Netter's Gastroenterology

Intestinal Bleeding

Gastrointestinal (GI) bleeding is acute or chronic loss of blood from the upper or lower part GI tract ( Fig. 82.1 ). Acute bleeding may be life threatening, whereas chronic bleeding may be slow or even occult. The GI tract…

Stool Examination

Examination of the stool directly and through microscopy and chemical tests can provide much useful information, although patients, physicians, and laboratories tend to avoid stool evaluation ( Fig. 81.1 ). Open full size image Fig. 81.1 Examination of the Stool.…

Anatomy of the Colon, Rectum, and Anus

The Structure and Histology of the Colon and Sigmoid Colon The large intestine varies in caliber depending on its functional state. Haustra form sacculations that are separated by constricting furrows, so that the lumen bulges and contracts alternately. The caliber…

Carcinoid Syndrome and Neuroendocrine Tumors

Eighty percent of gastrointestinal (GI) neuroendocrine tumors are made up of enterochromaffin-like cell carcinoids, duodenal gastrin G-cell tumors, and rectal trabecular L-cell carcinoids. Less common neuroendocrine tumors are gangliocytic paragangliomas, somatostatinomas, lipomas, and schwannomas. Pathologic study has revealed that the…