anatomy of small and large intestines Flashcards
(54 cards)
where does the jejunum begin
duodenojejunal flexure
where does the ileum end
ileo ceacal junction
how is digestion aided in the small intestine
addition of large amounts of fluid to the chyme
where is the jejunum
upper left abdomen
where is the ileum
lower right abdomen and pelvis
how can you tell the difference between the jejunem and the ileum
gradual change
The jejunum is wider bored,
thicker walled, and redder than the ileum; its wall feels thicker (shirt sleeve through jacket sleeve) because the permanent infoldings of the submucosa, the plicae circulares,
are larger, more numerous, and more closely set in the jejunum, whereas in the upper part
of the ileum they are smaller and more widely separated and in the lower part they are absent
jejunum has fewer arcades with long and infrequent vasa recta
where is the jejunal mesentery attached
post abdominal wall above and to the left of the aorta at L2
fat is deposited near the root and is scanty near the intestinal wall
where is the ileal mesentery attached
Attached below and to the right of the aorta at
the SI joint
fat is deposited through out
what is the name of the lymphoid tissue found in the mucous membrane of the lower ileum
Peyer’s patches
what does the ileocaecal valve consist of
two horizontal folds of mucous
membrane that project around
the orifice of the ileum
it stops colonic contents leaking back into the ileum
where do jejunal and ileal arteries branch from
superior mesenteric artery and its ileocolic branch
where does venous blood from the small intestine drain to
superior mesenteric
vein, which forms the portal vein
where is lymph drainage from the small intestine to
superior mesenteric
nodes, which are situated around the origin
of the SMA
what is the innervation of the small intestine
sympathetic, lesser splanchnic nerve T10
and 11, and parasympathetic (vagus) nerves
via the superior mesenteric plexus
referred pain is peri-umbilical
what is the origin of the SMA
arises from the aorta at L1 and carries nerves (sympathetic) derived from T10 and 11. It supplies the midgut
where are the lacteals
in the centre of each vilus for the absorption of fats and lipids (chyle)
where does the chyle from the lacteals go
cisterna chyli in the upper abdomen . first goes to mesenteric lymph channels that do not pass through lymph nodes but converge on the cisterna chyli
where does lymph from the nodes on the SMA pass to
cysterna chyli
what is meckel’s diverticulum
a remnant of the vitello-intestinal duct and may ulcerate
2 inches long,
2 feet from the end of the ileum, in
2% of people
it may ulcerate, create a fistula or a cyst
symptoms may be similar to appendicitis
how long is the colon
1.5 metres long
what are the internal differences between the small and large intestine
large intestine:
Lacks plicae circularis
Lacks villi
Lacks peyers patches
large intestine is larger in diameter, has omental appendages, 3 taenia coli and haustra
where is the caecum
right iliac fossa
may form recesses adjacent to it
the 3 taeniae coli converge here
covered by peritoneum but does not have a mesentery
where is the appendix
Mc burneys point
1/3 up from ASIS to umbilicus
can be found in many different positions: pelvic; subcaecal;
retrocaecal; retro-ileal; pre-ileal
describe the features of the appendix
a narrow blind ended tube hanging from the caecum
Its submucosa is packed full of lymphoid tissue
It is suspended on a short, but highly variable meso-appendix that transmits
the appendicular vessels
