In order to keep homeostasis within the body, blood sugar must be regulated by a mechanism called blood glucose regulation. When the brain is notified that blood sugar has risen, it sends out a hormone to help regulate and bring down the blood sugar into normal range. This action is known as a negative feedback mechanism, and aids the body's ability to restore equilibrium with the levels of blood glucose circulating in the body. Not only do hormones play a large part in regulating blood glucose, but the brain is also an important component for keeping homeostasis.
Following a meal, carbohydrates are broken down into single monomer sugars called glucose. This sugar — the preferred energy currency for the cells — is transported into the cells through the insulin hormone. When insulin is not functioning properly and the cells do not respond, like in type 2 diabetes, low energy and lethargy may result due to inadequate energy intake from the glucose monomers. Blood sugar, or blood glucose, stays elevated in the body and keeps homeostasis from being achieved.
In healthy individuals, blood glucose regulation involves hundreds of metabolic processes to occur all at the same time. After carbohydrates are broken down into glucose and blood sugar rises, the hypothalamus receives this information. The hypothalamus is the control center of the brain and aids in proper functioning of insulin secretion, which then aids in the intake of glucose into the cells. Insulin is released from the pancreas on the hypothalamus's command and then goes to work on bringing glucose into the cell, thus effectively lowering blood sugar and bringing the levels of blood glucose back into normal range.
When this type of process is occurring, it is usually called a negative feedback mechanism due to the fact that one action aids in bringing a variable back into normal range. Negative feedback is a homeostatic mechanism which occurs in blood glucose regulation to bring back blood glucose, the variable, into normal ranges that are appropriate for the body. Insulin is the hormone which helps to decrease the increasing levels of blood glucose, helping to provide homeostasis within the body.
Blood glucose regulation is mainly controlled by insulin, but it is also directly affected by the brain. The hypothalamus is the control center in the brain which sends a message to secrete insulin. Without proper hypothalamus functioning, insulin would not know when to do its job. There are times when an interference in hypothalamus signaling can cause a disturbance in homeostatic blood glucose regulation, but many times it is able to secrete the necessary hormones to bring variables into normal ranges.