EM 043 Intestinal Glands

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Intestinal Glands

Transmission electron microscopy (TEM) of the epithelium at the base of an intestinal gland (or crypt of Lieberkühn) in the small intestine.

Several types of cells can be tentatively identified:

(orange) - narrow, tall cells adjacent to Paneth cells
- Self-renew and produce progenitor cells
(tan) - progenitor cells that undergo rapid cell division and differentiate as they move up from the crypt to the villi
- Produce enterocytes, goblet cells, Paneth cells, and enteroendocrine cells
Paneth Cells (green; ,) - filled with large, electron-dense secretory granules (purple) clustered near the lumen of the crypt
- Remain at the base of the crypts
- Secrete antimicrobial peptides, such as defensins, and enzymes, such as lysozyme, and phospholipase A2
- Provide crucial signals for maintaining and proliferation of these cells
- Long lifespans compared to other intestinal cells
(red) - scattered cells that release hormones into the bloodstream
- Secrete gastrin, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), or somatostatin
- Important part of the gut-brain axis that regulates digestion, appetite, and metabolism

Subcellular Structures