"My substance was not hid from thee, when I was made in secret, and curiously wrought in the lowest parts of the earth. Thine eyes did see my substance, yet being unperfect; and in thy book all my members were written, which in continuance were fashioned, when as yet there was none of them" (Psalm 139:15-16).

David praises God for the marvelous creation of parts of his body that he knew nothing about. Indeed, today we know much more about the parts of the body; and, yet, many praise God less now than then for his wonderful gift of our bodies.

One system that David could know nothing about is the endocrine system. Indeed many people today know very little about this odd assortment of very powerful organs. They are collectively as important as the nervous system in controlling the body. Let's look at how these organs work in the body.

The organs of the endocrine system are all glands; that is, they are able to secrete chemicals that go into the bloodstream and work elsewhere in the body. The chemicals, called hormones, regulate many systems of the body.

In one of those "secret places" David spoke about is the pituitary gland. It is located at the base of the brain attached to the one part of it. This connection between the nervous and endocrine systems allows our brain to control this system. The pituitary is called the "master gland" because it makes chemicals that affect other glands in the body. These chemicals affect everything from how tall we grow to the ability for man and woman to reproduce after their kind. It produces a hormone that controls the production of milk for the newborn baby. The thyroid stimulating hormones control how fast we use up the food we eat. The melanocyte stimulating hormone controls how much pigment we have in our skin cells that cause the different skin colors. The amount of urine released by our kidneys is controlled by the antidiuretic hormone. So we can see the pituitary has far reaching effects for an organ no larger than a marble!

Another of the endocrine glands is the thyroid. It is located in the throat around the voice box. It will produce hormones called T3, T4 and calcitonin. These hormones control metabolism, growth and calcium uptake of the body. Behind the thyroid gland are four little glands called the parathyroid that secretes another hormone called the parathyroid hormone which helps control mineral absorption by the bones.

The adrenal glands, located on top of each kidney, make the chemicals we call adrenaline. The production of adrenaline is critical for our preparation of the "fight or flight" reaction. During danger or extreme excitement, these glands will release adrenaline that causes us to be stronger, faster and more alert than at other times. Our heart rate increases, breathing speeds up, available sugar is readied for quick energy and muscles tense for action. This is the chemical that is responsible for the "hysterical strength" that we sometimes hear about in the media, when incredible feats of strength have been done by individuals who should not have been capable of doing them.

The pancreas works in two different systems of the body. It produces pancreatic juices that aid in the digestion of the foods and produces insulin which is released into the bloodstream to help control the amount of sugar we have.

Problems with this system can cause some very disastrous illnesses. It can lead to dwarfism, gigantism, acromegaly, Cushings syndrome, goiter, Cretinism, Diabetes -- as well as sterility, mental retardation and death. Collectively, this system is about as large as a baseball, but in the powerful effects that the chemicals it produces, its effects are far reaching. Let us always be humbled by the great things that God has done and shown through the creation of our bodies.