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Current time:0:00Total duration:7:44

Pathophysiology - Type II diabetes

Video transcript

diabetes mellitus is a group of disorders that's caused by improper function of insulin which is a hormone produced by the pancreas and insulin is responsible for helping regulate blood sugar or glucose levels in the blood now since it's a group of diseases there are actually multiple different underlying causes of diabetes mellitus and one of these causes is known as type 2 diabetes now before we dive in to the actual cause of type 2 diabetes let's first get a better understanding of how exactly insulin works and there are two major steps so imagine that you just ate a big meal maybe like a bowl of pasta or something and your body is currently absorbing all of those nutrients from your digestive system into your bloodstream now one of these nutrients is glucose and as your body absorbs it that glucose starts building up in the bloodstream and in this feeding or absorptive state your body wants to store this glucose in places like the liver and muscle cells so that it can be used for energy later when the body needs it but unfortunately glucose on its own can't get into these cells in a sense these cells are locked but fortunately the pancreas is able to help with this problem so there are a couple types of cells in the pancreas that sense blood sugar levels and these cells are located in the islets of langerhans and these green cells here and the islets of Langerhans are meant to represent the beta cells and when the blood glucose increases the beta cells of the pancreas sense this change and they secrete a hormone known as insulin into the blood and what insulin does is it acts like a key that can unlock these cells so that the glucose can be stored in both the liver and the muscle cells so you can see that there are two steps in order for insulin to function properly and the first is that this these beta cells of the endocrine portion of the pancreas have to be functioning in order to secrete the insulin into the blood and then second these cells have to respond to the insulin in order to unlock them so that the glucose can be taken out of the blood to decrease the blood glucose levels now diabetes mellitus can be caused by dysfunction at either of these two steps so if the beta cells aren't functioning properly or they're being destroyed such as as in type one diabetes there isn't enough insulin to be produced unlock the cells and what happens is that the glucose builds up in the bloodstream and that person will develop diabetes mellitus however similarly in step two if the cells aren't properly responding to the insulin in the blood then they can't be unlocked and the glucose will build up in the blood vessels and you'll get hyperglycemia and the person will develop diabetes mellitus so this is what I met earlier when I said that diabetes is a group of disorders because multiple different mechanisms can result in diabetes mellitus so in general type-2 diabetes is caused by dysfunction of this second step and this is known as insulin resistance so in type 2 diabetes the beta cells of the pake of the pancreas are functioning properly and they're able to produce insulin but that insulin isn't able to have its proper effect on the cells throughout the body however it is important to note that as the disease does progress the pancreas can become effective and eventually decrease its insulin production but in general type 2 diabetes is thought of as primarily due to this insulin resistance so what exactly causes the cells to become resistant to insulin well unfortunately there's no simple answer to this and the cause of type 2 diabetes is very complex and it includes many different factors that work together to cause the problem so let's get a little bit better idea of this I'm going to just erase some of our work here so we can get a little more room so what are some of these risk factors well one of the most important ones is actually genetics in fact having a family history say in someone's parents or grandparents of type 2 diabetes is one of the biggest risk factors for developing type 2 diabetes other factors include obesity hypertension and increasing age and it's the interaction of all these different factors plus more that end up resulting in insulin resistance but how can we maybe understand this a little bit better well one of the factors that we understand maybe a little bit better than some of the others is the effect of obesity so let's bring back that lock I described earlier so if you think of obesity as kind of this perpetual feeding state or in a sense that the body is continuously being exposed to insulin release by the pancreas in an effort to bring down the increased glucose from this perpetual feeding state over time the receptors on the cells or these locks become desensitized to the insulin and they become resistant to its effect so let's use an analogy to help understand this idea of resistance so instead of a lock pretend this is a person and this person decides to put on a baseball cap so when you first put on a baseball cap you can feel it on your head however over time say 10 15 minutes this constant stimulation of the touch receptors results in a desensitization to the feeling of the ball cap on your head and it feels like it's no longer there so this is kind of similar to the cells in the body if they're constantly exposed to this insulin they'll stop responding to it and the cell won't become unlocked now initially the pancreas is able to compensate it for this resistance by producing more insulin however eventually as time progresses the pancreas cannot keep up to overcome the insulin resistance and eventually the body will lose its ability to lower the blood glucose level with insulin and this will result in hyperglycemia and the complications that are associated with it but this process can take time in fact from the time this insulin resistance starts to when someone would develop some symptoms of type 2 diabetes can actually take multiple years but at the same time early diagnosis and treatment is critical to prevent the serious complications associated with diabetes and for this reason it's very important to screen people who are at risk who people who have some of these risk factors it's important to screen them for type 2 diabetes so they should regularly have their blood glucose levels monitored for hyperglycemia so that they can be detected and treatment can be started even before he or she will develop symptoms so I hope this gives you a better understanding of what causes type 2 diabetes it's not caused by a problem with the pancreas itself and the ability to produce insulin instead it's caused by this insulin resistance by the cells throughout the body that are supposed to respond to insulin