Adrenal gland: cortex from mesoderm, medulla from neural crest !

Embryonic structure

The adrenal is two glands in one: the cortex, from mesoderm, makes steroids; the medulla, from neural crest, makes adrenaline.

Updated 2026-11-01

See it in 3D: Left adrenal gland · Right adrenal gland · Kidneys

What it is

The adrenal cortex comes from the mesothelium (mesoderm) of the posterior abdominal wall and the medulla from neural crest cells that invade it. The fetal cortex is huge and makes DHEA so the placenta can produce estrogens; it involutes after birth. This dual origin explains why congenital adrenal hyperplasia affects the cortex while neuroblastoma and pheochromocytoma arise from the medulla.

Key facts

Week 5: mesothelium between the root of the mesentery and the developing gonad proliferates and forms the fetal cortex.
A second wave of smaller cells surrounds the first and forms the definitive cortex.
From the second trimester the fetal cortex secretes DHEA, which the placenta converts into estrogens.
After birth the fetal cortex involutes quickly and the gland shrinks.
Neural crest cells invade the medial side and form the medulla (chromaffin cells).
Closeness to the gonad explains ectopic adrenal rests near the testis or ovary.

Structure

Cortex: mesoderm (coelomic epithelium / mesothelium).
Medulla: neural crest; chromaffin cells are modified postganglionic sympathetic neurons without axons.
The medulla receives preganglionic sympathetic fibers directly (splanchnic nerves).

What it becomes

Zona glomerulosa: aldosterone.
Zona fasciculata: cortisol.
Zona reticularis: adrenal androgens; it finishes forming in childhood.
Medulla: epinephrine and norepinephrine released into the blood.
Fetal cortex: DHEA for placental estrogen synthesis.

Markers

SF1 (NR5A1)
CYP21A2
PHOX2B
RET
TH

Clinical notes

Congenital adrenal hyperplasia from 21-hydroxylase deficiency (CYP21A2): low cortisol and aldosterone, excess androgens.
In girls with the classic form: ambiguous external genitalia; in both sexes, a salt-wasting crisis in the first weeks.
Neuroblastoma: a tumor of neural crest neuroblasts, often in the adrenal medulla; typical of infants and young children.
Pheochromocytoma: a chromaffin cell tumor with bouts of hypertension, headache and tachycardia; some are familial (RET and others).

Test yourself

Think of the answer, then tap the question to see it.

Which germ layers do the adrenal cortex and medulla come from?

The cortex from mesoderm (mesothelium); the medulla from neural crest.

What does the fetal adrenal cortex make, and what is it for?

DHEA, which the placenta converts into estrogens during pregnancy.

Which childhood tumor arises from neural crest neuroblasts in the adrenal medulla?

Neuroblastoma.

Why can a girl with 21-hydroxylase deficiency be born with ambiguous genitalia?

Because cortisol precursors are shunted into androgens, which virilize the external genitalia in the fetus.

Add to my cards (4)

See it in 3D

The structures of Durgical's 3D anatomy where it is found.

← All of embryology

Educational content on embryonic development; not a guide to prenatal diagnosis or to medicines in pregnancy and no substitute for a health professional's advice. No doses are given.

Sources: 21-hydroxylase deficiency: MedlinePlus Genetics (U.S. National Library of Medicine, 2024); Neuroblastoma Treatment (PDQ®)–Patient Version (National Cancer Institute, 2024); Langman's Medical Embryology, 13th ed., ch. 18: Central Nervous System (Wolters Kluwer, 2015).

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.