Page 190 - Veterinary Histology of Domestic Mammals and Birds, 5th Edition

172 Veterinary Histology of Domestic Mammals and Birds

Adrenal cortex (cortex glandulae suprarenalis) Zona arcuata/glomerulosa
VetBooks.ir The parenchyma of the adrenal cortex comprises cords of In the zona arcuata, the endocrine cells are predominantly
epithelial cells, the surface of which is at least partially in arranged in arcades (Figure 9.13). The cells are weakly
contact with the fenestrated endothelium of cortical sinu-
acidophilic with centrally positioned, heterochromatic
soids. Based on the arrangement of these cellular chains, and frequently irregularly shaped nuclei. The cytoplasm
the adrenal cortex is divided into three, sometimes indis- contains abundant smooth endoplasmic reticulum, mito-
tinctly demarcated, zones (Figures 9.12 to 9.14): chondria and small lipid droplets. The endocrine cells are
surrounded by delicate reticular fibres and lie adjacent
· zona arcuata (zona glomerulosa), to fenestrated capillaries. The organisation of cells into
· zona fasciculata and arcades is observed in carnivores, pigs and horses. In rumi-
· zona reticularis. nants, the cells are arranged in clusters or tufts; in these

9.12 Adrenal gland (ox). The parenchyma of the adrenal gland has two embryonic origins. The cortex is derived
from the mesoderm, the medulla from the neuroectoderm (sympathetic paraganglion). The cortex is divided
into three zones: the zona glomerulosa, zona fasciculata and zona reticularis. Azan stain (x30).

9.13 Zona arcuata of the adrenal cortex (horse). Beneath the connective tissue capsule, the endocrine cells are
arranged in arcades. The mineralocorticoids produced in this region are released into a fine network of capil-
laries, which extends into the zona fasciculata. Azan stain (x360).

Vet Histology.indb 172 16/07/2019 14:59