Adrenal and Pancreas Histology Flashcards
What are the cells that the pancreatic islets are derived from?
Endoderm
Where in the pancreas are most of the pancreatic islet cells located?
Slightly more numerous in the tail of the pancreas
What forms the supporting framework for the pancreatic islet cells? What are the other two major components of the supportive framework?
Reticular fibers
ANS fibers
Capillary network
What percent of the pancreas is composed of beta cells? Alphas cells?
70% beta cells
20% alpha cells
Where are the beta cells of the pancreas located? What hormone do these secrete, and what is its function?
Scattered throughout
Secrete insulin to decrease BG levels
Where are the alpha cells of the pancreas located? What hormone do these secrete, and what is its function?
Peripherally
Secrete glucagon to decrease BG levels
Where are the delta cells of the pancreas located? What hormone do these secrete, and what is its function?
Scattered Somatostatin secretion to inhibit: -TSH -GH -Contraction of GI tract and gallbladder
Where are the G cells of the pancreas located? What hormone do these secrete, and what is its function?
Scattered throughout
Gastrin secretion–Stimulates HCl secretion by parietal cells
Where are the PP cells of the pancreas located? What hormone do these secrete, and what is its function?
Scattered
- Pancreatic polypeptide
- Inhibit pancreatic exocrine secretion
Where are the D1 cells of the pancreas located? What hormone do these secrete, and what is its function?
Scattered
VIP to increase motility and stimulates GI fluid secretion
Where are the EC cells of the pancreas located? What 3 hormones do these secrete?
Scattered
Secretes Motilin, substance P, and serotonin
What is the function of Motilin secreted by EC cells of the pancreas?
Promotes gastric and intestinal motility
What is the function of Secretin secreted by EC cells of the pancreas?
Stimulates secretion from the exocrine pancreas
What is the function of Substance P secreted by EC cells of the pancreas?
Neurotransmitter
What is the major neoplasm or symptoms that arises from Beta cells?
Insulinomas that cause hypoglycemia
What is the major neoplasm or symptoms that arises from Alpha cells?
Gluconoma
What is the major neoplasm or symptoms that arises from delta cells?
Somatostatinoma
What is the major neoplasm or symptoms that arises from G cells?
Gastrinoma
What is the major neoplasm or symptoms that arises from PP cells?
Asymptomatic
What is the major neoplasm or symptoms that arises from D1 cells?
Secretory diarrhea
What is the major neoplasm or symptoms that arises from EC cells?
Carcinoid syndrome
True or false: insulinomas are benign
True, but can cause BG to fall below 45 mg/dL
Pancreatic islet cells secrete a lot of proteins. What organelles, then, predominate throughout these cells?
rER
Golgi
What are the structures that hold pancreatic cells together?
Desmosomes
Which type of genetic material is available for transcription: euchromatic or heterochromatic DNA?
Euchromatic
What is the maturation process of insulin?
Proinsulin is secreted into clathrin coated vesicles, where an enzyme cleaves it into insulin and C-peptide
What happens to the vesicles that contain proinsulin as they mature?
Lose clathrin, and gain pumps to increase cell [H+]
What is the MOA of insulin release?
Beta cells take in glucose through GLUT-2, which inhibits K exporter, causing CA influx and release of insulin
What GLUT transporter is found on beta cells of the pancreas? Is this insulin dependent?
GLUT2
Non-insulin dependent