FOR A PDF DOCUMENT OF THIS INFORMATION, CLICK: http://content.lib.auburn.edu/cdm/singleitem/collection/vetmed1/id/985- These two PS's show the lamina reticularis (or reticular lamina) portion of the basement membrane of smooth muscle in two specific planes of section (PS 19) and beneath the lining epithelium (PS 20). In PS 19 the reticular fibers are illustrated around the smooth muscle cells and PS 20 at the base of the simple columnar epithelium of the intestinal tract. Note: the dark stained areas at the tips of the arrows.
Basal lamina (a division of a basement membrane) is the boundary between epithelium and underlying connective tissue. It is produced by the epithelial cells and has two subdivisions.
1. Lamina lucida - a pale area adjacent to the basal cell membrane of the epithelium, and
2. Lamina densa - outer zone (area) adjacent to the underlying connective tissue.
The main constituents of the basal lamina are:
1. The glycosaminoglycan (heparan sulfate)
2. A fibrous protein (collagen type IV)
3. Structural glycoprotein
a. Fibronectin
b. Laminin
c. Entactin
Lamina reticularis is the second subdivision of a basement membrane that is produced by fibroblasts in connective tissue or perhaps smooth muscle cells when present in smooth muscle.
1. Contains Type III collagen (which stains with silver stains), some Type I collagen fibers, and Type VII collagen (anchoring fibrils).
