Homeostasis control of blood glucose

• Blood glucose concentration is the amount of sugar in our bloodstream, which needs to be kept at a certain level for our cells to function properly.
• Excessive blood glucose levels can damage tissues, hence the need to maintain a fine balance between high and low levels.
• If you eat a really big meal with lots of carbohydrates, these carbohydrates will be broken down into glucose molecules and absorbed into the blood, causing the blood glucose concentration to increase.
• The pancreas, an organ that sits just behind the stomach, releases a hormone called insulin into the bloodstream in response to a rise in blood glucose levels.
• Insulin binds to receptors on certain cells, telling those cells to take in some of the glucose that's floating around in the blood.
• The liver and muscle cells take up most of the extra glucose molecules and combine them together to form glycogen, which is a long-term storage form of glucose.
• As all of this glucose is being removed from the blood, the blood glucose concentration decreases.
• Glucagon, another hormone released from the pancreas, increases blood glucose levels rather than decreases them.
• If blood glucose levels drop too low, the pancreas secretes glucagon into the bloodstream, which binds to liver cells and causes them to break down glycogen into glucose molecules, bringing the blood glucose concentration back up to normal.
• Insulin and glucagon create a negative feedback loop, where glucose levels get too high then insulin is released which causes the glucose to drop down again but if it drops too low then glucagon is released which causes the glucose levels to increase again.
• Our bodies constantly release insulin and glucagon to ensure that the amount of glucose in our bloodstream is always kept around the right levels, which is why our blood glucose concentration constantly changes or fluctuates like this rather than being a flat line.