Embryo 1 Flashcards
Endoderm
-epithelial lining and glands of GI tract
During ____ _____, endoderm from the _____ portion of the _____ ____ is incorporated into the embryo= forms the innermost lining of the gut tube.
body folding
dorsal portion
yolk sac
Gut Tube
-epithelial lining and glands of GI tract
Splanchnic Mesoderm
- smooth m and connective tissue of GI tract
- -includes mesenteries
Peritoneum
-serous membrane lining the abdominal cavity (parietal) and organs (visceral)
Mesentery
-double layer of peritoneum that suspends an organ from the body wall (can contain CT, blood vessels, lymphatics, nn)
Mesogastrium
-lesser omentum= hepatogastric (liver to stomach) and hepatoduodenal (liver to duodenum) ligaments
Ectoderm contribution of GI Tract
-neural crest
Neural crest cells migrate into walls of the GI tract to form the ___ ___ ___.
- enteric nervous system
- -neuroectoderm
-
-
foregut
midgut
hindgut
Arterial Supply to Pharynx
pharyngeal arch aa
Arterial Supply to Foregut
celiac trunk a
Arterial Supply to Midgut
superior mesenteric a (SMA)
Arterial Supply to Hindgut
inferior mesenteric a (IMA)
Foregut Derivatives:
- P___
- L___
- E___
- S___
- D___
- A___
pharynx lower respiratory system esophagus stomach duodenum (prox 1/2) associated organs (liver, gall bladder, biliary system, pancreas)
______ develops as the portion of the _____ immediately caudal to the pharynx.
Esophagus
Foregut
WEEK ___:
-_______ _______ appears on ventral side of foregut –will become the trachea, respiratory tree, and lungs)
4
respiratory diverticulum
_______ ______ grows in from the lateral sides of the foregut, dividing the foregut into the lower respiratory tract (ventrally) and esophagus (dorsally)
Tracheoesophageal Septum
WK 5= trachea splits to form lungs
______: the abnormal narrowing of lumen/orifice (tubular organ or structure)
Stenosis
_____: the condition in which a body lumen or orifice is abnormally closed or absent
Atresia
____: an abnormal passageway btw two organs/vessels or btw an organ and the external environment
Fistula
Risk of Polyhydramnios:
esophageal atresia
tracheoesophageal fistula
–too much amniotic fluid in amniotic cavity= needs to be swallowed for proper gut development
WEEK ___:
- a portion of foregut caudal to esophagus begins to dilate uniformly
- as stomach enlarges, its ____ side expands faster than the other sides and will become the ____ ____
- _____ face of stomach will become the ____ ____
4 dorsal greater curvature ventral lesser curvatures
Stomach undergoes ___ ____ ____ (if looking from superior view)
90 degree clockwise rotation= quarter turn to right
Ventral side (lesser curvature) ends up on the ____
right
Dorsal side ends up on the ____
left
Right _____ n. now supplies _____ stomach.
vagus n
dorsal
Left ____ n. now supplies _____ stomach.
vagus n
ventral
_____ _____ _____: _____ of mainly the circular layer of smooth m narrows the _____ lumen, preventing the passage of stomach contents
=distended stomach
=projectile vomitint
Hypertrophic Pyloric Sternosis
- hypertrophy
- pyloric
As stomach rotates, the ____ _____ is carried to the left.
This enlarges the _____ ____ (lesser sac of peritoneum) into a sizable recess btw the stomach and posterior abdominal wall.
dorsal mesogastrium
omental bursa
Omental Bursa ( \_\_ months) -\_\_\_\_\_\_ carried to the left with \_\_\_\_ \_\_\_\_\_
2 months
- spleen
- dorsal mesogastrium
–recess to allow for fluid movement of stomach
_______ forms as a C shaped loop distal to the stomach
Duodenum
______: proximal 1/2 is in _____ and is supplied by the ____ _____
Duodenum
foregut
celiac trunk
______: distal 1/2 is in ______ and is supplied by the ___
Duodenum
midgut
SMA
______ _____ _____: foregut-midgut split just to pening for pancreatic and common bile ducts
major duodenal papilla
Duodenum and Pancreas become _______
retroperitoneal
As stomach rotates, duodenum twists w/ it in a CW direction.
The _____ duodenum and pancreas become pressed against ____ ____ ____ (secondarily retroperitoneal).
Their dorsal _____ fuse w/ parietal _____ and are lost.
distal
posterior abdominal wall
mesenteries
peritoneum
Duodenal Stenosis and Atresia:
Failure of lumen to recanalize by end of week ___.
Vomitus contains bile (green stained) if obstruction is distal to _____ ____ _____.
8
major duodenal papilla
______ ______ emerges ventrally from endoderm of distal foregut (wk __), grows superiorly toward septum transversum and gives rise to ____, ___ ___, and ____ ____.
Hepatic diverticulum 4 liver gall bladder bile ducts
The liver, gall bladder, biliary tree, and pancreas all develop as ______ _______ from the _____ _____.
endodermal diverticula
distal foregut
Pancreas emerges from the ____ ____ as 2 _______ buds: ____ bud and ___ bud
distal foregut
endodermal
dorsal
ventral
As ______ rotates, _____ bud swings w/ it in CW direction until aligning and fusing w/ _____ bud.
duodenum
ventral
dorsal
Ventral bud becomes ____ ____ + ____ ___ __ ____ of pancreas.
uncinate process
inferior portion of head
___ ____ ___= distal portion of dorsal bud duct + ventral bud duct
main pancreatic duct
____ _____ ____ = proximal dorsal bud duct
accessory pancreatic duct
______ _____: ventral bud develops in 2 portions that usually fuse prior to rotation.
If they fail to fuse, each portion may wrap oppositely around the duodenum and fuse w/ the other. forming an obstructive ring.
Annular Pancreas
Midgut Derivatives: Cranial Limb- -D\_\_\_ -J\_\_\_ -I\_\_\_
Caudal Limb
- I___
- C/A___
- A___
- T___
distal 1/2 duodenum (just after major duodenal papilla) jejunum ileum (proximal and distal) cecum and appendix ascending colon proximal 2/3 transverse colon
______ ____ is the connection btw midgut and yolk and sac
-temporary
vitelline duct
_____ ______ ______ (WK __-__):
-insufficient room in the abdominal cavity to temporary herniation of midgut loop into the proximal umbilical cord
Physiological Umbilical Herniation
WK 6-10
______ ______:
- persisting umbilical herniation
- viscera covered by amnion and WITHIN proximal umbilical cord
Congenital Omphalocoele
_______:
- hernia is through the body wall and does not involve umbilical cord
- exposure to amniotic fluid can damage viscera
Gastrochisis
1st Midgut Rotation: WK __:
___ degree _____ rotation (when viewed anteriorly)
-_____ is axis of rotation
6
90
CCW
SMA
2nd Midgut Rotation: WK __:
-as intestines return to abdomen
____ degree ____ rotation brings intestines to normal position
10
180
CCW
Midgut and Hindgut Assume Definitive Positions:
- ascending and descending colon become _____ _____
- their dorsal mesenteries are lost after fusing w/ the parietal peritoneum of the posterior abdominal wall
secondarily retroperitoneal
Intraperitoneal:
- D___
- J/I___
- T___
- S___
duodenum (proximal)
jejunum, ileum
transverse colon
sigmoid colon
Retroperitoneal:
- D___
- P___
- A___
- D___
- K___
duodenum (distal) pancreas ascending colon descending colon kidney (primary retroperitoneal)
Nonrotation:
-caudal limb returns first and occupies the left side of abdominal cavity, resulting in a ___-____ ____
left-sided colon
Normal 1st midgut:
-rotation of ___ degrees ___ w/in _____ ____
90
CCW
umbilical cord
Reversed 2nd midgut:
-rotation of ____ degrees ___ as _____ return
180
CW
intestines
Result of Reversed Rotation of Midgut:
- net rotation is _____ degrees ____
- midgut and hindgut in normal positions except ______ is central to TVC (doesn’t become retroperitoneal)
90
CW
duodenum
______: abnormal rotation may cause intestinal loop twist around mesenteric attachment site
-can result in bowl obstruction/compromised blood flow leading to stenosis/atresia/ischemia/necrosis
volvulus
Intestines become temporarily occluded by epithelial cells at wk ___
-should recanalize by the end of wk __
6
8
______ (______) ______:
-remnant of the _____ (omphaloenteric) duct persists as a finger like outpounching of the ileum
~~40-60 cm from ileocecal junction
-may contain pancreatic tissue/gastric mucosa that secretes acid, causing ulcers and bleeding
Meckel’s (Ileal) Diverticulum
vitelline
Hindgut Derivatives:
- T___
- D___
- S___
- R___
- A___
distal 1/3 transverse colon descending colon (derived from posterior portion of the cloaca after it is partitioned by the urorectal septum) sigmoid colon rectum superior portion of anal canal
_____ _____: grows inferiorly toward the cloacal membrane, dividing it into urogenital and anal membranes and partitioning the ___ into the ____ ____ (ventrally) and the ____ ____ (dorsally)
Urorectal Septum
cloaca
urogenital sinus
anorectal canal
Arterial Supply of Anal Canal from hindgut:
superior rectal a
Arterial Supply of Anal Canal from proctodeum:
inferior rectal a
______: can result if the urorectal septum fails to completely separate the hindgut from the urogenital sinus or if the cloaca is too small
Fistulas
\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_ (Aganglionic Megacolon): -affects variable portions of the bowel where \_\_\_\_ \_\_\_\_ cells fail to migrate to form the \_\_\_\_ NS
-anganglionic portion constricts, bowel distends proximal to constriction, can lead to severe constipation/failure to thrive
Hirschsprung’s Disease
neural crest
enteric
Gastrulation begins:
WK 3
Mesenteries:
- Ventral Mesogastrium:
- Dorsal Mesogastrium:
- Mesoduodenum
- Mesentery Proper:
- Mesocolon:
Ventral= lesser omentum; falciform lig Dorsal= great omentum Proper= small intestines Colon= large intestine
Dorsal Mesogastrium –> Greater Omentum=
starts from the greater curve of the stomach to the transverse colon
Retroperitoneal:
behind/outside the abdominal cavity
Primarily (kidneys) vs Secondary (pancreas and duodenum)
Total Turn of Stomach:
CCW 270 degrees
