The pituitary gland lies deep inside the head. It's often called the "master gland" because it controls many of the things other glands do.

Just above the pituitary is the hypothalamus. It sends hormonal or electrical signals to the pituitary. These determine which hormones the pituitary will release.

For example, the hypothalamus might send a hormone called GHRH, or growth hormone releasing hormone. That would trigger the pituitary's release of growth hormone, which affects the size of both muscle and bone.

How important is this? Not getting enough during childhood can cause pituitary dwarfism. Getting too much can cause the opposite condition called gigantism. In a body that has already matured, too much growth hormone can cause acromegaly. With this condition, facial features become rough and course; the voice becomes deeper; and hand, foot, and skull size expand.

A different hormonal command from the hypothalamus might trigger the release of thyroid stimulating hormone or TSH. TSH causes the thyroid to release two hormones called T3 and T4 that stimulate metabolism in other cells throughout the body.

The pituitary can also release a hormone called antidiuretic hormone, or ADH. It's produced in the hypothalamus and stored in the pituitary. ADH affects the production of urine. When it's released, the kidneys absorb more of the fluid that passes through them. That means less urine is produced.

Alcohol inhibits the release of ADH, so drinking alcoholic beverages results in more urine production.

The pituitary gland produces other hormones that control other bodily functions and processes.

For instance, follicle stimulating hormone, or FSH, and luteinizing hormone, or LH, are hormones that affect the ovaries and egg production in women. In men, they affect the testes and sperm production.

Prolactin is a hormone that affects breast tissue in nursing mothers.

ACTH or adrenocorticotrophic hormone causes the adrenal glands to produce important substances similar to steroids.

Growth, puberty, baldness, even sensations like hunger and thirst, are just a few of the processes that are influenced by the endocrine system.