PANCREATIC DISORDERS Flashcards
Which pancreatic cells perform an exocrine function?
Acini
Which pancreatic cells perform an endocrine function?
Islets
Which pancreatic islet cells secrete glucagon, and how are they stimulated?
Alpha cells, stimulated by hypoglycemia
What is action and target tissues of glucagon?
Promotes gluconeogenesis and glycogenolysis in the liver
Which pancreatic islet cells secrete insulin, and how are they stimulated?
Beta cells, mainly stimulated by increased blood sugar
Also stimulated by increased glucagon, increased cortisol, certain amino acids, and vagal stimulated (i.e. anticipation of food)
What is the action and target tissues of insulin?
Decreases blood sugar by increasing the expression of insulin-dependent glucose transporters (GLUT4) on skeletal muscle and adipose tissue
What are 5 steps to insulin release?
- Glucose enters beta cells through glucose transporter
- Glucose transformed into ATP
- Closes K+ channels, depolarizes cell
- Ca2+ channels open, trigger insulin release
- 1st phase: stored insulin, 2nd phase: newly synthesized insulin
What hormone do delta islet cells secrete, and what is its function?
Somatostatin, inhibits insulin & glucagon
What hormone do F islet cells secrete, and what is its function?
Pancreatic polypeptide, inhibits somatostatin
Name 5 hormones that increase blood sugar, and 1 hormone that decreases blood sugar
Increase:
1. Growth hormone
2. Catecholamines (e.g. epinephrine)
3. Glucagon
4. Thyroid hormone (T3/T4)
5. Glucocorticoids (e.g. cortisol)
Decrease:
1. Insulin
What are 2 possible causes for hyperinsulinism?
- Congenital islet cell hyperplasia
- Beta cell tumours (insulinomas)
Why do common symptoms of hyperinsulinism include excess sweating, palpitations, nervousness, and decreased LOC?
Symptoms of hypoglycemia
What is an experimental treatment for type 1 diabetes?
Islet cell transplant
How does obesity lead to type 2 diabetes?
Elevated triglycerides interrupt insulin signaling
Name 3 examples of genetic defects that can lead to type 2 diabetes
- Decreased number of insulin receptors on target cells
- Insulin does not cause insertion of GLUT4
- Defective GLUT4
Name 3 reasons why insulin secretion may be impaired, leading to type 2 diabetes
- Abnormal insulin production
- Glucotoxicity: glucose accumulation in beta cells causes apoptosis
- Lipotoxicity: elevated triglycerides creates inflammation, damaging beta cells
What are 2 actions of biguanides and thiazolidinediones?
- Increase glucose uptake
- Inhibit gluconeogenesis
What is the action of secretagogues like sulfonylureas and meglitinides?
Stimulate insulin release
What is the action of alpha-glucosidase inhibitors?
Inhibit carbohydrate digestion and absorption
What is the action of gliflozins?
Inhibit reabsorption of glucose in the kidneys