Major Types of Diabetes Mellitus

Hello everyone! Welcome back to our Diabetes Mellitus lecture series. I am Dr. Anku Miglani. Today, we are going to understand the pathogenesis of Diabetes Mellitus—that is, how diabetes actually develops inside the body. Imagine your body as a glucose control room. Every time you eat, glucose enters your bloodstream. Three major players help maintain glucose balance: the pancreas, the liver, and the muscles. Let’s see what happens when this system starts failing. First, meet the pancreas—the insulin control centre. Insulin is secreted by the beta cells of the pancreas. It helps skeletal muscles and adipose tissue take up glucose and signals the liver to reduce glucose production. But what goes wrong in diabetes? Let’s begin with Type 1 diabetes. Here, the immune system mistakenly attacks the pancreatic beta cells. As these cells are destroyed, insulin production falls dramatically, resulting in severe insulin deficiency. This can lead to uncontrolled hyperglycaemia and, in some cases, diabetic ketoacidosis. Now, let’s investigate Type 2 diabetes, where three major mechanisms are involved. Problem number one: insulin resistance. The muscle cells become less responsive to insulin, so they cannot take up glucose as effectively as they should. Problem number two: the liver continues releasing glucose. Even when blood glucose is already high, the liver may continue producing and releasing excess glucose into the bloodstream. Problem number three: pancreatic beta-cell dysfunction. Initially, the pancreas tries to compensate by producing more insulin. However, as beta-cell function progressively deteriorates, insulin secretion becomes insufficient for the body's needs. In addition, increased glucagon secretion and altered incretin effects further contribute to abnormal glucose regulation. The result? Glucose accumulates in the bloodstream, leading to persistent hyperglycaemia. Over time, chronic hyperglycaemia can contribute to damage affecting the blood vessels, eyes, kidneys, and nerves. So, remember this key concept: Type 1 diabetes is primarily characterised by severe insulin deficiency, whereas Type 2 diabetes involves insulin resistance and progressive beta-cell dysfunction. Now that we understand how diabetes develops, let’s explore one of its important complications. In our next lecture, we will discuss Diabetic Foot—what it is, how diabetes damages the nerves and blood supply of the feet, its warning signs, and how this serious complication can be prevented. I’m Dr. Anku Miglani. Don't forget to like, share, and subscribe for more medical lectures. Thank you for watching!