Most organs have specialized jobs, but not the pancreas. This organ has two specialized jobs and straddles both the exocrine and endocrine systems. On one hand, the pancreas is responsible for secreting all types of digestive enzymes into the first part of the small intestine (called the duodenum). On the other hand, the pancreas also secretes insulin, a hormone that regulates blood sugar. In this newsletter, we’ll do a deep dive into this interesting organ.
Contrary to popular belief, digestion mostly happens in your small intestine. Before we go any further, we’ll define digestion: this is the chemical process of breaking food into the building blocks of the four major macromolecules. Protein is broken down into amino acids, starches into sugars, DNA/RNA into nucleic acids, and fats into fatty acids.
While glucose is absorbed directly into the bloodstream in your mouth and your stomach digests some proteins, food enters the duodenum mostly undigested still. Here, it encounters zymogens, a group of proteolytic enzymes, that break down proteins even further. Bile salts, produced by the liver and secreted by the gall bladder, solubilize fats so they can be broken down. Pancreatic amylase and nucleases are responsible for starches and nucleic acid. As the building blocks emerge from this cacophony of enzymatic processes, they are absorbed into your bloodstream and delivered to your liver.
Digestion is only the first part of getting your body the fuel it needs to function. Glucose, the fuel of the mitochondrion, must somehow find its way into cells throughout the body. Since your brain is the biggest and hungriest glucose-gobbler of all time, low glucose levels can lead to fainting, seizures, coma, and death. Unfortunately, glucose is too big to diffuse into cells, and this is where insulin comes in.
After you eat, your liver releases some of the glucose into your bloodstream and your pancreas releases insulin. Insulin acts like a chaperone and helps to transport glucose into the cells. Without insulin, the sugar stays in the blood and is eventually peed out via the kidneys. It’s why diabetes is called “sugar urine disease” in Chinese.
Specialized Cells of the Pancreas
In order to do both jobs, the pancreas is packed with different types of cells. Most of the cells secrete digestive enzymes. About 5% of the cells are called islets of Langerhans and they produce insulin. Type I diabetes is an autoimmune disorder where the immune system destroys the islets and the pancreas can no longer produce insulin. Pancreatic cancer can also destroy islets and block the digestive enzymes from leaving.
Get Your Pancreas On!
Our pancreas necklace celebrates this unique, multi-functional organ. Purchase it for yourself or for a friend. It also makes a great gift for endocrinologists, GI specialists, nurses, and starry-eyed pre-med students.
written by Science with Evie