A hormone is any of a large class of multiprotein signaling molecules in multicellular systems, which are transported from one end of an organ to another in order to regulate physiological function and behavior. Hormones are needed for the proper growth of plants, animals, and sometimes even fungi. Many hormones are secreted by glands and other types of cells throughout the body; the rest is produced by the body itself. Hormones can regulate many functions of the body including the growth, maintenance, and metabolism.
The majority of hormones are secreted by glands, but occasionally they are released into the bloodstream where they act on other parts of the body. Most of these hormones regulate specific bodily functions. Some hormones promote wound healing, help with growth, aid in reproduction and signal the onset of sexual function. There are two types of hormones: primary hormones, which act on external organs; and secondary hormones, which act on internal organs.
Endocrine glands secrete hormones in the blood and throughout the body. Some hormones act directly on the cells, while others are involved in chemical communication with other cells. The most important hormones are estrogen, progesterone, and testosterone, which are released by the ovaries. The production of these hormones is dependent upon the functioning of the pituitary gland, a small organ in the brain that controls the release of hormones.
The function of the pituitary gland is to secrete hormones at a regular time and in a concentrated form. The production of hormones in the endocrine system depends on the need of the organism for energy, growth, and protection. It also regulates the activity of other hormones-and thus the balance of hormones in the body.
All cells in the body-including the skin, brain, muscles, and blood cells-operate under the control of the same hormones. Therefore, when there is a huge need for energy, the hormones are secreted and the cells begin to work-efficiently. However, when there is a huge drop in the levels of the hormones, the cells stop working and the need for energy falls suddenly. This sudden drop can then trigger the secretion of insulin, the hormone that supplies glucose. When there is too much insulin produced, the blood sugar level becomes high and the person becomes obese.
The hormones secreted by the pituitary gland to help regulate the body temperature. If the body temperature becomes too low, then it would be suitable for the hormone-producing glands to stop working. The same goes for the opposite: if the body temperature becomes too high, the glands cannot secrete enough hormones to keep the temperature balanced. Therefore, if the body’s temperature falls below normal, then the hypothalamus sends out a message to the pancreas to secrete insulin to help the body get back to normal temperatures.
Another function of the pituitary gland is the regulation of thyroid activity. When the thyroid gland is secreting too few hormones, the pituitary gland sends a signal to the thyroid to stop producing the appropriate amount of hormones. If the thyroid continues to produce too many hormones, the gland continues to operate inappropriately.
Hormones play a very important role in the metabolism of food. This is because certain hormones-including insulin, thyroxine, and the steroid hormones-control the rate at which the cells of the body divide. When there is an excessive level of one hormone, more cells are divided too quickly, leading to fat accumulation and a general metabolic disorder. However, if the level of another hormone increases, then there is a slower but less complete breakdown of the foods that the body consumes. Hormones play a key role in the normal functioning of the endocrine system, but they also have a vital role to play in the normal functioning of our cells.