Rakkudevahelises

Rakkudevahelises is Estonian for “between cells” and describes the space or processes that occur in the region separating adjacent cells, including intercellular signaling, transport and adhesion across cell boundaries.

The intercellular space lies between adjacent cell membranes and contains interstitial fluid and extracellular matrix components such as collagen, laminin and proteoglycans. It enables diffusion of nutrients, gases and signaling molecules and provides mechanical support and tissue organization.

Intercellular communication occurs via gap junctions that connect neighboring cell cytoplasms and permit small molecules to pass, and via paracrine and autocrine signaling released into the space. Synaptic signaling in neurons is a specialized form of intercellular communication. Plants use plasmodesmata to cross cell walls and exchange signals between cells.

Cell junctions regulate the intercellular space. Tight junctions seal gaps; adherens junctions and desmosomes link cells to the cytoskeleton and give tissue strength through cadherins and desmogleins. Integrins connect cells to the extracellular matrix, influencing adhesion and signaling.

In plants, plasmodesmata traverse cell walls to connect cytoplasm of adjacent cells, allowing intercellular transport and signaling across tissues, despite the presence of rigid cell walls.

Clinical relevance: alterations in intercellular space or adhesion affect tissue fluid balance and integrity. Edema expands intercellular spaces; loss of adhesion enables invasion by cancer cells; disruptions of gap junctions can affect coordinated activity in cardiac and neural tissue.