Tight Junction
Tight Junction — a sealing structure between adjacent skin cells that closes the gaps in the space between them, forming a secondary barrier deeper within the epidermis. Located mainly in the granular layer, tight junctions help regulate the movement of water, ions, and small molecules, complementing the outer stratum corneum barrier.
Key points
- Tight junctions are found primarily in the stratum granulosum, beneath the outermost stratum corneum.
- They are built from proteins such as claudins and occludins that seal the space between neighboring cells.
- By controlling paracellular movement, they limit water loss and help keep unwanted substances out.
- Tight junctions work alongside the stratum corneum to create a layered, two-tier skin barrier.
- Impaired tight-junction function has been associated with barrier-compromised conditions such as atopic dermatitis.
Frequently asked
Where are tight junctions located in the skin?
They are concentrated in the granular layer of the epidermis, forming a barrier just below the stratum corneum rather than at the very surface.
Why are tight junctions important for skin health?
They provide a second line of defense that helps control water loss and the passage of molecules, supporting overall barrier integrity when the outer layer is challenged.
Related topics
This is a foundational entry in the SYNC Skin Encyclopedia and is expanded over time. Educational information only — not medical advice.
