Hormones

This past week we talked about hormones. What are hormones anyway? Hormones carry messages from glands to cells to preserve chemical levels in the bloodstream. Hormones move around in the bloodstream waiting to be recognized by a target cell. Each target cell has a receptor that can be activated by only a specific hormone. Once the target cell is activated it then knows to start it's function.
The concentration of hormones depends on three factors. The rate of production, the rate of delivery and the rate of degradation and elimination. Rate of production :: Synthesis and secretion of hormones are the most highly regulated feature of endocrine control. The management of the rate of production is controlled by both positive and negative feed back circuits. The rate of delivery :: An example of delivery would be the blood flow to an organ or a group of target cells. When there is a high blood flow more hormone is delivered and when there is a low blood flow it is the opposite. Meaning there is less amount of hormone delivered. Rate of degradation or elimination :: All hormones have featured rates of decay and are eliminate through one of several different routes. When the secretion of a hormone that has a short half-life gets shut off, the hormone concentration drops. However, when the half-life is long effective concentrations continue for more time after the secretion ceases.
We talked about the two major hormone categories. Those two groups are protein and steroidal hormones. These two groups have many differences. Protein hormones can travel easily through aqueous solutions such as blood. They also bring about rapid and instant changes within target cells. They have a short half-life which means they decompose rapidly. Protein hormones make use of their biological effect on target cells through a second messenger system.
Steroidal hormones must be transported through aqueous solutions with the help of a transport protein. Steroidal hormones like protein hormones also induce changes in target cell nuclei while doing this it alters mRNA transcription. They are hydrophobic which makes then non-polar. Unlike protein hormones, steroidal hormones have a reasonably long half-life.
As humans we need hormones. They help our bodies function and keep us healthy.