THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -A (alpha) cells-these cells secrete glucagon and constitute 15-20% of the islet cells. They are usually larger than B cells and most commonly located peripherally in the islet. Their granules are more uniform in size, with a larger dark center surrounded by a thinner halo compared to B cells.

Detailed explanation-2: -The islets of Langerhans are endocrine functional units of the pancreas. Histologically, four cell types can be identified: the or A cells that secrete glucagon; the or B cells that secrete insulin; the or D cells that secrete somatostatin; and the PP cells that secrete pancreatic polypeptide.