Compare and contrast two such stabilizing mechanisms in humans that are under hormonal control and two that are not.

Question

In order to remain healthy, humans must be able to keep their bodies in a stable condition even when the outside environment is very different. Sometimes hormones are used to accomplish this but sometimes they are not. Compare and contrast two such stabilizing mechanisms in humans that are under hormonal control and two that are not.

Answer 1

I find it a bit unclear whether the question is asking to compare non hormonal stabilizing mechanisms to hormonal stabilizing mechanisms or if it's asking to compare each specific example with one another. So I answered both.

One hormonal feedback loop is blood sugar regulation. When blood sugar gets too high, the body releases insulin in response, the hormone insulin targets body cells and triggers them to take up sugar. This lowers the blood sugar and homeostasis is maintained. Another hormonal stabilizing mechanism are ADH levels in the kidneys. ADH or Antidiuretic Hormone is released when fluid levels in your body drop (you're thirsty). The purpose of ADH is to lower the amount you urinate by having the blood reabsorb more water from your kidneys. ADH is released from the pituitary gland and targets a key location in the kidney. The kidney then retains more water, causing you to urinate less and reserve water in your bloodstream.

Both of these mechanisms use hormones to stabilize your body. In both of these cases, once the condition is stabilized (be it blood sugar or volume of fluid) the mechanism stops. They both control amounts of a certain substance in your blood, they both travel through the blood, they both target body cells, and they both are negative feedback loops. One major difference is that insulin targets nearly every body cell, while ADH targets a specific group of cells. Another difference is insulin is excreted by the pancreas while ADH is excreted by the pituitary gland.

Stabalizing mechanisms in the human body that aren't controlled by hormones are usually controlled by some other chemical or via the nervous system. They're also harder to identify because most body functions involve hormones at SOME point when reacting to something. One example would be, when you exercise the Carbon Dioxide rises in your blood (in the form of bicarbonate). You're brain detects this change and tells your lungs to breath more rapidly and your heart to beat more rapidly. This increases the gas exchange in your circulatory system and ideally lowers the carbon dioxide levels in your body. Another example would be reaction to pain. If you'd place your hand on a hot stove, you remove it immediately in response so the heat does not do damage to your skin cells and destabilize your body system. This response does not involve hormones simply because you need to react more quickly than hormones can travel. Instead, it is a nervous system reflex and the message is transmitted through the nervous system rather than through the endocrine system.

These two responses are similar in that they work faster than the endocrine system does and they use the nervous system. They are different in that one uses chemical concentration in the blood stream to start the stabilization while the other uses exclusively neurological impulses (action potentials.)

In general, if you need a quick response it will be a non hormonal stabilizing mechanism and if your body can spare a few seconds it tends to use a hormonal stabilizing mechanism. Hormones move slower than action potentials, but they can effect more of the body at once. However, they are both used to relay information and instigate a response. I hope this helped! Let me know if I went into too much or too little detail.