Most of our hormones are secreted constantly with the amount changing as needed. Hormones work by binding with receptors on target cells, hormones can also bind to the inside and outside of the cells. When the hormones bind themselves to the outside of a cell, they can have several different effects, by changing cellular permeability or sending the target cell a message to change enzyme activity inside that cell.
Steroids are a special class of hormones, they are powerful because steroids can bind to sites inside cells. Steroids are shaped like a ringed lipid molecule and can pass easily through the target cell membrane. By being about to pass through the membrane they can interact directly with the cell’s DNA, to change the cells activity.
Understanding how the endocrine system is controlled, we must look at the concept of homeostasis. Most chemical and physical characteristics of the body will have a standard lever or a set point. “Blood pressure, blood oxygen, heart rate, and blood sugar, for example, all have “normal” ranges” (Colbert, Ankney, & Lee. 2011. Pg. ). The control systems are nervous and endocrine, work hard to keep the levels at our ideal levels. There are ways for your body to measure the variable and a place where the “ideal” level is stored, the body has a way to correct the levels that it needs