Adrenal Gland Anatomy
Functional Zonation (The “GFR” Layers)
| Zone | Product | Regulation |
|---|---|---|
| Zona Glomerulosa | Aldosterone | RAAS (Angiotensin II) & K+ |
| Zona Fasciculata | Cortisol | ACTH / CRH |
| Zona Reticularis | Androgens (DHEA) | ACTH |
NEET PG “Must-Know” Pearls
- Embryology: Cortex is from mesoderm; Medulla is from neural crest.
- Medullary Physiology: Chromaffin cells are modified postganglionic sympathetic neurons. They secrete Epinephrine/Norepinephrine in response to preganglionic acetylcholine.
- Enzyme Regulation: The enzyme PNMT (converts norepinephrine to epinephrine) is induced by high concentrations of cortisol received via the portal venous system from the cortex.
- Blood Supply: Supplied by superior, middle, and inferior suprarenal arteries (branches of the inferior phrenic, abdominal aorta, and renal artery, respectively).