Mesntery Flashcards
what is the mesentery ?
double fold of peritoneal tissue that suspends the small intestine and large intestine from the posterior abdominal wall.
is the mesentery an organ?
yes
functions of the mesentery
Suspends the small and large intestine from the posterior abdominal wall; anchoring them in place, whilst still allowing some movement.
Provides a conduit for blood vessels, nerves and lymphatic vessels.
Postulated to play a pathological role in inflammatory diseases such as Crohn’s disease.
desribe the lymphatics of the mesentery
The mesentery contains both lymph nodes and lymphatic vessels. There are several groups of lymph nodes found within the mesentery:
Inferior mesenteric lymph nodes – receives lymph from the hindgut organs, and drains into the superior mesenteric lymph nodes.
Superior mesenteric lymph nodes – receives lymph from the midgut organs (and from the inferior mesenteric nodes), and drains into the pre-aortic lymph nodes.
descibe the innervation of the mesentery
the superior mesenteric plexus (a continuation of the celiac plexus) accompanies the superior mesenteric artery into the mesentery.
The superior mesenteric plexus then divides into many secondary plexuses which contain parasympathetic and sympathetic innervation to the mesentery associated with a particular organ, the organs themselves and their related blood vessels.
what acts a conduit for neurovascuar structures
the mesentary
what is the venous drainage of the mesentry?
The venous drainage of the mesentery is via the superior mesenteric vein (SMV) and inferior mesenteric vein (IMV), which both run alongside their associated arteries.
what is the arterial supply of the mesentry
The superior and inferior mesenteric arteries (SMA and IMA) arise from the abdominal aorta and travel in the mesentery to supply the abdominal viscera. These vessels also give rise to branches that supply the mesentery itself.
Superior mesenteric artery – supplies the organs of the midgut – from the major duodenal papilla to the proximal two thirds of the transverse colon.
Inferior mesenteric artery – supplies the organs of the hindgut – the distal one third of the transverse colon, splenic flexure, descending colon, sigmoid colon and rectum.
desribe the structure of the mesentery
The mesentery is formed by a double layered fold of peritoneum.
where is the root of the mesentery
point where the mesentery attaches to the posterior abdominal wall, and is therefore a ‘bare area’. Due to the range of abdominal organs the mesentery envelopes, the root is long, narrow and has an oblique orientation, from the left side of the L2 vertebra to the right sacroiliac junction roughly.
what are the different flexures used to mark the distinction between different portions of the mesentery:
there are six flexures of note: duodenojejunal, ileocaecal, hepatic, splenic, and those between the descending and sigmoid colon and the sigmoid and rectum
what are the specific flextures and what do they connect
Mesentery of the small intestine – connects the loops of jejunum and ileum to the posterior abdominal wall and is a mobile structure. (1)
Right mesocolon – flattened against the posterior abdominal wall (2)
Transverse mesocolon – a mobile structure and lies between the colic flexures (3)
Left mesocolon – flattened against the posterior abdominal wall (4)
Mesosigmoid – has a medial portion which is flattened against the posterior abdominal wall, whereas the region of mesentery associated with the sigmoid colon itself is mobile. (5)
Mesorectum – assists in anchoring the rectum through the pelvis.(6)
what is the Told’ts facis
The areas of the mesentery that are flattened against the posterior abdominal wall (the right and left mesocolon and the medial mesosigmoid) are attached to the abdominal wall via an additional layer of connective tissue known as Toldt’s fascia. The fascia contains several lymphatic channels.
