Endocrine Pancreas & Liver

Question 1

List cells of islets of Langerhans

Answer 1

1. A, B, D cells, main cell types , 95%
2. PP(F), D-1, EC cells , minor cell types, 5%

Question 2

Types of cells of islets of Langerhans are differentiated by……

Answer 2

TEM/immunohistochemistry

Question 3

Mention percentage, location & hormone of:
1. A cells
2. B cells
3. D cells

Answer 3

1. 15-20%, peripherally, glucagon
2. 60-70%, central, insulin
3. 5-10%, scattered less abundant, somatostatin that inhibit insulin, glucagon & GH

Question 4

Hormone secreted by F cells & its function

Answer 4

Pancreatic polypeptide
Stimulate enzymes released by gastric chief cells, inhibit intestinal motility & bile secretion, & inhibit pancreatic enzymes secretion

Question 5

Hormone secreted by D1 cells & its function

Answer 5

VIP
Similar to glucagon, also affect gut motility & secretion & stimulate pancreatic exocrine secretion.

Question 6

Hormone secreted by EC cells & its function

Answer 6

Motilin, secretin, substance P
M, stimulate gastric & intestinal motility
S, stimulate bicarbonate & enzyme secretion in pancreas
P, has neurotransmitter properties

Question 7

Describe paracrine regulation of islets cells

Answer 7

They are linked by gap junctions allowing lateral diffusion of signaling molecules
Glucagon stimulate insulin release
Insulin inhibit glucagon release
Somatostatin inhibits both

Question 8

Describe autonomic regulation of islets cells

Answer 8

1. 10% of islet cells have close association with sympathetic & parasympathetic nerves
2. Presence of gap junctions allows spread of these signals to islet cells
3. Sympathtic inc glucagon & dec insulin which glucagon has opposite effect

Question 9

…….stimulate exocrine secretion while……inhibit it.

Answer 9

Insulin, VIP
Glucagon, pancreatic polypeptide, somatostatin

Question 10

Tranferrin is a…..

Answer 10

Glycoprotein