intercellular junctions_2

BY: MADIHA SHAMS BDS (1 S T YEAR)

GROUP: A DOW UNIVERSITY OF HEALTH SCIENCES

INTERCELLULAR JUNCTIONS

JUNCTIONS BETWEEN CELLS

When Cells come into contact with each other, various junctional arrangements may form. They are classified as follow:

TIGHT (Occluding) JUNCTIONS

•Tight junctions, or Zonula occludens arethe closely associatedareas of two cells whose membranes join together forminga virtually impermeable barrier to fluid. It is a type ofjunctional complex present only in vertebrates.

• Tight junctions, combine well with membranes of adjacent cells by anInterlocking Systemof occluding ridgesmuch like the teeth ofa zipper.

JUNCTION COMPLEX

Tight Junction + Adhesive Junction

ANCHORING (Adhering) JUNCTIONS

ZONULA ADHERENS

Zone of belt-desmosome or Adherens Junction

MACULA ADHERENS-DESMOSOMES

In Cardiac Muscle In Epithelial Tissue

Hemidesmosomes

(Half-Desmosome) : They connect intermediate Filament to Basal and separate plasma membraneof cell from Basal Lamina.

FOCAL ADHESION

• Adherens junctions calledFOCAL ADHESION can join a cell to the ECM, primarily through fibronectinreceptors.

GAP (Communicating) JUNCTIONS

Cytoplasmic bridgebetween cells for passing chemical &electrical signals. They are frequentlyfound in epithelial Cells.Mostly in heart &nerves, but can be found in liver, pancreas, ovary.