Question

Basement membrane is made up of
(a) Epidermal cells only
(b) Endodermal cells only
(c) Both (a) and (b)
(d) No cells at all, but is a product of epithelial cells

Answer 1

Hint: The basement membrane is like a matrix that is made up of molecules like glycoproteins, laminin, and collagen secreted by the epithelial cells. It also separates the underlying fibrous tissues from the urothelium.

Complete Step by Step Answer:
As you may know, the basement membrane is the fibrous tissue that is used to form a layer and separate the endothelium, epithelium, and the mesothelium layers from the connective tissue that are lying beneath the layers. A network of collagen makes up the basement membrane. The basement membrane is an extracellular formation that covers many of the animal tissue. Inside the basement membrane, the extracellular matrix hence formed is made up of laminin and collagen networks and is linked to each other with extracellular proteins that include perlecan and nidogen. Hence the formation of the basement membrane occurs from the product of the epithelial cells.

Additional Information:
- The basement membrane is actually a very thin sheet made up of protein that separates the endothelium, epithelium, and the mesothelium for the underlying tissues.

- These membranes are also present around some other cells too, like the Schwann cells, muscle cells, and also in the kidney around the glomerulus.
- The basement membrane present around the glomerulus is responsible for ultrafiltration.
- The basement membrane also controls the entry and exit of components from or to the epithelial cells and the nearby blood vessels.
- Cellular adhesion is employed to bind the basement membrane to the surrounding cells. The extracellular matrix present consists of a network of collagen fibers that consist of mucopolysaccharides and of other components like laminin both of which are proteins and are responsible for the cellular adhesion of the basement membrane.
So, the correct answer is, “No cells at all, but is a product of epithelial cells”.

Note:
- The mucopolysaccharides, which are present are also known as glycosaminoglycans, you must know the alternate names.
- You must also note that the basement membrane is also known as basal lamina, these alternate names can also be used in different questions too and may cause confusion.