The pancreas has both digestive and hormone-secreting roles. This lesson focuses on the endocrine part of the pancreas: the pancreatic islets and the specialized cells within them.
The pancreas is a long, slender organ located mostly behind the lower half of the stomach. Much of it functions as an exocrine gland, releasing digestive enzymes. Its endocrine function is carried out by clusters of cells called pancreatic islets, formerly known as the islets of Langerhans. Islet hormones enter the blood and help regulate processes throughout the body.
All flashcards
Which islet cells release glucagon, and what is its main effect?
Alpha cells release glucagon, which helps raise blood glucose by promoting glucose release and production in the liver.
How does pancreatic somatostatin affect islet hormone release?
Somatostatin from delta cells inhibits the release of both insulin and glucagon.
What role is pancreatic polypeptide thought to have?
PP cells secrete it; it is thought to contribute to appetite regulation and regulation of pancreatic secretions.
How does insulin support glucose uptake in skeletal muscle and adipose cells?
Insulin signaling promotes movement of glucose-transporter vesicles to the cell membrane, enabling facilitated diffusion into cells.
How do the central mechanisms of type 1 and type 2 diabetes differ?
Type 1 involves autoimmune beta-cell damage and inadequate insulin production; type 2 involves reduced cellular responsiveness to insulin.
Quiz questions
What is glycogenolysis?Answer: Breakdown of glycogen, especially in the liver, to release glucose.
What is a key difference between type 1 and type 2 diabetes?Answer: Type 1 involves autoimmune beta-cell damage; type 2 involves insulin resistance.
Why can very high blood glucose cause excessive urination?Answer: Filtered glucose draws water into the urine, increasing urine volume.
What causes ketoacidosis in a glucose-deficient state?Answer: Accumulation of acidic ketone bodies produced as the body relies more on stored fat.
What happens to glucose-transporter vesicles when insulin signaling is active?Answer: They move to and fuse with the cell membrane, exposing transporters.
Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.