Lecture 29: Abdomen II Guit Development Of Peritoneum Flashcards
foregut will form what structures (6)
stomach
liver
gallbladder
spleen
pancreas
1/5 duodenum
midgut will form (6)
4/5 duodenum
jejunum
ileum
cecum
ascending colon
2/3 transverse colon
midgut will form (6)
4/5 duodenum
jejunum
ileum
cecum
ascending colon
2/3 transverse colon
hindgut will form (4)
1/3 transverse colon
descending colon
sigmoid colon
rectum
intraembryonic coelem: 4 cavities
-1 pericardial cavity
-2 pericardioperitoneal canals
-1 peritoneal cavity
peritoneum definition
single serous layer of flattened mesothelial cells supported by fibroelastic connective tissue that attaches to body wall, diaphragm and viscera
peritoneum develops from
intraembryonic coelom
parietal peritoneum derived from
parietal layer of lateral plate mesoderm (next to body wall)
visceral peritoneum derived from
visceral layer of lateral plate mesoderm (next to organs)
what structures are derived from the intraembryonic coelom (3)
-peritoneum
-visceral and parietal pericardium
-pleura
peritoneal cavity definition
space enclosed by peritoneum
peritoneal fluid secreted by what cells
-secreted by mesothelial cells into peritoneal cavity
function/role of serous fluid in GI motility
-allows layers of peritoneum to glide against one another
-prevent viscera from attaching to abdominal wall
unique feature of peritoneum (hint: clinical relevance)
-large, rapidly absorptive surface area
-toxins are readily absorbed, good environment for bacterial growth = peritonitis
how does herniation of midgut during development lead to adult intestinal topography
- The size of the developing midgut is too large to be contained within the embryonic abdomen so it is forced to herniate into umbilical cord = makes for weak ventral abdominal wall in newborns and young animals
-Herniates into peritoneal cavity ventrally, takes two layer of peritoneum = mesentery, completes a 270 degree rotation so large intestine becomes looped around small intestine
-During this herniation the intestine drags vasculature, nerve supply, and lymphatics
mesentery: developmental definition
2 layers of peritoneum that migrate together as the developing midgut migrates ventrally
mesentery: definition
double layer of peritoneum that forms from invagination of peritoneum
what structure suspends the midgut from the dorsal abdominal wall
dorsal mesentery
root of the mesentery
peritoneal attachment between dorsal/great mesentery and dorsal abdominal wall
what structures are suspended/supported by dorsal mesentery
-duodenum
-jejunum
-ileum
intraperitoneal organs: definition
organs suspended from dorsal abdominal wall within peritoneal reflections
retroperitoneal organs: definition
-organs directly joined to abdominal wall
-no mesentery or peritoneum dorsally
3 retroperitoneal organs
kidneys
aorta
pancreas
volvulus
loop of intestine and mesentery that becomes twisted
can lead to strangulated and obstructed bowel
greater omentum functions
-prevent adhesions between abdominal viscera/organs and ventral abdominal wall
-prevent spread of infection from perforations of intestines (seals off site of perforation)
greater omentum definition
extended fold of dorsal mesogastrium
-attaches greater curvature of stomach to dorsal body wall at pancreas
-covers abdominal cavity
lesser omentum definition
-spand distance from lesser curvature of stomach to porta of liver
lesser omentum contains (3)
-portal vein
-hepatic artery
-bile duct
foregut: blood supply, sympathetics, parasympathetics
-celiac trunk/artery
-sympathetics: celiac ganglion
-parasympathetics: vagus (CN X)
midgut: blood supply, sympathetics, parasympathetics
-cranial mesenteric artery
-sympathetics: cranial mesenteric ganglion
-parasympathetics: vagus
hindgut: blood supply, sympathetics, parasympathetics
-caudal mesenteric artery
-sympathetics: caudal mesenteric ganglion
-parasympathetics: pelvic splanchnic nerves
4 layers of gut/GI
-mucosa
-submucosa
-muscularis externa
-adventitia (rough) or serosa (smooth)
3 layers of mucosa
-epithelium
-lamina propria
-muscularis mucosa
lamina propria
CT layer with immune cells
muscularis mucosa function and definition
contract mucosa
multiple smooth muscle layers
muscularis externa: 2 sublayers of muscle
inner circular
outer longitudinal
muscularis externa function
move luminal conent
inner circular layer function
acts as series of sphincters to restrict luminal flow
where is adventitia found (2 organs)
-esophagus
-rectum, anal canal
does esophagus have a lamina propria
no
mucosa epithelium in stomach, small intestine and large intestine
simple columnar
mucosa epithelium in esophagus
stratified squamous
mucosa epithelium in rectum
stratified sqamous
submucosa in stomach called
rugae
small intestine submucosa
all circular folds
brunners glands in duodenum
what muscle layer is absent in large intestine
submucosa
lamina propria in stomach
fundic, cardiac and pyloric glands
