1. Characteristic locations of epithelia within the body. A
Characteristic locations of epithelia within the body. A. Section of the surface of the skin, which consists of layers of epithelial cells that provide covering and protection (arrow indicates the height of epithelium). B. Section of the small intestine (jejunum), lined with a single layer (arrow) of epithelium specialized for absorption and secretion. C. Section of a kidney showing the parenchyma, which contains several types of epithelial-lined tubules (*) involved in urine formation. D. Junctions involved in organizing epithelia. Desmosomes contain adhesive cadherin proteins that make strong connections between adjacent epithelial cells. Hemidesmosomes and focal adhesion complexes contain integrins that link epithelia to the basal lamina. Keratin filaments bind to the cytoplasmic face of desmosomes and hemidesmosomes, whereas focal adhesions are associated with the actin cytoskeleton. Gap junctions directly connect the cytoplasms of neighboring cells, coordinating the physiology of an epithelium. E. Desmosomes link skin epithelial cells together. Slight cell shrinkage causes these attachments to appear as spines between the cells (arrow). F. Section of the epididymis. In most tissues, the basement membrane is too thin to be distinguished with the light microscope; the periodic acid–Schiff (PAS) reaction shown has stained the carbohydrate components of the basement membrane red (arrow). (PAS stain)
Source: EPITHELIUM, The Big Picture: Histology
Citation: Ash R, Morton DA, Scott SA. The Big Picture: Histology; 2017 Available at: Accessed: November 04, 2017
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