GI development 1 Flashcards
Name the 3 parts of the primitive gut tube:
1) Foregut
2) Midgut
3) Hindgut
What name is given to the future mouth of the primitive gut tube?
Stomatodeum
What is the Stomatodeum?
Future mouth of the primitive gut tube
What name is given to the future anus of the primitive gut tube?
Proctodeum
What is the Proctodeum?
Future anus of the primitive gut tube
Which germ layer gives rise to the internal lining of the GI tract?
Endoderm
Which germ layer gives rise to the external lining of the GI tract? (Musculature and peritoneum etc)
Splanchnic mesoderm
What is the function of the Vitelline duct?
Connects the yolk sac to the hindgut
What name is given to the duct which connects the yolk sac and hindgut?
Vitelline tract
What is the name of the vestigial remnant of the vitelline duct, present in 2% of the population?
Meckel’s Diverticulum
List the (GI) adult derivatives of the foregut:
- Oesophagus
- Stomach
- Liver
- Gall bladder
- Pancreas
- Proximal 1/4 of duodenum
What is the blood supply of the adult derivatives of the foregut?
Coeliac trunk
At which vertebral level does the Coeliac trunk branch from the abdominal aorta?
T12
Name the 3 main branches of the Coeliac trunk:
1) Splenic artery
2) Common hepatic artery
3) Left gastric artery
List the (GI) adult derivatives of the midgut:
- Distal 3/4 of duodenum
- Jejunum
- Ileum
- Caecum (+ appendix)
- Asc. colon
- Proximal 2/3rds Transverse colon
Which 2 structures form from the junction between the foregut and midgut? What implications does this have on their blood supplies?
1) Pancreas
2) Duodenum
Mixed blood supplies (Coeliac trunk + SMA)
What is the blood supply of the adult derivatives of the midgut?
Superior Mesenteric Artery (SMA)
At what vertebral level does the SMA branch from the abdominal Aorta?
L1
List the (GI) adult derivatives of the hindgut:
- Distal 1/3rd Transverse colon
- Desc. colon
- Sigmoid colon
- Rectum
- Upper anal canal
What is the blood supply of the adult derivatives of the hindgut?
Inferior Mesenteric Artery (IMA)
At what vertebral level does the IMA branch from the abdominal Aorta?
L3
What are the main 3 branches of the IMA?
1) Left colic artery
2) Sigmoid artery
3) Superior Rectal artery
What are the 3 main branches of the SMA?
1) Ileocolic artery
2) Right colic artery
3) Middle colic
What structure divides the intraembryonic coelom into the thoracic and abdominal cavities?
Diaphragm
Define mesentery:
Double layer of peritoneum
- suspending gut tube from abdominal wall
- allows conduit for blood + nerve supply
- allows motility (when needed)
- formed from condensation of splanchnic mesoderm
Which type of mesentery suspends the fore-, mid- and hindgut from the abdominal walls?
Foregut = Ventral + Dorsal mesenteries Midgut = Dorsal only Hindgut = Dorsal only
Which structures divide the peritoneal sac into left and right sacs? (the future greater and lesser sac’s)
Ventral and Dorsal mesenteries
Which mesentery forms the greater omentum?
Dorsal mesentery
Which mesentery forms the lesser omentum?
Ventral mesentery
Define omentum:
Fold of peritoneum which surrounds abdominal organs
The ventral and dorsal mesenteries divide the peritoneal sac into left and right sac’s. Which sac becomes the lesser sac?
Right sac –> Lesser sac
What is the importance of the longitudinal rotation of the stomach?
- Lesser curvature now lies on RHS
- Greater curvature now lies on LHS
- Movement of mesenteries creates space behind stomach = Lesser sac
What is the importance of antero-posterior rotation of the stomach?
- Cardia and pylorus move horizontally
- Greater curvature moves inferiorly
What is the difference between primary and secondary retroperitoneal organs?
Primary = never had a mesentery (never in peritoneal cavity) Secondary = Had mesentery which fused with posterior abdominal wall, immobilising organ
List the primary retroperitoneal organs:
- Kidneys
- Bladder
- Ureters
- Rectum
- Uterus
(+ Aorta/IVC)
List the secondary retroperitoneal organs:
- Duodenum
- Pancreas
- Asc + Desc colon
What is the name given to the part of the peritoneum which covers secondary retroperitoneal organs?
Fusion fascia
Which organs of the lower GI tract remain suspended from the posterior abdominal wall (do not become retroperitoneal)?
Jejunum
Ileum