𝐄𝐏𝐈𝐓𝐇𝐄𝐋𝐈𝐀𝐋 𝐓𝐈𝐒𝐒𝐔𝐄𝐒

Epithelial tissues are present in different parts of the body and perform a variety of functions that are vital in the human body. Specifically, epithelial tissue plays a role in the secretion through producing substances, absorption of essential molecules, protection against pathogens through the skin, and transportation through facilitating the movement of solutes.

A typical feature of epithelial tissue includes:

(1) Cellularity, which they are composed of tightly packed cells.
(2) Display of polarity, with apical, lateral, and basal cell surfaces.
(3) Intercellular junctions which maintain cell-to-cell adhesion.
(4) Basement membrane, which separates epithelial tissue from underlying connective tissue. And, lastly,
(5) Epithelial tissue lacks blood vessels – avascular.

The specialized structures that help adhesion between cells are Integrins. Integrins are transmembrane proteins that link the actin cytoskeleton inside the cell to molecules in the extracellular matrix. They play an important role in relaying signals and controlling cell motility.

References:
National Cancer Institute. Epithelial Tissue. SEEK Training Module. https://training.seer.cancer.gov/anatomy/cells_tissues_membranes/tissues/epithelial.html
Vaukovic, J. (2023). Origin and Types of Epithelial Tissue. Kenhub. https://www.kenhub.com/en/library/anatomy/overview-and-types-of-epithelial-tissue