1. Cell junctions:
The epithelial cells are connected to each other laterally as well as to the basement membrane by junctional complexes called cell junctions.
2. The different types of cell junctions are as follows:
a. Gap Junctions (GJs):
These are intercellular connections that allow the passage of ions and small molecules between cells as well as exchange of chemical messages between cells.
b. Adherens Junctions (AJs):
They are involved in various signalling pathways and transcriptional regulations.
c. Desmosomes (Ds):
They provide mechanical strength to epithelial tissue, cardiac muscles and meninges.
d. Hemidesmosomes (HDs):
They allow the cells to strongly adhere to the underlying basement membrane. These junctions help maintain tissue homeostasis by signalling.
e. Tight junctions (TJs):
These junctions maintain cell polarity, prevent lateral diffusion of proteins and ions.
