Insulin and Its Physiological Role
Insulin, a hormone released in the human body by the pancreas, is largely associated in the minds of the public to people affected by diabetes, but little more is known to those outside the healthcare community as to the the importance that insulin plays in the physiology of the human body. This hormone, composed of a protein that is made out of 51 amino acids, the building blocks of organic life, plays a vital role in maintaining bodily homeostasis and is a necessity for sustaining human life (Mantzoros and Shanti).
In order to understand the physiological role of the hormone insulin we must first understand how hormones work in general. Hormones are released by the endocrine system into the blood stream when an aspect of bodily homeostasis has gone out of its range. The blood stream then carries the hormones to target cells in the body that contain hormone specific receptors compatible with a certain hormone or hormones. Once at the target cell, the hormone binds with the receptor and, usually through a number of chemical interactions, acts on a specified metabolic process that either inhibits or excites the process to achieve its intended effect (Sheir, Butler and Lewis 488). Once the hormone’s effect is achieved, impulses are normally triggered within the body which are in turn sent to the central nervous system and interpreted. If the effect of the hormone was enough to alter its metabolic process to the point where homeostasis is achieved, impulses are sent to the organ secreting the hormone telling it to decrease or cease secretion so as not to push the body out of the achieved homeostasis. This process is known as negative feedback, the major control mechanism of hormones in the body, including insulin, which functions to maintain a homeostatic environment in order to support life (Sheir, Butler, and Lewis 489). In having a general understanding of how hormones work, we can now start looking at insulin which interacts with cells in much the same way as hormones do in general.
As stated before, insulin is secreted by the pancreas, the pancreas are in turn made up of three types of cells: alpha, beta and delta cells. Beta cells release insulin into the body while the alpha cells release glucagon, an antagonist of insulin which will be discussed later on, and the delta cells release somatostatin, a hormone which has the ability to inhibit alpha and beta cell secretion in the pancreas (Shier, Butler, and Lewis 516).