<prompt> JG cells juxta glomerular apparatus areMacula densaSmooth muscullar cells of afferent aerioleSmooth muscullar cells of efferent aerioleIslets of epithelial cells  <response>: INDERBIR SINGH;S TEXTBOOK OF HUMAN HISTOLOGY-PAGE NO:313Juxtaglomerular cells the muscle cells in the wall of the afferent aerioles are modified.they are large and roundedepitheliumand have spherical nuclei. their cytoplasm contains granules that can be stained with special methods. these are called juxtaglomerular cells 