et_04. Simple columnar microvillous epithelium
(Jejunum, hematoxylin-eosin)
1. Find the epithelial layer on the surface of intestinal villuses:
- all epithelial cells contact the basal membrane – they make up a layer and have the same columnar shape, borders between the epithelial cells are well-defined;
- the most common type is columnar bordered epithelial cells (the nuclei are oval and are placed in the basal regions of the cells, their surface contains an absorbing (brush) border - a number of microvilli in the apical part of the cell);
- find goblet cells - light-colored cells extended in the middle and filled with mucus, you can see them between columnar epithelial cells; goblet cells have nuclei in the basal region flattened on the outer side;
- loose connective tissue underlies the basal membrane.
2. Draw. Point out:
- 1 - loose connective tissue,
- 2 - basal membrane,
- 3 - bordered epithelial cells (enterocytes),
- 4 - goblet epithelial cells.
3. Define and write significant features of the epithelium and its embryonic origin.