Gap junctions are present in

(Smooth muscles) (13-K.S) (92-559-771-Gyton 11th) (16,17,78,85-GN) (39-40-Ganong 23rd)GAP-JUNCTIONS is also called nexus. It is present in heart, basal part of epithelial cells of intestinal mucosa* Gap Junctions - small protein tubular structures, that allow free-free movements of ions from the interior of one cell to the interior of the next. Only a few gap junctions have been found in the CNS. However it is by way of gap junctions and other similar junctions that action potentials are transmitted from one smooth muscle fibre to the next in visceral smooth muscle and from one cardiac muscle cell to the next cardiac muscle (559- Gyton 11th)* Regulation of the diameter of channels in Gap junctions-by the intracellular calcium-ions, also by pH, voltage, hormones or neurotransmitters.