Type 1 diabetes makes up around 10% of all cases of diabetes. Type 2 diabetes, where insulin does not function properly, makes up the other 90%.
In a normal situation, blood sugar levels are kept in check through the release of the hormone insulin when glucose levels in the blood rise. Insulin allows cells to tka eup glucose and use it as fuel. Insulin acts as a key to a lock that is present on cells. When the lock is unlocked, a door upon through which glucose can enter the cell.
In type 1 diabetes, the insulin producing cells in the pancreas are destroyed by the bodies own immune cells. Therefore, insufficient insulin is released when blood sugar levels rise. Without insulin, the door allowing glucose to enter the cell remains closed. A build up of glucose that can not enter the cells will cause the symptoms connected to type 1 diabetes.