Embryology of GI Tract Flashcards
(67 cards)
1
Q
what weeks are the embryonic period
A
- weeks 3-8
2
Q
what happens in the fetal period
A
- growth and maturation
3
Q
what is the result of injury during the embryonic period
A
- major congenital anomalies
4
Q
when are the three germ layers formed?
A
- week 3
5
Q
we begin week 4 as what kind of embryo
A
- flat embryo
6
Q
what does longitudinal folding do
A
- moves the heart in the new thorax
7
Q
what does transverse folding do
A
- creates a 3D trunk
8
Q
transverse folding creates the GI tract from what
A
- yolk sac
9
Q
GI tract lies where
A
- peritoneal cavity
10
Q
GI tract suspended by
A
- mensentaries
11
Q
what happens with the dorsal mesentary
A
- remains
- suspends GI tract
12
Q
what does the dorsal mesentery contain
A
- vasculature
13
Q
what happens with the ventral mesentary
A
- disappears except in upper abdomen (liver)
14
Q
what is a mesentery
A
- connective tissue that suspends GI tract in peritoneal cavity and attaches to abdominal wall
15
Q
what does the mesentery carry
A
- blood and nerve supply to suspended organs
16
Q
what germ layer creates the liver, pancreas, and epithelium of the GI tract
A
- endoderm
17
Q
what germ layer creates the connective tissue and muscle of viscera
A
- lateral endoderm
18
Q
what does the foregut become
A
- pharynx
- esophagus
- stomach
- part of duodenum
- pancreas
- liver
19
Q
what does the midgut become
A
- duodenum
- jejunum
- ileum
- cecum
- ascending colon
- 2/3 of transverse colon
20
Q
what does the hindgut become
A
- rest of transverse colon
- descending colon
- sigmoid colon
- rectum
- cranial anal canal
21
Q
what vascularizes the foregut
except
A
- celiac trunk
- NOT PHARYNX
22
Q
what vascularizes the midgut
A
- superior mesenteric artery
23
Q
what vascularizes the hindgut
A
- inferior mesenteric artery
24
Q
the entire GI tract begins as a
A
- tube
25
how does the midgut form
- extends out (herniates) as a loop into the umbilical cord
26
what happens to the cranial limb of the midgut
- grows long and forms folds
27
what does the cranial limb of the midgut become
- small intestines
28
what happens to the caudal limb of the midgut
- doesn't grow long
29
what does the caudal limb of the midgut become
- proximal large intestines
30
when do the cranial and caudal limb of the midgut retune to the abdominal cavity
which goes first
then what happens
- week 10
- cranial before caudal
- they rotate into final positions
31
development of the tract - specifically the tube
- originally patent (open lumen)
- fills in (closed lumen)
- recanalizes (open lumen)
32
in patients with which condition do we also see duodenal atresia
- down syndrome
33
pathogenesis of duodenal atresia
- failure of recanalization
34
clinical symptoms of duodenal atresia
- bilious vomiting
35
x ray of duodenal atresia
- double bubble
36
what is atresia
- absence of or narrowing of opening or passage in the body
37
congenital pyloric stenosis - common or uncommon
- common in males
38
pathogenesis of congenital pyloric stenosis
- pyloric wall hypertrophy
39
clinical symptoms of congenital pyloric stenosis
- palpable mass
| - projective non-bilious vomiting
40
pathogenesis of umbilical hernia
- after intestines return to abdomen in week 10, they reherniate through imperfectly closed umbilicus
41
what does a umbilical hernia look like
- midline protrusion containing small quality of abdominal contents
- covered by skin
42
omphalocele pathogenesis
- persistence of herniated intestines that do not return to abdomen in week 10
43
what does omphalocele look like
- midline protrusion at navel containing intestines
| - covered by peritoneum-like transparent sac
44
gastroschisis pathogenesis
- abdominal walls fails to close after intestines return to abdomen
45
what does gastroschisis look like
- protrusion of GI tract near but not in midline
| - not covered by skin or peritoneum
46
meckel's diverticulum epidemiology
- most common congenital anomaly of GI tract
47
pathogenesis of meckel's diverticulum
- remnant of vitelline duct
48
what is the vitelline duct
- temporary structure that joins yolk sac to developing midgut
49
anatomy of meckel's diverticulum
- distal small intestine
- 2 ft from ileocecal junction
- 2 inches long
50
histopathogloy of meckel's diverticulum
- may have gastric epithelium or pancreatic tissue lining
51
clinical symptoms of meckel's diverticulum
- bleeding, intussusception, volvulus, obstruction in first 2 years of life
52
Hirschsprung's disease etiology
- absence of innervation in wall of distal GI
53
pathogenesis of Hirschsprung's disease
- normal migration of neural crest cells that would become ANS neurons does not occur into distal colon or rectum
54
what do we see in the aganglionic area in Hirschsprung's disease
- constricted
55
what do we see in the proximal area in Hirschsprung's disease
- dilated
| - can become congenital megacolon
56
clinical symptoms of Hirschsprung's disease
- failure to pass meconium
| - constipation
57
liver develops from
- ventral mesentary
58
ventral mesentery composed of
- falciform ligament
| - hepatogastric ligament
59
where is the falciform ligament relative to the liver
- anterior to liver
60
where is the hepatogastric ligament relative to the liver
- posterior to liver
61
what happens to the liver as it enlarges during development
causes
- rotates into right abdominal area
| - rotation of stomach and spleen into final orientations and locations
62
what does the pancreas arise from
- ventral and dorsal pancreatic bud of mesentary
63
ventral bud of pancreas arises from same invagination as
- liver
| - bile duct/gallbladder
64
which bud of the pancreas fuses with which
where
- ventral rotates and fuses with dorsal
| - on left side of GI tract
65
what does the ventral bud of the pancreas become
- head of pancreas
- main pancreatic duct
- carries bile with it
66
what does the dorsal bud of the pancreas become
- head, body and tail of pancreas
67
as the liver and other organs develop and grow in the mesentery, what happens to the pancreas
- pushed until it lies along left posterior abdominal wall
| - fuses in place and becomes retroperitoneal
