Fast Physiology: glucose, glycogen, insulin, and glucagon.

Fast Physiology: glucose, glycogen, insulin, and glucagon.

You’ve heard the terms before, you know they’re important, but what’s the big deal? Here is a user friendly explanation of the hormones, food, and metabolism.

Glucose is a building block of carbohydrates, one of the three macronutrients. Glucose is one of the simplest of sugars that make up most carbohydrates that we eat. So simple that we refer to it as a mono-saccharide, meaning a single sugar molecule.

Let’s say that glucose is like coins. After you eat lasagna, pasta, pizza, and garlic bread, a very carbohydrate heavy meal, glucose fills up your blood, and coins fill up your pocket. But what happens after this meal when you have too many coins in your pocket? You need to store it elsewhere.

Glycogen is excess glucose bonded together in the liver that is used as an energy storage for when glucose levels are low. Glycogen can be exchanging all of the coins for a bill. Easier to store, easier to carry. This bill goes into your wallet, similar to how glycogen is made up of many glucose molecules stored in your liver. But how can you retrieve the money when your pocket is running low on coins? Glycogen is broken down to retrieve glucose by glucagon.

It is always good to have some coins in your pocket, and some glucose in your blood, but when you’re running low, you will need to refill. Glucagon is a hormone made by the body that is signalled to be released when blood glucose levels are low. In our scenario, glucagon is the lightness feeling, telling you that you are low on coins in your pocket. This really happens when you are low in glucose in the blood. You get lightheaded, hungry, and need to bank in those bills for coins!

The opposite of glucagon is insulin, which is released when blood glucose levels are high, and when excess glucose needs to be made into glycogen. Insulin is the only hormone that decreases the amount of glucose in the blood. Insulin here, is the heavy feeling of too many coins in your pocket, signalling the need to exchange the coins to bills.

The body alternates between states of insulin dominated events when blood glucose is too high and glucagon dominated events when blood glucose is too low. It is vital to regulate the body's blood glucose, and the transition from insulin to glucagon regulates glucose levels after and between meals.

Glucose is a source of energy for most cells in the body. It is super important to eat food to keep a store of energy!

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