Hormones and the Human Body

Hormones are unique chemical substances that regulate various activities of the cells of your body. They are produced by special organs known as endocrine glands and are released into the blood stream, which carries them throughout the whole body.

Each hormone has the ability to regulate one or more processes taking place within the cells of the body. For example, thyroid hormones increase the cell's ability to burn fuel (such as fat or protein) and produce more energy, while the pancreatic hormone insulin, regulates cellular use of glucose, which helps maintain a uniform sugar level in the blood.

The reason hormones are able to influence cellular function is the presence of special receptors on the surface of each cell. A receptor is similar to a lock, which can be opened by only one particular key and no others.

Each hormone requires its own receptor to be present on the surface of the cell, which is why a typical cell has multiple receptors to accommodate various hormones that the body produces.
After the hormone is synthesized by the endocrine gland, it is first released into the blood. Since the blood circulates throughout the body, it takes the hormone to all the organs and cells. As it encounters new cells, the hormone reacts with their receptors, which causes a specific reaction
within the cells.

When the hormone and the receptor combine, the receptor becomes activated, allowing the hormone or its metabolite to enter the cell. Once inside, it increases or decreases certain specific functions. The combination of endocrine glands and hormones is sometimes called the endocrine system. The main purpose of this system is to provide another way for the brain to regulate body functions. The endocrine system is very closely linked to the nervous system and the main endocrine gland, the hypothalamus, which is actually a part of the brain.

Two additional endocrine glands, the pituitary and the pineal, are located within the brain. Hormones are usually very short-lived substances. They are released into the blood, attach to cellular receptors, get inside the cells and disappear. This is the reason why the levels of most hormones are quite low when measured by blood tests. There are some circumstances
when the levels increase, which also can be measured by testing. In general, blood tests are not very reliable indicators of how much hormone is produced and how well those hormones are working because hormones do not stay in the blood very long, and most of the action takes place inside the cells.

Understanding hormones and how they work in the human body provides better insight to the way our bodies work. They can help us realize when something is seriously wrong or why we may feel different than we normally do. These special indicators can be a very useful tool when they are medically evaluated and taken into consideration for diagnosis.