The axons of these neurons run down the pituitary stalk to terminate on the capillary bed of the posterior lobe. The terminals are separated and grouped by glial cells, the pituicytes. The axons of the hormone producing cells can be seen to contain numerous small clear vesicles, and larger dense core vesicles. Clinical Anatomy Upward growth of pituitary tumors may press on the optic chiasma. Typical visual field defects would be bitemporal hemianopia, and upper quadrantopia.
Tumors can grow up into the third ventricle causing hydrocephalus.
Rapid lateral expansion, perhaps due to haemorrhage may compress the third, fourth or sixth cranial nerves. Headache may be present from stretch of the meninges. Surgery to remove pituitary tumors is usually performed through the sphenoidal sinus.