Lecture 6 (GI and Respiratory Development)

Question 1

The gut tube forms in week ______ thanks to:

Answer 1

3, body folding and the enveloping of the yolk sac

Question 2

The stomach begins to form and rotate during week:

Answer 2

5

Question 3

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

Answer 3

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

Question 4

In week 6, the stomach hs:

Answer 4

completed its rotation

Question 5

The cloaca has formed by day:

Answer 5

35

Question 6

In week _____, the primary intestinal loop has:

Answer 6

7

herniated into umbilicus and undergone initial 90-degree rotation

Question 7

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

Answer 7

180 degrees

retracts back into the abdomen

Question 8

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

Answer 8

counterclockwise

Question 9

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

Answer 9

week 12

Question 10

When does the respiratory diverticulum form?

Answer 10

week 4

Question 11

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

Answer 11

4, into 5

it branches into left and right bronchial buds

Question 12

The stem of the respiratory diverticulum will:

Answer 12

differentiate into the trachea and larynx

Question 13

Development of the lung structures continue until:

Answer 13

the 8th year of life

Question 14

What molecules specify the foregut?

Answer 14

WNT antagonists

Question 15

What molecules specify the hindgut?

Answer 15

WNT, FGF, BMP and RA signaling

Question 16

What gene is the backbone for GI development?

Answer 16

Hoxa-2

Question 17

What Hoxa genes pattern the pharynx?

Answer 17

3 and 4

Question 18

What Hox genes pattern the esophagus and trachea?

Answer 18

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

Question 19

What Hox genes pattern the stomach?

Answer 19

Hoxa4-7, Hoxb 5, Hoxc %

Question 20

What transcription factor is only expressed in the stomach?

Answer 20

Barx-1

Question 21

What signaling molecules specify the midgut?

Answer 21

FGF4, 10 and WNT-5a

Question 22

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

Answer 22

glandular (pancreas, liver, etc.)

Question 23

The gut tube is divided into what 4 regions?

Answer 23

pharyngeal gut
foregut
midgut
hindgut

Question 24

When does the dorsal portion of the esophagus lengthen rapidly?

Answer 24

8th week

Question 25

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

Answer 25

vagus nerve

Question 26

lower 1/3 of the esophagus is innervated by the

Answer 26

splanchnic plexus

Question 27

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

Answer 27

RA gradient that leads to the expression of TBX4

Question 28

What happens to the stomach in weeks 4-5?

Answer 28

it rotates 90 degrees with the foregut

Question 29

What happens to the stomach in week 6?

Answer 29

the posterior portion enlarges (greater curvature)

Question 30

What happens to the stomach in weeks 11-12?

Answer 30

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

Question 31

What connects stomach to dorsal body wall?

Answer 31

dorsal mesogastrium

Question 32

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

Answer 32

ventral mesentary encloses liver

Question 33

What connects liver to ventral body wall?

Answer 33

falciform ligament

Question 34

the stomach's rotation creates what two spaces?

Answer 34

lesser sac and greater omentum

Question 35

What other organs are embedded in the dorsal mesogastrium?

Answer 35

spleen and tail of pancreas

Question 36

When does the spleen form?

Answer 36

4 weeks

Question 37

What genes are required for the development of the spleen?

Answer 37

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

Question 38

When do hematopoietic cells move into the spleen?

Answer 38

3rd and 5th months

Question 39

What do the intestines originate from?

Answer 39

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

Question 40

at 5 wks, the midgut is enhanced by:

Answer 40

FGF-9

Question 41

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

Answer 41

WNT5a, Pdx-1, and Cdx-2

Question 42

When does intestinal herniation occur?

Answer 42

by weeks 6-7

Question 43

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

Answer 43

by week 9

Question 44

When and where does the primordial cecum appear?

Answer 44

6th week in caudal limb of midgut

Question 45

What molecules interact to form the cecum?

Answer 45

Hox genes, Cdx-2, FGF9 from the epithelium FGF10 from mesoderm

Question 46

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

Answer 46

6th and 7th week

Question 47

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

Answer 47

neural crest cells somites 1-7 influence of GDNF

Question 48

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

Answer 48

hepatic: high FGF/BMP | pancreas and billary: low FGF/BMP

Question 49

Liver cords result from: When does this occur?

Answer 49

Hhex and other TFs causing the downregulation of E-cadherin. they then migrate through the basal lamina around day 21

Question 50

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

Answer 50

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

Question 51

Pancreatic progenitor cells express:

Answer 51

Pdx-1 and Hoxb-9

Question 52

How many different types of mature pancreas cells are there?

Answer 52

4

Question 53

When do Omphaloceles occur

Answer 53

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

Question 54

When does the vitelline duct normally degenerate?

Answer 54

btwn 12th and 14th week

Question 55

What are the major steps in lung formation?

Answer 55

lung bud formation branching vascularization gas exchange postnatal growth

Question 56

What molecular patterning is responsible for the lung bud?

Answer 56

tip mesenchym expresses TFs in response to RA dn TBX4/5 TGFb1 limites FGF at tip FGF10 laterally promotes growth of buds

Question 57

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

Answer 57

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

Question 58

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

Answer 58

massive increase of surface area in alveoli

Question 59

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

Answer 59

surfactant

Question 60

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

Answer 60

pseudoglandular

Question 61

Which type of alveolar cells are responsible for gas exchange?

Answer 61

type 1

Question 62

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

Answer 62

produce surfactant 6.5-7 months

Question 63

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

Answer 63

RDS