Pituitary: adenohypophysis and neurohypophysis !
- Organ
The pituitary is two glands in one: the front part makes hormones and the back part stores the ones the hypothalamus makes.
Updated 2026-11-01
See it in 3D: Pituitary gland
What it is
The pituitary sits in the sella turcica and joins the hypothalamus through the infundibular stalk. The adenohypophysis comes from oral ectoderm (Rathke's pouch) and is glandular epithelium with acidophils, basophils and chromophobes. The neurohypophysis is nervous tissue: hypothalamic axons that release ADH and oxytocin. The stains and cell types explain pituitary adenomas.
Structure
- Pars distalis on H&E: cords and nests of cells around sinusoidal capillaries; pink acidophils, blue-purple basophils and pale chromophobes.
- Pars intermedia: small colloid-filled cysts, remnants of Rathke's pouch.
- Neurohypophysis: pale, fibrillar look like nervous tissue, with scattered pituicyte nuclei and Herring bodies.
Function
- The adenohypophysis makes GH, prolactin, ACTH, TSH, FSH and LH, governed by hypothalamic releasing and inhibiting hormones.
- Hypothalamic dopamine holds prolactin down tonically.
- The neurohypophysis releases ADH (water reabsorption in the collecting duct) and oxytocin (uterine contraction and milk ejection).
Pituitary cell types
| Cell | Stain | Hormone | Excess (adenoma) or loss |
|---|---|---|---|
| Somatotroph | Acidophil | GH | Gigantism in children, acromegaly in adults |
| Lactotroph | Acidophil | Prolactin | Prolactinoma: galactorrhea, amenorrhea, infertility |
| Corticotroph | Basophil | ACTH | Cushing disease |
| Thyrotroph | Basophil | TSH | Rare thyrotroph adenoma with hyperthyroidism |
| Gonadotroph | Basophil | FSH and LH | Adenomas usually nonfunctioning; hypogonadism if destroyed |
| Neurohypophysis (hypothalamic axons) | Pale, fibrillar | ADH and oxytocin | Central diabetes insipidus if ADH is lost |
Clinical notes
- Nonfunctioning macroadenoma: symptoms from pressure (headache, visual field loss) and loss of other hormones.
- Sheehan syndrome: the pituitary enlarges in pregnancy and can infarct after severe postpartum hemorrhage; failure to lactate is often the first sign.
- A tumour or injury of the stalk can raise prolactin by cutting off the dopamine brake.
Test yourself
Think of the answer, then tap the question to see it.
From which embryonic tissue does the adenohypophysis arise?
From oral ectoderm, via Rathke's pouch; the neurohypophysis comes from the neuroectoderm of the diencephalon.
Which hormones do the acidophils of the adenohypophysis make?
Growth hormone (somatotrophs) and prolactin (lactotrophs).
What are Herring bodies?
Swellings of hypothalamic axons in the neurohypophysis where ADH or oxytocin is stored before release.
Why does a pituitary macroadenoma cause bitemporal hemianopia?
It grows upward and presses on the centre of the optic chiasm, where fibres from the nasal retinas cross.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- Pineal gland and the diffuse endocrine system
- Adrenal cortex zones and medulla
- Thyroid follicles, C cells and parathyroid
- Testis: seminiferous tubules, Sertoli and Leydig cells, spermatogenesis
- Ovary: follicles, ovulation and corpus luteum
Related conditions
Educational content on normal microscopic structure and its clinical relevance; no substitute for studying slides or for a health professional's advice.
Sources: 17.3 The Pituitary Gland and Hypothalamus (OpenStax, Rice University, 2022); Pituitary & Pineal Glands (National Cancer Institute, SEER Training Modules, 2026).
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Representative model, for educational purposes only.