Diabetes mellitus is a family of metabolic disorders caused by defects in the pa
ID: 94741 • Letter: D
Question
Diabetes mellitus is a family of metabolic disorders caused by defects in the pathways that regulate the homeostasis of glucose levels. The most common forms are: Type 1 diabetes mellitus: Specialized cells in the pancreas don't make enough of the protein hormone insulin, which triggers target cells to take in glucose from the blood. Type 2 diabetes mellitus: Insulin is present at normal (or above normal) levels, but the normal target cells stop responding normally to the hormone. In which type of diabetes are the target cells' signaling pathways for insulin more likely to be defective? Would you expect a target cell's insulin receptors to be on the cell surface or within the cell? Why can't glucose simply leak into cells when its concentration in the blood is higher than its concentration inside cells? Normally, when blood glucose levels fall, insulin release from the specialized pancreatic cells decreases. What kind of feedback loop is operating here?Explanation / Answer
1-In type 2 diabetes mellitus,the Signaling pathways for Insulin in target cells is defective.This is also known as Resistance to Insulin.Hence Insulin level in the body is Normal or sometimes above Normal due to Feedback but since the Receptors for Insulin are not functioning properly,Glucose can't enter cells from blood which causes a raised blood glucose levels(Hyperglycemia).
2-The Receptors for Insulin are present on the Cell Surface of Target Cells (not within the cells).
3-This is because the entry of Glucose into the body cells is only facilitated with the help of Insulin hormone since it happens by GLUT(Glucose Transporters),not by Simple diffusion.
4-This kind of feedback loop is called a Negative feedback,where a Fall in blood glucose levels supresses Insulin release.