Ileum, Cecum, Apendix

The ileum measure about 12 ft (3.7 m) long ileum ends at the ileocecal junction ileum tends to occupy the lower right part of the abdominal cavity and the pelvic cavity It absorbs mainly vitamin B12 and bile acids, as well as any other remaining nutrients. The ileum joins to the cecum of the large intestine at the ileocecal junction

The coils of ileum are freely mobile and are attached to the posterior abdominal wall by a fan-shaped fold of peritoneum known as the mesentery of the small intestine the ileum is in the lower part of the cavity and in the pelvis The ileum receives numerous short terminal vessels that arise from a series of three or four or even more arcades

Aggregations of lymphoid tissue (Peyer’s patches) are present in the mucous membrane of the lower ileum along the antimesenteric border The lowest part of the ileum is also supplied by the ileocolic artery.

external and internal differences between the jejunum and the ileum

Superior mesenteric artery and its branches

Ileocecal Valve the ileocecal valve consists of two horizontal folds of mucous membrane that project around the orifice of the ileum. plays little or no part in the prevention of reflux of cecal contents into the ileum. The circular muscle of the lower end of the ileum (called the ileocecal sphincter by physiologists) serves as a sphincter and controls the flow of contents from the ileum into the colon.

Stages in the development of the cecum and appendix

Cecum is a blind-ended sac that projects downward in the right iliac region below the ileocecal junction The appendix is a worm-shaped tube that arises from its medial side. Part of large intestine The cecum is often distended with gas and can then be palpated through the anterior abdominal wall in the living patient.

Blood Supply Arteries Anterior and posterior cecal arteries form the ileocolic artery, a branch of the superior mesenteric artery Veins The veins correspond to the arteries and drain into the superior mesenteric vein.

Nerve Supply Branches from the sympathetic and parasympathetic (vagus) nerves form the superior mesenteric plexus

Appendix a narrow, muscular tube containing a large amount of lymphoid tissue It varies in length from 3 to 5 in. (8 to 13 cm). The base is attached to the posteromedial surface of the cecum about 1 in. (2.5 cm) lies in the right iliac fossa, and in relation to the anterior abdominal wall its base is situated one third of the way up the line joining the right anterior superior iliac spine to the umbilicus (McBurney’s point).

Blood Supply Arteries The appendicular artery is a branch of the posterior cecal artery. Veins The appendicular vein drains into the posterior cecal vein.

Nerve Supply is supplied by the sympathetic and parasympathetic (vagus) nerves from the superior mesenteric plexus. Afferent nerve fibers concerned with the conduction of visceral pain from the appendix accompany the sympathetic nerves and enter the spinal cord at the level of the 10th thoracic segment.