Jejunum & Ileum
§ Jejunum and ileum are the 2 distal por4ons of the small intes4ne.
§ They are intraperitoneal.
§ Jejunum is shorter than ileum.
§ Dis4nguishing between jejunum and ileum are important in surgical procedures.
Features of jejunum and ileum:
Jejunum Ileum
§ begins at duodenojejunal flexure § ends at ileocecal junc4on
§ upper part of peritoneal cavity § lower part of peritoneal cavity
(umbilical region) (suprapubic region and pelvis)
§ thick-walled, highly vascular, red in § thin walled, less vascular, pink in
colour colour (pale)
§ wider, empty lumen § narrow lumen
§ mesentery is aHached to posterior § mesentery is aHached below and
abdominal wall, above and leI of right to aorta
aorta
§ translucent windows are not clearly
§ translucent windows are clearly seen due to large amounts of fat
seen due to less amounts of fat
§ shorter and numerous vasa recta
§ longer and fewer vasa recta
§ 3-6 or more arterial arcades
§ 1-2 arterial arcades (arterial loops)
§ circular mucosal folds are less
§ circular mucosal folds (valvulae prominent
conniventes) are larger and thicker
more proximally § shorter villi
§ longer villi § lower part of ileum is dis4nguished
by the presence of Peyer’s patches
§ absent Peyer’s patches (aggregated
lymphoid follicles) § smaller and less numerous plicae
circularis
§ larger and more numerous plicae
circularis
1
§ Jejunum and ileum are the 2 distal por4ons of the small intes4ne.
§ They are intraperitoneal.
§ Jejunum is shorter than ileum.
§ Dis4nguishing between jejunum and ileum are important in surgical procedures.
Features of jejunum and ileum:
Jejunum Ileum
§ begins at duodenojejunal flexure § ends at ileocecal junc4on
§ upper part of peritoneal cavity § lower part of peritoneal cavity
(umbilical region) (suprapubic region and pelvis)
§ thick-walled, highly vascular, red in § thin walled, less vascular, pink in
colour colour (pale)
§ wider, empty lumen § narrow lumen
§ mesentery is aHached to posterior § mesentery is aHached below and
abdominal wall, above and leI of right to aorta
aorta
§ translucent windows are not clearly
§ translucent windows are clearly seen due to large amounts of fat
seen due to less amounts of fat
§ shorter and numerous vasa recta
§ longer and fewer vasa recta
§ 3-6 or more arterial arcades
§ 1-2 arterial arcades (arterial loops)
§ circular mucosal folds are less
§ circular mucosal folds (valvulae prominent
conniventes) are larger and thicker
more proximally § shorter villi
§ longer villi § lower part of ileum is dis4nguished
by the presence of Peyer’s patches
§ absent Peyer’s patches (aggregated
lymphoid follicles) § smaller and less numerous plicae
circularis
§ larger and more numerous plicae
circularis
1
