Adrenal Glands
- secrete both steroid hormones and catecholamines
- steroid secreting portion
- beneath capsule
- 90% of weight of gland
Development
- derived from mesodermal mesenchyme
- closely packed ovoid clusters and curved columns continuous with cords of
zona fasciculata
- closely packed nuclei stain densely
- rich network of capillaries
- abundant smooth ER, multiple Golgi complexes, large mitochondria with
shelf-like cristae, free ribosomes, some rER,
- Sparse lipid droplets
- secretes mineralocorticoids, e.g. aldosterone
zona fasciculata
- large polyhedral cells
- arranged in long straight cords seperated by sinusoidal cappillaries
- lightly staining spherical nucleus
- numerous lipid droplets
- even more sER, mitochondria with tubular cristae, well developed
Golgi complex and some rER
- secretes glucocoricoids e.g. hydrocortisone (cortisol)
zona reticularis
- small cells, densely staing nuclei arranged in anastomosing cords
- few lipid droplets, well developed sER, numerous cristae with tubular
cristae, little rER
- principal secretion are weak androgens e.g. dehydroepiandrosterone (DHEA)
and some glucocorticoids (hydrocortisone)
- catecholamine secreting portion
- deep to the cortex
Development
- derived from neural crest cells
Microscopic structure
- large, pale staining cells (chromaffin cells)
- numerous membrane bound secretory granules, rER and well developed Golgi
- dense core granules exist in noradrenaline secreting cells
- adrenaline secreting cells have less dense granules
Innervation
- release of granules by ACh by preganglionic sympathetic neurons that
synapse on each cell
Capsule
- covered by a fibrous capsule
| development of cortex and medulla; foetal zone of cortex |
| gross and microscopic structure of adrenal cortex and
medulla; vasculature, innervation |
|