digestive system anatomy Flashcards
foregut contains
oesophagus, stomach, liver, pancreas, proximal half of duodenum
midgut contains
distal half of duodenum, jejunum, ileum, caecum, 3/4 transverse colon
hindgut contains
1/4 transverse + descending + sigmoid colon, rectum
what are mesenteries
fold of membrane that holds primitive gut in position
-derived from mesoderm
-in both peritoneal layers
peritoneum (single layer) surrounding organ is called
visceral peritoneum - at wall of organ
peritoneum (single layer) surrounding body is called
parietal peritoneum - at wall of body
mesentery (dual layer) - back is called
dorsal mesentery - attaches abdominal organs to the posterior abdominal wall
mesentery (dual layer) - front is called
-this layer …. during development except for region developing from foregut
ventral mesentery
degenerates
roles of mesentery
-holds abdominal organs in place
-pathway for blood vessels, lymphatics, innervation to reach abdominal organs
gut rotation is in specific order caused by …
differences in growth rate of the dorsal mesentery
structures move from midline to lateral, and innervation
explains why abdominal pain = midline
abdomen and pelvis - no clear ….
separation
kidney is retroperitoneal - what does this mean
sits behind the peritoneum
organ rotation leads to lesser/greater sacs -
-lesser sac - behind the stomach
-greater sac - at the front, rest of peritoneal cavity
inner layer of the alimentary canal secretes mucus is called -
mucosal
middle layer of the alimentary canal moves lumen contents is called -
muscular
outer layer of the alimentary canal secretes lubricating fluid is called -
serous
most dilated part of alimentary canal
stomach
stomach bordered between
oesophagus and small intestine
stomach has 2 openings -
2 curvatures and 2 surfaces
small intestine is where
digestion and absorption take place
-convoluted tubule
what is the name of the artery that provides blood to mid gut
superior mesenteric artery
what is the name of the artery that provides blood to hindgut
inferior mesenteric artery
lymphatics are named according to
which vessel they come from
superior mesenteric nodes from the -
midgut
inferior mesenteric nodes from the -
hindgut
at the end of the 4 weeks post folding both the … and … ends remain closed by membranes
cranial and caudal
examples of dorsal mesentery (attaches abdominal organs to back abdominal wall)
-greater omentum
-mesentery of small and large intestine
ventral mesentery is only retained in the …. region
foregut
example - lesser omentum links lesser curvature of stomach to back of liver, falciform ligament
lesser/greater sac communicate via
epiploic foramen
primitive gut formed as a result of the developing embryo undertaking 2 folds -
1 in the cranial-caudal axis
1 in the lateral plane
end of 4 weeks, both cranial and caudal ends are closed by membranes
role of stomach (2)
mechanical - muscle
chemical - digestion
lesser curvature of stomach on … border
superior
greater curvature of stomach on … border
inferior
wall of stomach composed of 3 layered muscle (3)
longitudinal, circular, oblique
small intestine divided into 3 main categories
duodenum
jejunum
ileum
DIGESTION AND ABSORPTION
which part of small intestine lies in the retroperitoneal space
duodenum
jejunum role
large surface area for absorption, increased by microvilli and circular folds
-so is very mobile - attached only to 1 edge
large intestine has 4 parts
ascending, transverse, descending, sigmoid
parts of large intestine that are retroperitoneal
ascending and descending
role of large intestine
reabsorb water, form faeces and expel
action of defacation in large intestine is controlled by
rectum/anus
which part of the gut features microvilli on its luminal surface
ileum
facts about GI tract
The epithelium of the mucosa varies in different parts of the GI tract
c.
The muscularis mucosa has different thicknesses in different regions
d.
Glands are only found in the submucosa of the duodenum and oesophagus
e.
Water recovery is a major role of the colon
in which region is both new activation for digestion and absorption of digestion products started
duodenum
