Development of the Gut Flashcards
What happens to the dorsal part of yolk sac during 3rd week of development? Name of communication between internalized yolk tube and yolk sac =
Dordsal part of yolk sac (which is in endoderm…remember that ectoderm has amniotic fluid) starts to be internalized and is surrounded by the coelom. The yolk sac surrounded by coelom subsequently becomes gut tube. Communication between cut tube and yolk sac = Vitelline (yolk) Duct
What is the goal of lateral gut tube? What make sup epithelial cells and guts? What is significant about the epithelial cells of the gut tube? What happens if this does not work properly?
Cuts off and isolated gut tube from yolk sac, upon fusing, forming ventral body wall. Epithelial: mesoderm. Gut internals: endoderm. Epithelial cells of the gut tube create epithelial plug, which plugs up gut tube. As development continues, the plug apoptosis (normally) and creates the gut tube again. If this does not occur completely, you get stenosis of the gut tube. If there is zero apoptosis (major L…), you have atresia of gut tube (plug is still present), and baby vomits upon eating because the food never makes it to the stomach. Same in gut tube stenosis.
What happens if there is a defect of the right and left lateral body fold fusion?
You get a weakness of the body wall, which is more likely to rupture, giving you an opening in the ventral body wall (Gastroschisis aka split belly). Result: abdominal content escapes through the body wall to the outside of the baby. Note that this is NOT a gi tract defect. The gi tract ends up floating in amniotic fluid. Also note that this defect often occurs tot he right of the midline/umbilical cord.
How long is the gut tube? What is the respiratory diverticulum, and when does it form? What is rostral to it?
Runs from mouth to anus…length of embryo and lines by endoderm. Respiratory diverticulum (4th week) becomes lungs and respirtatory system. Rostral to it = pharynx (5th week).
What happens if Vitelline duct does not close? What if it only partially fuse, leaving a tube lingering in abdomen from the small intestine? Where does Vitelline Tube extend from? What happens if it inflames? What makes Fibrous Cord variant of Ileal diverticulum (upon not degenerating) dangerous?
You get an opening between the outside world and the small intestine (Vitelline Fistula) if it does not degenerate before birth. Fecal material would then emerge from the umbilicus. If it only partially degenerates, you get Ileal (Meckel’s) Diverticulum. Note that Vitelline duct extends from Ilium. Inflammation of the persistent ileal diverticulum could create stomach pain, like that of appendicitis. Fibrous cord creates axis for intestine to rotate around, which could lead to intestinal occlusion.
What are the 3 branches that branch from the abdominal aorta (from most superior to most inferior)
They are celiac trunk, superior mesenteric, and inferior mesenteric arteries.
What receives blood from the celiac trunk? What are its organs?
Para Innervation:
Sympa Innervation:
Referred Pain:
Foregut: Esophagus, stomach, duodenum.
Para Innervation: Vagus
Sympa Innervation: Preganglionics (thoracic splanchnic nerves t5-t9). Postganglionics (celic ganglion)
Referred Pain: Epigastrium
What receives blood from the superior mesenteric artery? What are its organs?
Para Innervation:
Sympa Innervation:
Referred Pain:
Midgut: Remainder of duodenum, jejunum, ileum, cecum, appendix, ascending colon, transverse colon .
Para Innervation: Vagus
Sympa Innervation: Preganglionics (thoracic splanchnic nerves t9-t12). Postganglionics (superior mesenteric ganglion)
Referred Pain: Umbilical
What receives blood from the inferior mesenteric artery? What are its organs?
Para Innervation:
Sympa Innervation:
Referred Pain:
Hindgut: Remainder of transverse colon, descending colon, sigmoid colon, rectum, anal canal
Para Innervation: Pelvic splanchnic nerves
Sympa Innervation: Preganglionics (Lumbar splanchnic nerves L1-L2). Postganglionics (Inferior mesenteric ganglion)
Referred Pain: Hypogastrium
Is dorsal on top or bottom by embryologist convention?
Ventral on top
What are the associated adult names to the following fetal structures:
Coelom:
Peritoneum walls:
Ectoderm:
Endoderm:
How many organs are in peritoneal cavity?
Coelom: Peritoneal cavity Peritoneum walls: Mesoderm walls Ectoderm: Body wall Endoderm: Gut tube Zero organs in peritoneal cavity. There is never an organ in any given cavity. You can only have organs in the gut tube or the between the body wall and external peritoneum.
List the 3 rules of nomenclature
- Organs COMPLETELY surrounded by periteneum (gut tube) are called peritoneal organs. Organs PARTIALLY covered by periteneum, but note fully surrounded (kindeys, aorta) = retroperitoneal organ.
- When you have a peritoneal organ, the peritoneum surrounding it = visceral peritoneum. For retroperitoneal organs, the layer surrounding it = parietal peritoneum
- The peritoneum that connects visceral peritoneum to parietal peritoneum = Mesentery (Dorsal and ventral)
What is the goal of the dorsal and ventral mesentery layer?
Allows for blood supply (and all other vessels and nerves) to reach periteneal organ without entering the peritoneal cavity (remember, nothing enters the cavity). All peritoneal organs have a mesentery, through which they receive their blood supply, among other needs.
Where did the hepatic diverticulum come from? What develops from it? What happens when the organs reach their migratory destination?
Comes from VENTRAL mesentary out of the gut tube. Distal parts develop into liver components/liver and gallbladder. Proximal part turn into bile duct. Upon migration termination, ventral mesentray changes name to being a parietal organ surrounded by p visceral peritoneum
Name ligament between liver and body wall. Name part between liver and gut tube. Where does the bile duct live?
- Falciform ligament
2. Lesser omentum (here bile duct lives)
