alimentary canal pt.2 Flashcards
mesentery
a double layer of peritoneum that extends form the body wall to digestive organs
-holds organs in place
-provides a route for circ vessel and nerves
length determines motility
two examples of mesentery
-lesser omentum: runs form liver to stomach-posterior
-greater omentum: links the inferior surface of the stomach to adjacent organs.
seconadarily retroperitoneal :
organs fuse to the wall and lose their mesentery
intraperitoneal
digestive organs remain surrounded by the peritoneal cavity
structures made by peritoneum
- mesentery
- omentum: double layered mesentery attached to the stomach and first part of duodenum to adjacent organs
- ligament: two layers of peritoneum that connect two organs to eachother or organ to ab wall
development:
week 4 embryo has a inner tube composed of
endoderm: gives rise to the epithelium of alimentary canal and gut derived organs
splanchnic mesoderm: outer layers in the wall of alimentary canal
divisions of the primitive gut:
- foregut: esophagus, stomach, pancreas, duodenum, liver, bile duct
- midgut: small intestine distal to the bile duct, cecum, appendix, ascending and post of transverse colon
- hindgut: remainder of colon and rectum
the midgut grows _____ and is supplied by the _________ artery
rapidly
superior mesenteric artery
dev
as the midgut is growing it
herniates into the proximal part of the umbilical cord
dev:
return of midgut
rotates 270 around the axis of SMA
-avoids knots
blood supply
origin
abdominal aorta
blood supply
branches from abdominal aorta-unpaired
- celiac trunk: supplies foregut
- superior mesenteric artery: supplies midgut
- inferior mesenteric artery: supplies hindgut
gastric blood supply: stomach
heavily vascularized
-origin: celiac trunk
gastric blood supply: stomach
lesser curvature
-lesser curvature: recives blood from right and left gastric arteries
gastric blood supply: stomach
greater curvature
receives blood from the right and left gastro-omental arteries
3 main arteries of celiac trunk
left gastric artery: stomach
splenic artery: spleen
common hepatic artery: liver
venous drainage
main channel:
formed:
function
hepatic portal vein
formed by the union of the superior mesenteric and splenic veins
function: collects blood from alimentary tract, pancreas, spleen, and gallbladder
-carries to the liver
the foregut is drained
by the splenic vein
midgut is drained
by the superior mesenteric vein
hindgut is drained
inferior mesenteric vein
pathway of veins
inferior-splenic-joins with superior-hepatic-to liver for filtration
anastomeses
between caval and portal system all around the body
-not always filtered through the liver right away
blood supply of the oral cavity
supplied by external carotid artery
blood supply of the esophagus
supplied by branches of the abdominal aorta: brachial ,esophageal and phrenic
innervation of alimentary canal is from
enteric nervous system
sympathetic: thoraco-lumbar outflow
depresses
parasympathetic: cranio-sacral outflow
enourages
features of enteric nervous system
-continuation of ANS
independent of CNS
enteric neurons:
form relfex arcs of sensory , interneuron and motor neurons that control the muscular and secretory functions of digestive organs
enteric neurons
-mesenteric plexus
located in the smooth muscle, controls peristalsis
enteric neurons
submucosal plexus
located in the submucosal layer, controls secretion and the muscularis mucosae.
histal hernia
protrusion of part of stomach into mediastinum through esophageal hiatus
gastric ulcers
open lesions of the mucosa of the stomach
omphalocele
congenital umbilical hernia of the midgut
