HypothalamusThe part of the brain above the pituitary. Its neurons make hormones for the posterior lobe and releasing and inhibiting hormones that control the anterior lobe.
InfundibulumThe stem that suspends the pituitary from the hypothalamus. Also called the pituitary stalk.
Anterior pituitaryThe glandular front lobe (adenohypophysis). It makes seven hormones: GH, TSH, ACTH, FSH, LH, prolactin and beta endorphin.
Posterior pituitaryThe neural back lobe (neurohypophysis). It makes no hormones; it stores and releases oxytocin and ADH made in the hypothalamus.
Primary capillary plexusCapillaries at the top of the infundibulum. They pick up the hypothalamus's releasing and inhibiting hormones.
The gland: 4 1
Sella turcicaThe saddle-shaped hollow of the sphenoid bone that the pituitary sits in.
Nerve route to the back lobe: 2 2
Neurosecretory cellsHypothalamic neurons that make the hormones oxytocin and ADH. They send them down their axons.
Hypothalamic-hypophyseal tractThe bundle of axons running from the hypothalamus down the infundibulum. It ends in the posterior pituitary.
Blood route to the front lobe: 4 3
Superior hypophyseal arteryA branch from the carotid arteries. Its branches form the hypophyseal portal system.
Hypophyseal portal veinsThe veins carrying hypothalamic hormones straight to the anterior pituitary. They run from the primary to the secondary capillary plexus.
Secondary capillary plexusCapillaries in the anterior pituitary. They deliver hypothalamic hormones and carry its own hormones away into the circulation.
How this list was compiled: Read 2026-09-26. OpenStax Anatomy and Physiology 2e, section 17.3 The Pituitary Gland and Hypothalamus, https://openstax.org/books/anatomy-and-physiology-2e/pages/17-3-the-pituitary-gland-and-hypothalamus : the hypothalamus anterior and inferior to the thalamus; the pituitary (hypophysis) suspended by the infundibulum (pituitary stalk) and cradled in the sella turcica of the sphenoid bone; the posterior pituitary (neurohypophysis) of neural tissue, the anterior pituitary (adenohypophysis) of glandular tissue; the paraventricular and supraoptic nuclei making oxytocin and ADH, their axons descending as the hypothalamic-hypophyseal tract to axon terminals in the posterior pituitary, which stores and releases but does not make them; the superior hypophyseal artery from the carotids forming the hypophyseal portal system, hypothalamic releasing and inhibiting hormones passing through a primary capillary plexus to portal veins into the anterior pituitary, whose hormones enter a secondary capillary plexus; the seven anterior pituitary hormones (GH, TSH, ACTH, FSH, LH, prolactin, beta endorphin). Licence: own work
The drawing: Drawn for this site by script, 2026-09-26. Own work, nothing traced. Licence: own work
How it works
A pituitary gland diagram labeled with the hypothalamus above it, cut down the middle and drawn far larger than life: the two lobes, the stalk, and the two routes the hypothalamus uses to control them. Start with the 5 main parts.
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The back lobe: a nerve route
Neurosecretory cells in the hypothalamus make oxytocin and ADH. Their axons run down the infundibulum as the hypothalamic-hypophyseal tract, and the posterior pituitary stores the hormones and releases them into the blood.
The front lobe: a blood route
The hypothalamus sends releasing and inhibiting hormones into the primary capillary plexus. The hypophyseal portal veins carry them down to the secondary plexus in the anterior pituitary, which makes its own seven hormones.
Posterior stores, anterior makes: the back lobe only releases what the hypothalamus made.
Questions and answers
What is the difference between the anterior and posterior pituitary?
The anterior pituitary is glandular tissue that makes seven hormones, controlled by hormones from the hypothalamus in the blood. The posterior pituitary is neural tissue that stores and releases oxytocin and ADH made by the hypothalamus.
What is the infundibulum?
The stalk that suspends the pituitary gland from the hypothalamus. The axons to the posterior lobe and the portal veins to the anterior lobe run down it.
What is the hypophyseal portal system?
Blood vessels that carry hypothalamic hormones straight to the anterior pituitary without passing through the general circulation first: a primary capillary plexus, portal veins and a secondary plexus.