Abdominal Cavity 1 Flashcards
What does the ectoderm form in the gut?
Anus (proctodeum) and mouth (stomodeum)
What does the mesoderm form in the gut
Splanchnic mesoderm: muscles, muscular walls, and most connective tissues including bones
What does endoderm form in gut?
Lining of gut and most gut derived organs
What is function of yolk sac?
Provides nourishment for baby before placenta is formed.
Also forms respiratory tract, genitourinary system and gastrointestinal tract.
What comprises the foregut?
Stomodeum to first 1/3 of duodenum.
Arterial Supply is celiac trunk
Also gives rise to pharyngeal pouches
Contents of the midgut?
Last 2/3 of duodnum to proximal 2/3 of colon.
Arterial supply is superior mesenteric artery
Gives rise to yolk stalk
Contents of the hindgut?
Last 1/3 of colon to proctodeum.
Arterial supply: inferior mesenteric artery
Gives rise to allantois
What is recanalization?
Hollowing of the primitive gut tube. Done at vacuoles. Errors cause atresia (blockage) or stenosis (narrowing)
The mesentaries are composed of what?
Double layer of peritoneum derived from splanchnic mesoderm. Have parietal and visceral components.
What does the ventral mesentary disintegrate into?
falciform ligament: from liver to ventral body wall
coronary ligament: liver to diaphragm.
lesser omentum from liver to stomach and duodenum. not attached to body wall.
An organ suspended in the mesentary is called _________
intraperitoneal (stomach, spleen, transverse colon)
An organ that has always been behind the peritoneum is called __________
Primarily retroperitoneal (esophagus, rectum, anal canal, kidneys)
An organ that has developed in mesentary and is now behind mesentary due to rotation and mesentaric fusing is called _____________
Secondarily retroperitoneal (distal 2/3 of duodenum, ascending and descending colon)
What mnemonic is good for knowing what is retroperitoneal?
Suprarenal glands
Aorta, vena cava
Duodenum (2nd and 3rd)
Pancreas Ureters Colon (asc and desc) Kidneys Esophagus Rectum
What comprises the foregut?
Pharynx, esophagus, stomach and proximal 1/3 of duodenum
What develops off the foregut?
Pharyngeal pouches, lower respiratory system, liver, pancreas, gallbladder
What creates the curvatures of the stomach?
the dorsal border grows faster than the ventral border (creates greater and lesser curvatures)
Describe stomach development
Rotates 90 degrees along longitudinal axis
Lesser curve moves right
Greater curve moves left
Vagus nerves twist with stomach, R ends up on dorsal surface, L on ventral surface.
What is spleen derived from?
NOT endoderm. Splanchnic Mesoderm of dorsal mesentary
How does the pancreas form?
Two buds: one ventral (small) and other dorsal, as it twists they get smacked together to form one pancreas
What forms the ducts for liver, pancreas and gallbladder?
Solid ventral outgrowths of the duodenum
What is an annular pancreas?
Pancreas strangling the gut tube due to improper rotation.
What does the midgut rotate around during development?
Superior mesenteric artery (also the primary artery of midgut)
What are the contents of the midgut?
Small intestine (besides 1st 1/3 of duodenum), cecum, appendix, ascending colon, proximal 2/3 of transverse colon.
Describe midgut rotation
Rotates counter-clockwise viewed from ventral side.
What errors can occur during midgut development?
Non rotation
Mixed rotation and volvulus (blockage due to intestine twisting around itself)
Reversed rotation
Internal hernia (mesentary enclosing intestines)
Midgut volvulus with duodenal obstruction
What develops from hindgut
urinary bladder and most of urethra
What are the contents of the hindgut?
distal 1/3 of transverse colon, descending colon, rectum, superior part of anal canal
What does the urorectal septum divide?
Allantois and yolk stalk. Separates cloaca into urogenital membrane and anal membrane.
What is the pectinate line and some significant features of it?
Separates anal canal into endoderm (above) and ectoderm (below). No pain receptors above the lie. Above the drainage and innervation is same as hindgut. Below is abdominal wall.
Rectourethral fistula clinical presentation
Peeing feces due to connection of rectum and urethra
Rectovaginal fistual clinical presentation
Feces coming out of vagina due to connection of rectum and vagina.
