It is controlled both reflexly and voluntarily. Copyright Urban & Fischer Verlag. The colon in the cat is essentially the same as in the dog (Figure 7-65), except the ascending colon may be proportionally shorter. Serum amyloid A concentrations may be useful for monitoring the response to treatment and optimal time to cease therapy. It is characterized by an S shape of variable length, a short mesentery, and therefore good mobility. Early-stage cancers may require only a small section of the colon to be removed during colectomy. These folds are termed anal valves. The middle and inferior rectums drain via middle and inferior rectal arteries, which empty directly into the systemic circulation. It is characterized by fusion of the teniae into the complete longitudinal muscle layer of the rectum and by an abrupt loss of appendices epiploicae. 4.3). Complications with trocarization include peritonitis and local abscessation. In the ventral colon, the site of bacterial fermentation, the teniae have a greater proportion of elastin than in the dorsal colon. The colon in the cat often contains fecal material and is rarely completely empty. The descending colon continues through the pelvic canal as the rectum (Figures 7-59 and 7-60). The other difference in the feline large bowel, as noted previously, is the less developed cecum and the lack of a distinct cecocolic valve. The sigmoid colon may be in close contact with the urinary bladder, the ventral surface of the upper rectum, or, in females, the uterus and annexes. The ascending colon extends up from the cecum at the level of the ileocecal valve to the bend in the colon called the hepatic flexure, which is located beneath and behind the right lobe of the liver; behind, it is in contact with the rear abdominal…. Changes in the neural elements within the intestinal wall have also been described in NEC. The ascending colon measures 10 to 20 cm and lies within the anterior pararenal space. A blocked colon is an emergency that may require total or partial colectomy, depending on the situation. Here are some useful Descending colon photos that help show a pictorial impression of the organ. Just caudal to the pylorus, the colon turns to the left at the right colic flexure and then courses transversely across the abdomen, cranial to the root of the mesentery, as the transverse colon. The descending colon first passes the lateral border of the left kidney and then curves medially, reaching the pelvic rim. In these instances, peristalsis of the wall might be present and appear as multifocal regions of circumferential narrowing; this is a normal appearance and is not necessarily evidence for spasticity (Figure 7-62). perineal hernia). The transition from the left to the right ventral colon forms the sternal flexure, and the transition from the left to the right dorsal colon forms the diaphragmatic flexure. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. The colon is also innervated by adrenergic sympathetic nerves from the lower thoracic and upper lumbar segments of the spinal cord. Denise Tiran MSc, PGCEA, RM, RGN, ADM, ... Maggie Evans RM, RN, HV Cert, MSc (Complementary Therapies), in Reflexology in Pregnancy and Childbirth, 2010. 2). The transverse colon is entirely intraperitoneal with the exception of its right end, which is in close contact with the duodenum and the pancreas. The lumen of the colon becomes narrower towards the rectum. It begins at a region where the rectum suddenly becomes narrower. Excitatory cholinergic neurones are also present in the ganglia of the submucosal and myenteric intramural plexi. Cecal tympany commonly accompanies obstructions of the ascending colon because of cecal outflow obstruction. Other articles where Ascending colon is discussed: human digestive system: Anatomy: The ascending colon extends up from the cecum at the level of the ileocecal valve to the bend in the colon called the hepatic flexure, which is located beneath and behind the right lobe of the liver; behind, it is in contact with the rear abdominal… The adjacent peritoneum forms the paracolic gutters just lateral to the ascending and descending colon. The normal canine colon can also be primarily empty, containing only gas. The small intestines curl round in a clockwise direction inside the boundaries of the large intestines.