Large groups of cells are seen in association with some follicles. Where the nuclei are of the same size and staining characteristics, one can conclude that in these sites, the section includes the wall of the follicle (arrows) in a tangential manner without including the lumen.
There are two adrenal glands, one at the upper pole of each kidney. The gland is a composite of two distinct structural and functional components: a cortex and a medulla. The cortex develops from mesoderm and secretes steroid hormones; the medulla develops from neuroectoderm of the neural crest and secretes catecholamines. The adrenal cortex is divided into three zones according to the type and arrangement of its parenchymal cells. These are designated zona glomerulosa, zona fasciculata, and zona reticularis. The zona glomerulosa constitutes 15% of the cortical volume. It secretes mineralocorti-coids (aldosterone and deoxycorticosterone). The zona fasciculata constitutes nearly 80% of the cortical volume. It secretes the glucocorti-coids (cortisol, cortisone, and corticosterone) and a small amount of adrenal androgens. The zona reticularis (5% to 7% of cortical volume) produces most of the adrenal androgens. The zona fasciculata and the zona reticularis are regulated by adrenocorticotropic hormone (ACTH) secreted by the adenohypophysis in response to corticotropin-releasing factor (CRF) produced by the hypothalamus. The zona glomerulosa is not regulated by ACTH but is under feedback control of the renin-angiotensin-aldosterone system that also regulates blood pressure.
Adrenal gland, human, H&E ×45.
This low-magnification micrograph of a section through the partial thickness of an adrenal gland shows the outer capsule (Cap), the cortex (Cort) from one surface of the gland, the underlying medulla (Med ), and a very small portion of the cortex from the other surface of the gland (Cort, bottom center). The cortex has a distinctly different appearance in both structural organization
Cortex, adrenal gland, human, H&E ×180.
This is a higher magnification of a portion of the capsule and the full thickness of the cortex from an area in figure above. The capsule consists of dense connective tissue in which the larger arteries (A) travel to give rise to smaller vessels that will supply the cortex and medulla. The zona glomerulosa (ZG) is located at the outer part of the cortex, immediately under the capsule. The parenchyma of this zone consists of small cells that appear as arching cords or as oval groups of cells.
Cortex, adrenal gland, human, H&E ×245.
This is a higher magnification of the area inscribed by the left rectangle in figure above. It shows the zona glomerulosa (ZG) and the outer portion of the zona fasciculata (ZF). Note the smaller size of the cells in the zona glomerulosa than those in the zona fasciculata. In addition, cells of the zona glomerulosa contain fewer lipid droplets than those of the zona fasciculata.
and staining characteristics. From the inner portion, the medulla, note the lighter appearance of the medullary tissue. A small amount of adipose tissue (AT ) in which the gland is partially embedded is seen at the upper center of the micrograph. The corticomedullary boundary (dashed lines) has a wavelike contour, a reflection of the irregular shape of the gland. Within the medulla are a number of relatively large blood vessels (BV ). These are the adrenomedullary collecting veins that drain both the cortex and the medulla.