Tight Junctions
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Summary
Tight Junctions, also called zonula occludens or occluding junctions, are cell junctions that function by knitting the membranes of two adjacent cells tightly together, forming a watertight barrier. These junctions are often found in locations exposed to fluids that they must contain - like the linings of the intestines, kidneys and the bladder. On the cellular level, tight junctions are created by coupling the actin Microfilaments of neighboring cells together.
Key Points
- Tight Junctions
- Also called zonula occludens or occluding junctions
- Forms a watertight seal
- Occludin proteins press plasma membranes of adjacent cells tightly against each other
- Bound by cytoskeletal Microfilaments, made of actin
- Found in the Intestines, Kidney/Bladder, and the blood brain barrier (BBB)
- Impermeable barriers contain fluids, prevent leakage, and control absorption
- Tight junctions fully encircle the apical area of every cell in the epithelial sheet to form a watertight layer