BASEMENT-MEMBRANE

What is basement membrane?

Basement membrane is a thin extracellular layer that is made up of two layers

  1. Basal lamina
  2. Reticular lamina (lamina means a thin layer)

Basement membrane structure

basement-membrane-structure

Location of basement membrane

The basement membrane is found between epithelial cells and connective tissue cells.

1. The Basal lamina of basement membrane

  • Lies closer to and secreted by epithelial cells.
  • Contains proteins like laminin, collagen, glycoproteins and proteoglycans.
  • These protein molecules adhere to integrins (proteins) in hemidesmosomes to attach epithelial cells to the basement membrane.

2. The Reticular lamina of basement membrane

  • Lies closer to underlying connective tissue cells.
  • Contains collagen protein fibroblasts that is produced by connective tissue cells.

What are the functions of basement membrane?

  1. Anchoring the epithelium to its loose connective tissues.
  2. Supporting the epithelial tissue cells.
  3. Participate in filtration of blood in the kidneys by restricting passage of larger molecules between epithelium and connective tissues.

Diseases associated with basement membrane

Under diseased condition, increase in production of collagen and laminin causes thickening of basement membranes. 

If it remains untreated for prolonged cases of diabetes mellitus, the basement membranes of capillaries get thickened mainly in eyes and kidneys. 

This is the reason how chronic diabetic patients suffer from blindness and kidney failure.