What Is The Endocrine System?
For your body to function properly and to ensure that homeostasis is maintained, the various parts and organs of the body must communicate with each other. Homeostasis (Greek for staying the same) is what allows the body to remain at equilibrium. One example of homeostasis in action is when we become too hot. The body initiates a number of responses, including sweating. This allows the body to cool down to around 37°C. When we reach this optimum temperature, the sweating stops. Homeostasis is much more complex than this though and doesn’t just try to keep the whole body at its optimum, but also keeps individual cells at their optimum as well.
The nervous system and the endocrine system are important in helping communication within the body. The nervous system allows a rapid transfer (within fractions of seconds) of information, in the form of electrical signals between different parts of the body. Both systems are critical in maintaining homeostasis.
Endocrinology is the science of intercellular (inside cells) and intracellular (between cells) communication. It is the secretion of a chemical substance, or hormone (meaning stimulate, from the Greek word hormaein) into the general circulation, which is able to cause an effect at its target organ. Hormones control growth, development, and metabolism of the body, as well as playing an important role in reproduction.
Hormonal communication relies on the production and release of hormones from various glands in the body, including the pituitary gland, hypothalamus, testes, ovaries, thyroid gland and pancreas. Because the nervous and endocrine systems work hand in hand, these systems are able to complement, and interact with each other. This means that a stimulus from the nervous system can influence the release of hormones and vice versa.
Hormones are rarely secreted at a constant rate. Thus, hormones circulating in the body can undergo fluctuations that may be due to altered secretions of adjustments in metabolism. For example, the concentration of growth hormone varies throughout the day in response to your meals and sleep.
The target cell for a hormone always has a highly specific ‘receptor’ that recognizes a specific chemical message. Once the cell receives that message, a cascade of chemical reactions begins, leading to an alteration in the output of that cell.
References And Further Reading
- Bayliss WM, Starling EH. The mechanism of pancreatic secretion. The Journal of physiology. 1902: 28: 325-353.
- Hiller-Sturmhofel S, Bartke A. The endocrine system: an overview. Alcohol health and research world. 1998: 22: 153-164.
- Rogol AD, Kraemer WJ. The Endocrine System in Sports and Exercise: Blackwell Pub 2005: 647p.
Last reviewed 26/Feb/2014
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