are several coats of fine squamous cells with hyperchromic nuclei stretched on the horizontal axis - the squamous layer.
- loose connective tissue underlies the basal membrane.
- count the total number of epithelial cells in the layer and separately – within
the spinous layer and squamous layer consequently.
2. Draw a segment of the epithelium. See to the number of cells in each layer (it is recommended to proceed from the basal membrane up to the surface of the layer), and point out:
- 1 - loose connective tissue,
- 2 - basal membrane,
- 3 - epithelial cells in the basal layer,
- 4 – epithelial cells in the spinous layer,
- 5 - epithelial cells in the squamous layer.
3. Define and write significant features of the epithelium and its embryonic origin