The pancreas has both exocrine and endocrine functions. The pancreatic islet cell types include alpha cells, which produce glucagon; beta cells, which produce insulin; delta cells, which produce somatostatin; and PP cells, which produce pancreatic polypeptide. Insulin and glucagon are involved in the regulation of glucose metabolism. Insulin is produced by the beta cells in response to high blood glucose levels. It enhances glucose uptake and utilization by target cells, as well as the storage of excess glucose for later use. Dysfunction of the production of insulin or target cell resistance to the effects of insulin causes diabetes mellitus, a disorder characterized by high blood glucose levels. The hormone glucagon is produced and secreted by the alpha cells of the pancreas in response to low blood glucose levels. Glucagon stimulates mechanisms that increase blood glucose levels, such as the catabolism of glycogen into glucose.
alpha cell
pancreatic islet cell type that produces the hormone glucagon
beta cell
pancreatic islet cell type that produces the hormone insulin
delta cell
minor cell type in the pancreas that secretes the hormone somatostatin
diabetes mellitus
condition caused by destruction or dysfunction of the beta cells of the pancreas or cellular resistance to insulin that results in abnormally high blood glucose levels
glucagon
pancreatic hormone that stimulates the catabolism of glycogen to glucose, thereby increasing blood glucose levels
hyperglycemia
abnormally high blood glucose levels
insulin
pancreatic hormone that enhances the cellular uptake and utilization of glucose, thereby decreasing blood glucose levels
pancreas
organ with both exocrine and endocrine functions located posterior to the stomach that is important for digestion and the regulation of blood glucose
pancreatic islets
specialized clusters of pancreatic cells that have endocrine functions; also called islets of Langerhans
PP cell
minor cell type in the pancreas that secretes the hormone pancreatic polypeptide
Visit this link to view an animation describing the location and function of the pancreas. What goes wrong in the function of insulin in type 2 diabetes?
Insulin is overproduced.
1. If an autoimmune disorder targets the alpha cells, production of which hormone would be directly affected?
A) somatostatin
B) pancreatic polypeptide
C) insulin
D) glucagon
D
2. Which of the following statements about insulin is true?
A) Insulin acts as a transport protein, carrying glucose across the cell membrane.
B) Insulin facilitates the movement of intracellular glucose transporters to the cell membrane.
C) Insulin stimulates the breakdown of stored glycogen into glucose.
D) Insulin stimulates the kidneys to reabsorb glucose into the bloodstream.
B
1. What would be the physiological consequence of a disease that destroyed the beta cells of the pancreas?
The beta cells produce the hormone insulin, which is important in the regulation of blood glucose levels. All insulin-dependent cells of the body require insulin in order to take up glucose from the bloodstream. Destruction of the beta cells would result in an inability to produce and secrete insulin, leading to abnormally high blood glucose levels and the disease called type 1 diabetes mellitus.
2. Why is foot care extremely important for people with diabetes mellitus?
Excessive blood glucose levels damage the blood vessels and nerves of the body’s extremities, increasing the risk for injury, infection, and tissue death. Loss of sensation to the feet means that a diabetic patient will not be able to feel foot trauma, such as from ill-fitting shoes. Even minor injuries commonly lead to infection, which , can progress to tissue death without proper care, requiring amputation.