Lecture 6 (GI and Respiratory Development) Flashcards

1
Q

The gut tube forms in week ______ thanks to:

A

3, body folding and the enveloping of the yolk sac

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2
Q

The stomach begins to form and rotate during week:

A

5

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3
Q

What things begin sprouting from the foregut region in week 5?

A

cystic diverticulum, ventral and dorsal pancreatic buds, and liver cords

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4
Q

In week 6, the stomach hs:

A

completed its rotation

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5
Q

The cloaca has formed by day:

A

35

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6
Q

In week _____, the primary intestinal loop has:

A

7

herniated into umbilicus and undergone initial 90-degree rotation

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7
Q

In week 11, the midgut undergoes additional rotation. How far? Where does it end up?

A

180 degrees

retracts back into the abdomen

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8
Q

In what direction do the primary intestinal loop and midgut rotate?

A

counterclockwise

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9
Q

BY what week do the duodenum, pancreas, ascending colon, and descending colon becomes fixed to the body wall?

A

week 12

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10
Q

When does the respiratory diverticulum form?

A

week 4

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11
Q

By the end of wk _____ the respiratory diverticulum does what?

A

4, into 5

it branches into left and right bronchial buds

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12
Q

The stem of the respiratory diverticulum will:

A

differentiate into the trachea and larynx

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13
Q

Development of the lung structures continue until:

A

the 8th year of life

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14
Q

What molecules specify the foregut?

A

WNT antagonists

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15
Q

What molecules specify the hindgut?

A

WNT, FGF, BMP and RA signaling

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16
Q

What gene is the backbone for GI development?

A

Hoxa-2

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17
Q

What Hoxa genes pattern the pharynx?

A

3 and 4

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18
Q

What Hox genes pattern the esophagus and trachea?

A

Hoxa 3 and 4, Hoxb 4-5 and Hoxc4-5

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19
Q

What Hox genes pattern the stomach?

A

Hoxa4-7, Hoxb 5, Hoxc %

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20
Q

What transcription factor is only expressed in the stomach?

A

Barx-1

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21
Q

What signaling molecules specify the midgut?

A

FGF4, 10 and WNT-5a

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22
Q

Pdx-1 is associated with the development of what system/organs?

A

glandular (pancreas, liver, etc.)

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23
Q

The gut tube is divided into what 4 regions?

A

pharyngeal gut
foregut
midgut
hindgut

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24
Q

When does the dorsal portion of the esophagus lengthen rapidly?

A

8th week

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25
Q

the upper 2/3 of the esophagus is innervated by the

A

vagus nerve

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26
Q

lower 1/3 of the esophagus is innervated by the

A

splanchnic plexus

27
Q

The lung bung forms from the foregut thanks to what signaling?

A

RA gradient that leads to the expression of TBX4

28
Q

What happens to the stomach in weeks 4-5?

A

it rotates 90 degrees with the foregut

29
Q

What happens to the stomach in week 6?

A

the posterior portion enlarges (greater curvature)

30
Q

What happens to the stomach in weeks 11-12?

A

establishes axis, places proximal part to left and distal part to right

31
Q

What connects stomach to dorsal body wall?

A

dorsal mesogastrium

32
Q

What connects stomach to ventral body wall? What is in this?

A

ventral mesentary

encloses liver

33
Q

What connects liver to ventral body wall?

A

falciform ligament

34
Q

the stomach’s rotation creates what two spaces?

A

lesser sac and greater omentum

35
Q

What other organs are embedded in the dorsal mesogastrium?

A

spleen and tail of pancreas

36
Q

When does the spleen form?

A

4 weeks

37
Q

What genes are required for the development of the spleen?

A

cooperative action of Pod1 and Bapx-1 in presence of Pbx-1

38
Q

When do hematopoietic cells move into the spleen?

A

3rd and 5th months

39
Q

What do the intestines originate from?

A

posterior part of the fore-, mid-, and hindgut

40
Q

at 5 wks, the midgut is enhanced by:

A

FGF-9

41
Q

What causes the intestinal tube to elongate in the 6th week?

A

WNT5a, Pdx-1, and Cdx-2

42
Q

When does intestinal herniation occur?

A

by weeks 6-7

43
Q

when is the body cavity large enough to accommodate the intestinal tract?

A

by week 9

44
Q

When and where does the primordial cecum appear?

A

6th week in caudal limb of midgut

45
Q

What molecules interact to form the cecum?

A

Hox genes, Cdx-2, FGF9 from the epithelium

FGF10 from mesoderm

46
Q

When is the cloaca divided into the rectum and urogenital sinus?

A

6th and 7th week

47
Q

What gives rise to the enteric ganglia? From what somite levels? Under the influence of?

A

neural crest cells
somites 1-7
influence of GDNF

48
Q

What signaling molecules cause cells to differentiate into either hepatic progenitor or pancreas and biliary progenitors?

A

hepatic: high FGF/BMP

pancreas and billary: low FGF/BMP

49
Q

Liver cords result from:

When does this occur?

A

Hhex and other TFs causing the downregulation of E-cadherin. they then migrate through the basal lamina

around day 21

50
Q

What signaling molecules are involved int he differentiation of the liver?

A

HGF, BMP,FGF, and WNT -> hepatoblasts

HNF and Fox-A -> hepatocytes

Cholangiocytes arise from TGF-beta and Notch in the ductal plate that’s influencde by Sox9

51
Q

Pancreatic progenitor cells express:

A

Pdx-1 and Hoxb-9

52
Q

How many different types of mature pancreas cells are there?

A

4

53
Q

When do Omphaloceles occur

A

When the gut tube fails to return to the body cavity after umbilical herniation

54
Q

When does the vitelline duct normally degenerate?

A

btwn 12th and 14th week

55
Q

What are the major steps in lung formation?

A

lung bud formation

branching

vascularization

gas exchange

postnatal growth

56
Q

What molecular patterning is responsible for the lung bud?

A

tip mesenchym expresses TFs in response to RA dn TBX4/5

TGFb1 limites FGF at tip

FGF10 laterally promotes growth of buds

57
Q

What are the stages of lung development and their corresponding weeks?

A
embryonic (4-7)
pseudoglandular (8-16)
Canalicular (17-26)
Terminal sec (26-birth)
Postnatal
58
Q

What happens in the lungs the last 4 wks of pregnancy?

A

massive increase of surface area in alveoli

59
Q

What molecule in the lungs increases the likelihood of survival if born premature?

A

surfactant

60
Q

In what lung stage does the pulmonary arterial system begin to form?

A

pseudoglandular

61
Q

Which type of alveolar cells are responsible for gas exchange?

A

type 1

62
Q

what do type II alveolar cells do? When do they arise?

A

produce surfactant

6.5-7 months

63
Q

premature infants are at risk for developing what due to their immature lungs?

A

RDS