The pituitary gland is at the base of the brain, on the midline, hanging from the underside of the hypothalamus by a stalk. It sits in the sella turcica, a hollow in the sphenoid bone of the skull. [1][2]
The 3D brain needs JavaScript. The text below still says where the pituitary gland is and what it does.
Slice
Opens cut by a side (sagittal) slice through the pituitary gland. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Takes part in: hormones — see every part of each lit together.
Where it is
It rests in the hypophyseal fossa of the sphenoid bone, in the centre of the middle cranial fossa, inside a protective bony enclosure called the sella turcica, covered by a fold of dura mater (the diaphragma sellae). [1]
Suspended from the hypothalamus by a stem, the infundibulum or pituitary stalk. [2]
The hypothalamus sits below and in front of the thalamus and narrows to a sharp angle where the pituitary gland is attached. [3]
A single gland on the midline, outside the brain tissue proper: it protrudes from the bottom of the hypothalamus. [1]
What it does
With the hypothalamus it controls much of the body’s endocrine (hormone) system. [1]
The anterior lobe makes and secretes hormones: ACTH (stress response), growth hormone, FSH and LH (reproduction), TSH (metabolic rate) and prolactin (milk production). [1]
The posterior lobe makes no hormones of its own: it stores and releases two made in the hypothalamus, ADH (antidiuretic hormone, for water and salt balance at the kidneys) and oxytocin. [2][1]
Both lobes are controlled by the hypothalamus, but differently: the posterior lobe by nerve fibres, the anterior lobe by releasing hormones carried in a portal blood system. [1]
Connections
Nerve link to the posterior lobe: axons from the supraoptic and paraventricular nuclei of the hypothalamus run down the infundibulum as the hypothalamic–hypophyseal tract and end in the posterior pituitary. [2][1]
Blood link to the anterior lobe: hypothalamic releasing hormones enter capillaries that lead through the stalk to a second capillary bed in the anterior pituitary, the hypophyseal portal system. [1]
Inside it
Two main lobes joined by a small intermediate lobe: the anterior lobe (adenohypophysis), which is glandular, and the posterior lobe (neurohypophysis), which is neural tissue and an extension of the hypothalamus. The intermediate lobe is almost absent in humans. [1]
The lobes have different origins in the embryo: the anterior lobe comes from the lining of the embryo’s mouth (Rathke’s pouch) and migrates toward the brain, while the posterior lobe grows down from the floor of the third ventricle. [1][2]
The pars distalis makes up about 80% of the gland. [1]
Other names
Also called the hypophysis (hypophysis cerebri), from Greek “under” + “to grow”, a name coined by Samuel Thomas von Sömmerring. [1]
“Pituitary” comes from Vesalius’ glandula pituitaria, “gland in which slime (pituita) drips”, from the old belief that it made nasal mucus, disproved in the 17th century. [1]
Size
Oval, about 1 cm across and 0.5 to 1 gram on average, about the size of a kidney bean. [1]
Its height ranges from 5.3 to 7.0 mm and its volume from 200 to 440 mm³. [1]
On this model the pituitary gland measures about 10 mm front to back, 13 mm top to bottom and 12 mm side to side (the box it fits in, not its volume). [4]
Centre of the pituitary gland compared with the centre of the hypothalamus: 5 mm further forward, 13 mm lower; 14 mm apart in a straight line. [4]
Centre of the pituitary gland compared with the centre of the pineal gland: 41 mm further forward, 16 mm lower; 44 mm apart in a straight line. [4]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.