Carl Schroeder, age 13, of Annapolis, Md., for his question:
WHERE IS THE PITUTARY GLAND?
The pituitary gland is the master endcocrine gland of the human body. It is a small bean shaped, reddish gray organ that is located in the saddle shaped depression (sella turcica) in the floor of the skull (the sphenoid bone) and attached to the base of the brain by a stalk. It is located almost at the center of the skull.
The hormones secreted by the pituitary stimulate and control the functioning of almost all the other endocrine glands in the body. Pituitary hormones also promote growth and control the water balance of the body.
The pituitary has two lobes which differ in structure and function: the anterior lobe or adenophypopysis and the posterior lobe or neurohypophysis. The anterior lobe is composed of groups of epithelial cells separated by blood channels. The posterior lobe is composed of nervous connective tissue and nerve like secreting cells. The area between the two lobes is called the intermediate lobe.
One of the most important tasks of the anterior lobe is to stimulate growth. If the lobe is diseased or removed in youth,' a child will not grow properly. The bones of the body do not become longer as in normal growth and there is little increase in body weight.
If the anterior lobe is too active in youth, an individual will grow too much and become a giant. If the gland becomes too active in later life, the jaw, nose and hands will become enlarged.
When the posterior lobe is injured, the kidneys cannot keep back the proper amount of water and excessive urine is formed. This results in a disease called diabetes insipidus. The individual becomes very thirsty.
The intermediate lobe is present only for a short time early in life and during pregnancy and is not known to have any function.
The pituitary gland also makes and releases the hormones that stimulate the sex glands, the thyroid gland and the adrenal glands. Doctors treat diseases and abnormalities caused by the pituitary by giving the patient an extract of the gland or by lowering the activity of the gland through surgery or X ray treatments.
The pituitary gland is only about a third of an inch in diameter. Six hormones are secreted by the anterior portion of the pituitary: growth hormone; corticotropin, which controls secretion of andrenocortical steroid hormones; thyrotropin, which controls secretion of thyroid hormone for metabolism; follicle stimulating hormone, which acts on the ovaries; lutenzing hormone, which also acts on the ovaries; and luteotropic hormone, controlling the growth of the gonads and their reproductive functions.