[Plate 272, Mucosa and Musculature of Small Intestine]page 145
page 146Characterized by:
Teniae coli: 3 thickened longitudinal bands of muscle (absent from appendix and rectum)
Haustra: sacculations of the colon caused by teniae coli
Appendices epiploicae: fatty lobules of omentum
Cecum
Blind pouch, approximately 7.5 cm in diameter
No mesentery, but may be bound to the abdominal wall by cecal folds of peritoneum
Invaginated by ileum to form the ileocecal valve-does not prevent reflux
Vermiform appendix
Arises from the posteromedial side of cecum
Usually retrocecal
Has a short mesentery from cecum: mesoappendix
Supplied by appendicular artery from ileocolic artery
Vascular supply: ileocolic artery and vein, with lymph to ileocolic nodes
Nerves: sympathetic and parasympathetic nerves from the superior mesenteric plexus
Parasympathetic fibers from vagus nerves
Sympathetic fibers from lower thoracic spinal cord segments
Ascending colon
On right side of posterior abdominal wall
Extends from cecum to liver, where it turns at right colic flexure (hepatic flexure)
Is secondarily retroperitoneal
Vascular supply from branches/tributaries of SMA/SMV
Ileocolic artery and vein
Right colic artery and vein
Lymphatics to epicolic and paracolic nodes
Nerve supply from the superior mesenteric plexus
Transverse colon
Extends from hepatic flexure on the right to splenic flexure on the left
Largest and most mobile section of colon
Attached to posterior abdominal wall by its mesentery: the transverse mesocolon