The Pituitary: A Small Gland With A Big Job
The human body's so-called "Master Gland", the pituitary, is the size of a pea, and weighs just half a gram. It resides at the base of the brain, protected by a small bony structure called the sella turcica, or the turkish saddle of the sphenoid bone. This tiny organ has a very big job to do within the human body. It secretes hormones that stimulate other endocrine glands to perform key bodily functions. It operates with the help of the hypothalamus, which connects it to the brain by a small tube called the Pituitary Stalk.The hypothalamus and the pituitary work as a team to determine how much hormone stimulation the target glands need. The pituitary, despite its size, controls the thyroid, adrenal glands, ovaries and testes. Merck.com reports that the pituitary doesn't produce these hormones continuously. Instead, they are released in short bursts every one to three hours. Some of the hormones, like ACTH, which is growth hormone and prolactin, stimulates a new mother's milk production and maintains the body's immune system follow a circadian rhythm which means the levels rise and fall in the daytime, then peak just before the person wakes up, and drop just before they fall asleep.
There's a front and a back to the pituitary. The posterior or back lobe releases the hormone vasopressin, an anti-diuretic that controls how the kidneys absorb water and oxytocin, a hormone present in women who give birth which helps to speed contractions.
The front or the anterior lobe of the pituitary actually makes a variety of hormones. Prolactin stimulate lactation in nursing women and Melanocyte helps the body produce melanin for the pigmentation of the skin and hair. The Follicle-stimulating hormone determines when hair should grow during development, and human growth hormone controls bone growth to determine height, especially during adolescence.
Many people find themselves to be suffering from disorders of the pituitary gland. Most frequently these are caused by pituitary gland tumors. The Endocrine Society reports that these are fairly common in adults but are usually not brain tumors of a form of cancer. A pituitary gland tumor can, however, interfere with the normal formation and release of hormones in the body.
There are three general categories that pituitary gland tumors fall into:
When the tumor causes too much of any hormone to be released into the body. Many tumors wind up making too much prolactin, the hormone that triggers milk production in new mothers. Or, tumors can also produce excess growth hormone, or too much of the hormone that stimulates the thyroid.
When the pituitary is secreting too little of the hormones that it is supposed to distribute. This can sometimes be caused by an overly large tumor, or during the attempt to do surgery or radiate the tumor.
A growing pituitary gland tumor can press against the normal pituitary gland or other areas in the brain, causing headaches, vision problems, or other ill health effects. Injuries, certain drugs, and other conditions can also hurt the pituitary gland. Doctors say that major head trauma can definitely create a loss of normal pituitary function.
