The endocrine system carries out a wide variety of physiological processes through chemical messengers called "hormones." This system is a collection of glands that produces these hormones, which are necessary for normal bodily functions.
The hormones regulate metabolism, growth and sexual development. These glands release the hormones directly into the bloodstream, where they are transported to organs and tissues throughout the entire body.When functioning properly, the endocrine system, is like a fine-tuned orchestra. Because the endocrine system is comprised of several organs, many functions can go awry. In this section we'll explain the intricacies of the endocrine system and just how you can "make it play" the music you want it to.
The endocrine system consists of the pancreas, thyroid, parathyroid, adrenals, pineal, pituitary and testes/ovaries. The following diagram shows the relationships between these various organs. As you can easily see, these relationships are complex and it takes a skilled clinician to be able to know just what is wrong when looking at the endocrine system. We'll hopefully simplify the complexity as we explain each organ in detail.
Distributed throughout the entire body are, apart from the endocrine glands, also hormone-producing cells and cell groups. Some of the hormones they produce reach their target organs through the bloodstream. Others become effective right at the place of origin.
A whole system of endocrine cells can be found in the gastrointestinal tract. Their hormones stimulate, for instance, the production of digestive juices. In the stomach, gastrin is secreted which stimulates the production of hydrochloric acid. In the duodenum pancreozymin is produced for the stimulation of the enzymes of the pancreas.
In the kidneys are also hormone-producing cells that secrete renin (an enzyme produced in the kidneys) which induces, amongst other things, the release of aldosterone in the adrenal cortex.
While the secretory organs that traditionally make up the human endocrine system, such as the kidney and pancreas, synthesize and secrete specific hormones, studies have revealed that most body tissues may also function as endocrine organs. The growing list includes the lungs, the heart, the skeletal muscles, the uterus, the kidneys, the salivary glands, and the lining of the gastrointestinal tract. Finally, as mentioned above, bundles of nerve cells, called nuclei, have evolved into classical endocrine organs; they secrete neurohormones into the bloodstream.
