Lecture 24: Embryology of the Digestive System and Foregut Flashcards Preview

Structures (ASV) > Lecture 24: Embryology of the Digestive System and Foregut > Flashcards

Flashcards in Lecture 24: Embryology of the Digestive System and Foregut Deck (70):
1

components of digestive tube

mouth, pharynx and esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (cecum, colon, rectum, anal canal, anus)

2

accessory organs to digestive process

teeth, salivary glands, liver, pancreas

3

when primordial gut begins to develop

beginning of week 4

4

beginning of digestive tract

orophorengeal membrane, made of ectoderm and endoderm

5

stomodeum

orophorengeal membrane other name

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fibroblast growth factors

establish anterior/posterior positioning of primordial gut

7

what signals for induction of endoderm

FGF-4 and activins

8

what does endoderm do in primordial gut formation

specifies temporal and positional information

9

derivatives of the foregut

primordial pharynx and derivatives (oral cavity, pharynx, tongue, tonsils, salivary glands, upper respiratory system)

lower respiratory system

esophagus and stomach

duodenum proximal to bile duct

liver, biliary appartus, pancreas

10

what separates esophagus?

T-E septum

11

makeup of esophagus

upper 1/3: striated muscles from pharyngeal arches

lower 1/3: smooth muscle from surrounding splanchnic mesenchyme

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nerve supply to esophagus

CN X

13

main blood supply to esophagus

celiac trunk

14

epithelium effect on developing esophagus

obliterates the lumen but it then recanalizes

15

T-E septum during esophagus development

separates T-E structures

16

esophageal stenosis

narrow esophagus

due to incomplete recanalization during 8th week or failure of esophageal blood vessels to develop

17

when does stomach develop

week 4

18

shape change of developing stomach

tubular structure dilates --> fusiform enlargement

19

direction fusiform enlargement of stomach develops

anterior to posterior

20

posterior part of developing stomach

greater curvature
grows faster, toward vertebral column

21

anterior part of developing stomach

lesser curvature, grows slower, toward anterior abdominal wall

22

rotation of develop stomach

weeks 4-6
90 degrees in a clockwise fashion

23

innervation of stomach wall

vagus nerve
L vagus: anterior
R vagus: posterior

24

dorsal mesogastrium

aka greater omentum

dorsal mesentery of stomach region, suspends stomach to posterior abdominal wall during rotation/development

25

dorsal mesogastrium creates

an omental bursa as it rotates to left during stomach rotation

26

ventral mesogastrium

suspends stomach and duodenum to liver and ventral abdominal wall

27

omental bursa

big hole formed by clefts in dorsal mesogastrium that coalesce

allows movement of stomach

28

greater omentum

layers of dorsal mesogastrium elongate and fuse, become greater omentum- fatty sheath lining abdominal cavity

29

what is enlarged in overweight people

omentum - becomes very fatty

30

congenital pyloric stenosis

extreme narrowing of pyloric lumen of pyloric canal- muscular valve- so food passage is obstructed

results in projectile vomiting

3/1000 births, more males than females

31

derivation of duodenum

begins week 4; continues into 5-6

dually derived from: foregut proximal to level of bile gut & mudgut

has dual blood supply

32

blood supply to duodenum

celiac artery
superior mesenteric artery

33

duodenum rotation

loop projects ventral, rotates to the right

34

duodenum recanalization

week 5-6, lumen becomes obliterated, then recanalizes

35

duodenal stenosis

partial occlusion of duodenal lumen, due to incomplete recanalization from defection vacuolization

causes back up in stomach and so stomach contents/bile are vomited

36

duodenal atresia

complete occulsion, very atretic, so hardly any duodenum; in segment, and no recanalization

can happen in 1 or more duodenum segments

20-30% of cases- associated with Down syndrome

37

polyhydramnios

duodenal atresia that causes build up of excess amniotic fluid in amniotic cavity, so on U/S see dark bubble next to stomach

38

hepatic (ventral) diverticulum in foregut occurs/becomes

week 4, becomes liver (large part) and gall bladder (small part)

39

induction for hepatic diverticulum

fibroblast growth factors from heart that act on bipotential cells

40

derivation of hepatic diverticulum

epithelium, distal end of foregut

41

derivates of mesdoerm of septum transversum

hematopoietic cells, kupffer cells, conenctive tissue cells

42

derivation of ventral mesentery

mesoderm of septum transversum that becomes lesser omentum and falciform ligament

43

derivation of common bile duct

connection between hepatic diverticulum and foregut

44

gall bladder function

stores secretions from liver, emulsifies lots of fatty type foods

45

kupffer cells

liver macrophages derived from mesenchyme in septum transversum

46

derivatives of mesenchyme in septum transversum

kupffer cells and hematopoetic tissue

47

derivatives of endodermal cells in hepatic diverticulum

hepatic cords > sinusoids

48

right or left lobe of liver bigger?

right

49

hematopoiesis in liver occurs

6 weeks

50

bile formation in liver occurs

12 weeks

51

stalk of diverticulum derivative

cystic duct

52

bile duct connects

hepatic and cystic ducts to duodenum

53

movement of common bile duct

entrance of common bile duct moves posteriorly with stomach rotation

54

ventral mesentery derivatives that persist

falciform ligament, lesser omentum = hepatogastric ligament, hepatoduodenal ligament

55

hepatogastric ligament connects

liver to abdominal wall

56

ventray mesentery forms

visceral peritoneum of liver

57

accessory hepatic ducts

variation in liver lobulation, usuall asymptomatic, matters during surgery

58

extrahepatic biliary atresia

1:10000 to 1:15000 incidence; due to failure of ducts to canalize or fetal infection

59

pancreas derivation

2 bus of foregut endodermal cells

60

how pancreas forms

duct of dorsal (larger) bud and ventral bud of foregut rotate posteriorly, fuse, form main pancreatic duct

61

location of pancreas

dorsal abdominal wall

62

growth factor for ventral pancreatic bud

FGF-2

63

growth factor for dorsal pancreatic bud

notochord secretes activin and FGF-2

64

exocrine histogenesis of pancreas

endodermal tubules branch, form acinar cells and ducts

65

endocrine histogenesis of pancrease

clumps of cells from exocrine part form islets

66

annular pancreas

if portion of ventral pancreatic bud that goes anteriorly improperly fuses around duodenum, causes duodenal obstruction

67

derivation of spleen

mesenchyme within dorsal megogastrium

68

gastrosplenic ligament

connects stomach to spleen

69

spleen functions

hematopoiesis, immune system

70

accessory spleen

10% incidence, associated w/ heart disease