The pituitary gland is an endocrine gland about the size of a pea that only weighs a few grams. Another name for the pituitary gland is the Hypophysis. It's location is near the centre of the head, where it hangs from a stalk at the base of the brain. This stalk links the pituitary gland to the Hypothalamus, where hormones are made. Hormones travel through the stalk to the pituitary gland. Some of these hormones are stored until they are needed whilst others trigger the anterior lobe (of the pituitary gland) to produce, then release hormones itself. The gland also secretes hormones that stimulate other endocrine glands, which in turn, also produce and release hormones. Sometimes, benign (non-cancerous) pituitary tumours can remain unnoticed for years, because they do not produce any symptoms. Some of these pituitary tumours do produce symptoms such as headaches and visual problems (this is due to the tumour pressing against the optic nerve). The tumour can cause the gland to stop producing the correct levels of certain hormones. Alternatively, it can cause the gland to over-produce hormones. Pituitary tumours are usually non-hereditary.