Step 1: Pancreatic Islet Structure.
The pancreas comprises endocrine cell clusters known as Islets of Langerhans.
These islets contain four primary cell types: Alpha, Beta, Delta, and F cells.
Step 2: Cell Functions.
- Alpha cells: Secrete glucagon, increasing blood glucose.
- Beta cells: Secrete insulin, decreasing blood glucose.
- Delta cells: Secrete somatostatin, inhibiting insulin and glucagon secretion.
- F cells: Secrete pancreatic polypeptide, regulating pancreatic exocrine function.
Step 3: Insulin's Role.
Insulin is crucial for cellular glucose uptake, glycogen synthesis, and lipid production.
Insulin deficiency or resistance results in diabetes mellitus.
Step 4: Option Analysis.
- (A) Alpha cells: Incorrect. Produce glucagon.
- (B) Beta cells: Correct. Secrete insulin.
- (C) Delta cells: Incorrect. Produce somatostatin.
- (D) F cells: Incorrect. Produce pancreatic polypeptide.
Step 5: Conclusion.
Insulin is secreted by the Beta cells within the islets of Langerhans.