EXAM #2: ENDOCRINE PANCREAS ANATOMY Flashcards
What are pancreatic islets embryologically derived from?
Endoderm
What hormone is secreted by Beta cells in the pancreas?
Insulin
What hormone is secreted by Alpha cells in the pancreas?
Glucagon
What hormone is secreted by Delta cells in the pancreas?
Somatostatin
What is contained in an immature secretory vesicle of the beta cells? What happens in this vesicle?
Proinsulin, which is cleaved into Insulin and Protein C
How does Clathrin differentiate between an immature vesicle and mature vesicle in the Beta cell?
Immature= clathrin coated Mature= no clathrin
Which has a longer half-life, insulin or protein c?
Protein C
Is GLUT-2 dependent or independent of insulin?
Independent
What is the mechanism of insulin release from the beta cells?
1) Glucose in via GLUT-2
2) Glycolysis increases ATP
3) ATP binds K+ sensitive channel, inactivating it and leading to membrane depolarized (Sulfonylurea Receptor)
3) Ca++ enters voltage gated channels
4) Insulin is released via exocytosis
What drugs target the K+ channel necessary for insulin release?
Sulfonylurea class drugs i.e.
- Gliclazide
- Glimepiride
What transporter is necessary for glucose entry in target cells?
GLUT-4
Is GLUT-4 dependent or independent of insulin?
Dependent
What does insulin do to target cells?
- Causes insertion of GLUT-4 transporters into membrane
- Glucose enters the cell
What is the embryologic origin of the adrenal cortex?
Mesoderm
What is the embryologic origin of the adrenal medulla?
Neural crest cells