Pituitary Gland

Illustration showing location and anatomy of the pituitary gland

The pituitary gland (or hypophysis) is situated at the base of the brain about eye level in the centre of the skull and is connected directly by the pituitary stalk to a part of the brain known as the hypothalamus. Operations on the pituitary gland can be performed through the nose, as the pituitary gland rests on top of the nasal cavity.

The pituitary not only has its own activity but also regulates the activity of other glands, acting as the conductor of the endocrine (gland) orchestra. It is no bigger than the size of a walnut. In total the pituitary gland produces nine different hormones.

The human growth hormone is one of these hormones and possibly the most important. If too little of this hormone is produced during childhood, the child’s growth will be stunted and it will be a dwarf. If too much is produced, the child will grow to an abnormal size.

Other hormones stimulate the thyroid gland and the adrenal glands.

Antidiuretic hormone again acts on the kidneys and regulates the balance of water and salts in body fluids.

The follicle stimulating hormone tells the female ovaries and the male testicles when to produce oestrogen and testosterone, and the hormone prolactin stimulates the manufacture of milk in nursing mothers and controls the menstrual cycle.

At the end of pregnancy when the time comes for the child to be born, the pituitary stimulates the muscles in the uterus to contract and start labour.

Adrenocorticotrophic hormone (ACTH) controls the activity of the outer part of the adrenal glands, which sit on top of each kidney.

Melanocyte stimulating hormone (MSH) is produced in the anterior part of the pituitary gland and stimulates melanocytes (skin pigment cells) to produce the black coloured melanin that gives darker colours to skin and hair.

The direct connection of the pituitary gland, and through it the other endocrine glands, to the brain and thus the nervous system is the reason why our mental and emotional states can influence our hormone levels and vice versa. If the pituitary gland malfunctions, the effects can obviously be wide-ranging because of the gland’s importance in so many parts of the body.

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(Last modified: 20th Oct 2014)

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