Fig. 5

Morphological characteristics of poison glands of type PER, typical from the margins of the parotoids and other macroglands. (a) Note that in the parotoid all described glandular types (COM, PAR and PER) are present. (b) High magnification of the parotoid margin showing PER poison glands at different stages of development. Note that one of these glands shows an epithelial plug (PL). A mucous gland is seen on the duct side (arrow). (c) Margin of the parotoid where a PER gland is observed on the side of a PAR gland. Note again a mucous gland (arrow) next to the glandular duct. (d) High magnification of a region equivalent to that marked by the rectangle in the previous image. Note the difference between the granules of PER and PAR glands. PER glands have subunits, while PAR glands are light and homogeneous and fuse to each other. (e) Differently from PAR glands, PER glands do not present polarization of cytoplasm organelles. gr, granules; my, myoepithelial layer; n, nucleus; syn, syncytium. (f) Poison granules (gr) have internal subunits. (g) Cytoplasm organelles disperse amongst poison granules (gr). gol, Golgi apparatus, rer, rough endoplasmic reticulum. Species: Rhinella marina (a-d), Rhinella icterica (e-g). Histological sections (a-d). Staining: haematoxylin-eosin (a-c), toluidine blue-fuchsine (d). TEM (e-g)