Page 638 - Atlas of Histology with Functional Correlations

(11). The cells of a pancreatic islet (3, 7) are illustrated at a higher magnification

in Figures 16.13 and 16.14.

FIGURE 16.12 ■ Exocrine and endocrine pancreas (sectional view). Stain:
hematoxylin and eosin. Low magnification.

FUNCTIONAL CORRELATIONS 16.2 ■ Exocrine

Pancreas

The exocrine and endocrine functions of the pancreas are performed by
separate cells. The pancreas produces digestive enzymes that exit the gland
through a major excretory duct, whereas the hormones produced by the

pancreatic islets are transported from the pancreas via blood vessels.

Both hormones and vagal stimulation regulate pancreatic exocrine
secretions. Two intestinal hormones, secretin and cholecystokinin (CCK),
secreted by the enteroendocrine (DNES) cells in the duodenal mucosa into
the bloodstream, are the principal hormones that regulate exocrine pancreatic

secretions.

The presence of acidic chyme in the small intestine (duodenum)
stimulates the release of the hormone secretin, which, in turn, induces the
exocrine pancreatic cells to produce increased amounts of a watery fluid rich

in sodium bicarbonate ions. This fluid is primarily produced by
centroacinar cells in the pancreatic acini and cells in the intercalated ducts.

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