Adrenals

The adrenals are a pair of glands, each about the size and shape of a Brazil nut, that cap the upper pole of each kidney. These glands have an outer shell (cortex) and an inner core (medulla). The outside and the in­side parts elaborate distinctly different hor­mones with different functions.

The adrenal medulla elaborates the hor­mone epinephrine, more commonly called by its trade name adrenalin or its nickname, "the emergency hormone." This hormone greatly influences those parts and processes of the body which operate under the con­trol of the autonomic nervous system, with which the adrenal glands have direct con­nection.

Adrenalin is one of the most important chemical mediators between mind and body. Under the stress of danger or excitement, ex­tra quantities of adrenalin are released into the bloodstream. This quickens the heart beat, moblizes energy-releasing sugar into the bloodstream, slows up or stops digestion, sluices blood into the big muscles, dilates the pupils of the eye, and may even cause the hair to stand on end. The purpose of all this is to help the body prepare itself for meeting emergencies by fight or flight.

Dr. Walter Cannon of Harvard, was one of the first to show that the bodily changes which take place under the influence of strong emotions are mediated by adrenalin.

The adrenal cortex produces an entirely different set of hormones, including cortin and cortisone. These adrenal hormones, es­sential to life, help regulate the metabolism of sodium, potassium, and chlorine. Adrenal hormones can also have some effect on sec­ondary sex characteristics. An adrenal tumor, for example, can masculinize a woman and be responsible for her growing a beard. This signifies over function of the gland.

Thyroid

The thyroid gland has two parts, weighing about an ounce apiece, that snuggle up against the front of the windpipe and look something like a small butterfly. This gland secretes a very important hormone called thyroxin. This hormone is concerned with the activity or metabolism of body cells. It helps control the rate at which cells consume oxy­gen and utilize foodstuffs. Too much thyroxin (hyperthroidism) speeds up metabolism; too little (hypothyroidism) slows it down.

Thyroxin is essentially an iodine com­pound, containing about 65% iodine. Defi­ciency of iodine in the body or in the diet makes it impossible for the thyroid gland to elaborate thyroxin adequately. Actually very small amounts of iodine are needed, probably not more than 50 to 100 milligrams a year. Iodine is plentiful in seawater and seafood; it is lacking in the soil of many inland areas. To escape the risk of iodine deficiency in the diet one can use iodized salt. This is common table salt to which a small amount of potassium iodide is added.

Iodine deficiency is associated with en­largement of the thyroid gland, the condition known as goiter. It is also responsible for cre­tinism. A cretin is a dwarfish, misshapen, flat-nosed, often deaf, and usually mentally retarded human creature, born without an adequately functioning thyroid gland. This condition results usually from failure of the child's mother to have a diet adequate in iodine before and during pregnancy. The pre­vention of cretinism lies in making sure that the mother's prenatal diet is adequate in iodine.

Thyroid extract is a dry, powdered sub­stance derived from the glands of meat ani­mals. Since it speeds up metabolism, it is sometimes used as a weight-reducing remedy. It should never be used, however, except un­der the direct supervision of a physician.

Over activity of the thyroid gland (hyper­thyroidism, usually accompanied by goiter) causes patients to lose weight, breathe rapidly, have a fast pulse, often become extremely nervous and excitable, and sometimes have bulging eyes. Relief of this condition may re­quire surgery, cutting away part of the thy­roid gland, or medical treatment with radio­active iodine or drugs that tend to slow down the gland's activity.