Contacts between adjoining epithelial cells on thelateralsideFromfreeendtowardsbasalthereare4tvpesofcontactsbetweenadjoiningcellsonlateralsideofthesimplecolumnarepithelium?1.Tight junctions (belttype):somefusions ofcell membranepreventlargemoleculesfrompassingthroughintercellularspace.2.lntermediatejunction(belttype):thecytoplasmicfilamentsareanchoredtothedensematerialoncvtoplasmicfacesofthecellmembranetoform terminalweb,functioningassupport3.Desmosome (plague type):it is a spot-weld type in cell to cellattachment.Somefilamentsconnectthedesmosomeplaguesacrosstheintercellularspaceandintermediateline(fusionofthecellcoatsglycocalyx)
Contacts between adjoining epithelial cells on the lateral side ❖ From free end towards basal there are 4 types of contacts between adjoining cells on lateral side of the simple columnar epithelium: ❖ 1. Tight junctions (belt type): some fusions of cell membrane prevent large molecules from passing through intercellular space. ❖ 2.Intermediate junction (belt type): the cytoplasmic filaments are anchored to the dense material on cytoplasmic faces of the cell membrane to form terminal web, functioning as support. ❖ 3. Desmosome (plague type): it is a spot-weld type in cell to cell attachment. Some filaments connect the desmosome plaques across the intercellular space and intermediate line (fusion of the cell coats, glycocalyx )
4.Gap junction (spottype):a series of microwholespassthroughthenarrow intercellularspace,about3nm.lItis an area of lowelectricalresistancetoionicflow,involvedincelltocell communicationThe combined above tight, intermediateand gap junctions mayconstituteajunctionalcomplex, althoughthetight junction,desmosomeandgap junctionmayexistindependentlyNotice:these junctionsalsoexist in eachkind of primarytissues,notlimitedintheepithelialtissue
❖ 4.Gap junction (spot type ) : a series of microwholes pass through the narrow intercellular space, about 3nm. It is an area of low electrical resistance to ionic flow, involved in cell to cell communication. ❖ The combined above tight, intermediate and gap junctions may constitute a junctional complex, although the tight junction, desmosome and gap junction may exist independently. ❖ Notice: these junctions also exist in each kind of primary tissues, not limited in the epithelial tissue