Interpretation of Colonic Biopsies The ability to endoscopically visualize the entire mucosal surface of the large bowel and to biopsy or cytologically sample normal- and abnormal-appearing areas allows clinicians to…
Colitis Due to Venoms Most scorpion and snake venoms contain a mixture of toxic proteins and enzymes that induce circulatory collapse, hemolysis, coagulation abnormalities, and changes in vascular resistance. All…
Changes Induced by Radiographic Substances Barium causes three types of gastrointestinal problems: (a) barium granulomas, (b) bolus obstruction, and (c) an allergic or anaphylactic reaction from the carboxymethylcellulose component of…
Online Chapter 2 CASE 2.1 CLINICAL HISTORY 34-year-old man with fever and abdominal pain. FIGURE 2.1A FIGURE 2.1B FINDINGS Color Doppler ultrasound (US) (A) demonstrates a 3-cm hypoechoic mass in…
Histologic Features The mucosa is smooth and without folds except distally in the rectum. There are no villi. The mucosal surface is flat and regular with interconnected territories containing 10…
Congenital Abnormalities Cecal Agenesis Intestinal agenesis is the failure of a portion of the enteric tube to form. This disorder is rare, occurring in 1 in 50,000 pregnancies. Males are…
Lymphatic Drainage The lymphatics begin as a capillary plexus that wraps around the muscularis mucosae (Fig. 13.10). This plexus sends small branches into the mucosa to reach no higher than…
Gross Features The large intestine is a hollow muscular organ that begins at the ileocecal valve and ends at the anus (Fig. 13.1). It includes the cecum, with the attached…
Blood Supply The cecum, ascending colon, and right part of the transverse colon (midgut-derived structures) are supplied by the superior mesenteric artery via the ileocolic, right colic, and middle colic…
Innervation Like other portions of the gut, the large bowel is innervated by the autonomic nervous system. Parasympathetic nerves stimulate colonic motor activity, whereas sympathetic nerves inhibit motility and decrease…
