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Endocrine Pancreas

Pancreatic islet A i - ot-),

B : = p ), and D l =8 ) cells. 1. Reticulum, 2. acini

Superior mesenteric vessels mesentery

low-power section of pancreas 1. Acini, 2. islet, 3. interłobular septum, 4. interłobular duet

ENDOCRINE PHYSIOLOGY

Common bile duet Principal pancreatic duet (Wirsung's>

Accessory pancreatic. duet (Santorini'$)

Figurę 8.18 Structure of the Endocrine Pancreas

The pancreas is both an exocrine and endocrine gland. Its digestive enzymes aro socreted into the duodenum via the pan<reatic duet >ystem, and about 99% o i the cells are exocrine in tunction isee Fig-ures 7.26 and 727). The endocrine portion of the pancreas is tepre-sented by clusters of islei cells (of Langerhans) (lower left micro-graph), a heterogeneous population of cells responsible for the elaboration and secretion of glucagon (a-eells), insulin (/3-cells), and somatostatin (8 cells). Glucagon is a fuef-mobilization hormone (sec

Figurę 8.21). Insulin is a fuektorage hormone (see Figurę 8.20). Somatostatin has a number of actions in the Gl tract; within the islets, rt a< ts on both the «- and /$<elis to suppress glucagon and insulin secretion. A tourth celi type, the F celi (not shown), secretes pancreatic polypeptide, whose primar>’ action is to inhibit the secretion of enzymes and HCO, by the exocrine component of the pancreas.

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