What Is the Basilar Membrane?
The basement membrane is an adhesion layer membrane on the basal surface of epithelial cells. Consists of glycoproteins, glycosaminoglycans, and proteins. The base membrane consists of a layer of homogeneous material with a thickness of 50-100 nm, called the substrate (adhered to the cell membrane of the basal surface of epithelial cells) and the deep mesh plate of the substrate. composition. Sometimes the basement membrane of the epithelium is thin, with only the substrate and no stencil. The basement membrane has the function of supporting and connecting the epithelial tissue and the semi-permeable membrane.
- Chinese name
- Basement membrane
- Foreign name
- basal lamina or basement membrane
- Thickness
- 40 ~ 120nm
- Location
- Epithelial and endothelial cells
- The basement membrane is an adhesion layer membrane on the basal surface of epithelial cells. Consists of glycoproteins, glycosaminoglycans, and proteins. The base membrane consists of a layer of homogeneous material with a thickness of 50-100 nm, called the substrate (adhered to the cell membrane of the basal surface of epithelial cells) and the deep mesh plate of the substrate. composition. Sometimes the basement membrane of the epithelium is thin, with only the substrate and no stencil. The basement membrane has the function of supporting and connecting the epithelial tissue and the semi-permeable membrane.
Basement membrane
- The basement membrane is also called the basement membrane. Under the light microscope, it is a thin film located at the interface between epithelial tissue and connective tissue. Earlier studies speculated that this membrane was composed of connective tissue matrix and reticular fibers with varying thicknesses. The stratified squamous epithelium and the trachea pseudostratified ciliated columnar epithelium were thicker, and the other epithelium was relatively thin. The basement membrane of the glomerular capillaries is thick. The capsular capsule of the eye lens is very thick, and its properties also belong to the basement membrane. The basement membrane of the epithelium is not easily identifiable during ordinary staining, and can be clearly stained by PAS reaction or immersion silver method. Recent studies have shown that the base film is not a single-layer film, but consists of two or three layers, but it cannot be distinguished under a light microscope. Under an electron microscope, its main components are a dense mesh and a homogeneous matrix interwoven with 3 to 4 nm diameter filaments, which are 50 to 100 nm thick and are called substrates. The outside of the substrate also has a stencil composed of fine mesh fibers and a matrix, which varies in thickness. The substrate, the reticular fibers and the matrix together constitute the base film as seen by the light microscope. The immersion silver method dyed the reticular fibers in this membrane, and the PAS reaction mainly showed the polysaccharides of the substrate and the reticle. Some epithelial base films are very thin, only the substrate is visible, and no obvious stencil is seen. Therefore, the substrate is now used as a synonym for the base film, and the term base film is increasingly used. Muscle cells, nerve fibers, and some other cells are also coated with a substance similar to the substrate, called the substrate or outer plate. Biochemical analysis showed that the silk of the substrate was type IV collagen, and the matrix contained glycoprotein and mucopolysaccharide. There is evidence that the substrate is a product of epithelial cells, and the reticle is produced by fibroblasts.
- The basement membrane firmly connects the epithelium with connective tissue and becomes a semi-permeable membrane for epithelial cells to exchange materials. This film has other functions, but it is not well understood. It may be an attachment surface for epithelial cells to move. It also plays a role in maintaining the normal shape and structure of the tissue. If the salivary gland's basement membrane is removed during embryogenesis, it cannot grow into a normal glandular structure. The basement membrane of the renal glomerulus is an important barrier to hemofiltration and can prevent the filtration of macromolecular substances. The basement membrane has a considerable effect on tissue growth, differentiation and regeneration. When the muscle or epithelium is damaged, this membrane plays a supporting role, allowing regenerated cells to grow along this membrane. Some malignant tumors do not have a basement membrane, or the basement membrane is ruptured, and tumor cells are prone to metastasis.