Quiz 4 - Abdominal Embryology Flashcards
during lateral and longitudinal folding, the endoderm is incorporated into the embryo as the _____
gut tube
the gut tube will form…
epithelial lining of the gut and its associated organs
once the gut tube is incorporated into the body of the embryo, it can be subdivided into 3 regions…
- foregut: cranial blind-ended portion that is capped by oropharyngeal membrane
- midgut: portion that remains temporarily connected to the yolk sac thru the vitelline duct
- hindgut: caudal blind-ended portion that is capped by the cloacal membrane.
allantois
-a small diverticulum of the hindgut that extends into the connecting stalk
gut tube is surrounded by the ________
visceral layer of lateral plate mesoderm, which will form the smooth muscle, connective tissue, and visceral peritoneum of the gut and its associated organs
as the gut tube is being incorporated into the body of the embryo, it moves away from the ____ body wall and becomes “suspended” into the intraembryonic coelem
dorsal
initially, the gut tube is suspended from the dorsal body wall by a ______
mesentary; a mesentary is a double layer of visceral peritoneum that connects an organ to the body wall. Vessels and nerves travel to the gut tube between these layers of visceral peritoneum.
dorsal mesentary
- remains in the regions of the abdominal portion of the foregut, midgut, and hindgut
- regions of the dorsal mesentary are named according to the organs they connect to the posterior body wall
ventral mesentary
-develops in the region of the abdominal portion of the foregut as a caudal downgrowth from the septum transversum
what does the ventral mesentery form?
- falciform ligament (formed by the division of the ventral mesentery by the growing liver)
- lesser omentum
organs that are suspended in the abdominal cavity by a mesentery are referred to clinically as _____
intraperitoneal
organs that lie against the posterior body wall and are covered by peritoneum only on their anterior surface are considered _____
retroperitoneal
primarily retroperitoneal
-an organ that is never suspended by a mesentery
secondarily retroperitoneal
- an organ that is initially suspended by a mesentery, but is pushed against the body wall during development
- visceral and parietal layers of the peritoneum meet, fuse, and be reabsorbed
- the organs are now only covered by peritoneum on their anterior surface
which structures/organs are primarily retroperitoneal?
-aorta
-iliac arteries
-IVC
adrenal glands
-kidneys
-ureter
-rectum (technically SUBperitoneal)
which structures/organs are secondarily retroperitoneal?
- duodenum
- pancreas
- ascending colon
- descending colon
which structures/organs are intraperitoneal?
- liver & gallbladder
- distal esophagus
- stomach
- proximal duodenum
- small intestine
- cecum
- transverse colon
- sigmoid colon
- spleen
general features of gut development
- MOST organs develop as outgrowths of the gut tube
- gut tube rotations force some organs to change orientation
- each region of the gut tube is associated with particular vessels and nerves
blood supply of gut tube
3 major branches (celiac trunk, superior mesenteric artery, inferior mesenteric artery) of the abdominal aorta supply the gut tube. In general, an organ derived from a particular region of the gut tube will be supplied by the artery that was associated with it in the embryo.
celiac trunk supplies ___
embryonic foregut
superior mesenteric artery (SMA) supplies ___
embryonic midgut
inferior mesenteric artery (IMA) supplies ___
embryonic hindgut
which nerve supplies embryonic foregut?
Sympathetic: greater splanchnic nerve (T5-T9) via celiac ganglion
Parasympathetic: vagus nerve (CN X)
which nerve supplies embryonic midgut?
Sympathetic: lesser and least splanchnic nerves (T10-T12) via superior mesenteric ganglion
Parasympathetic: vagus nerve (CN X)
which nerve supplies embryonic hindgut?
Sympathetic: lumbar splanchnic nerves (L1-L2) via inferior mesenteric ganglion
Parasympathetic: pelvic splanchnic nerves (S2-S4)
derivatives of the foregut
- pharynx and derivatives
- trachea, bronchi, lungs (lower resp system)
- esophagus
- stomach
- proximal 1/3 of duodenum
- liver & gallbladder
- pancreas