Development of the Gut Flashcards Preview

Digestive System > Development of the Gut > Flashcards

Flashcards in Development of the Gut Deck (52)
Loading flashcards...
1

Foregut goes from

pharynx to proximal 1/2 duodenum

2

midgut goes from

distal 1/2 duodenum to proximal 2/3 transverse colon

3

Hindgut goes from

distal 1/3 transverse colon to proximal 2/3 anal canal

4

How do we start off life?

bi-laminar disc of epiblast and hypoblast

5

Epiblast becomes

ectoderm

6

hypoblast becomes

endoderm

7

What creates the third layer between ectoderm and endoderm

mesoderm

8

oropharangeal membrane

eventually forms the mouth. At the cranial end. Ectoderm of the stomodeum. Rupture ~week 4

9

what does ectoderm become?

Anything skin

10

endoderm

the gut tract/ anything mucosa

11

mesoderm

blood vessels/nerves

12

What is mesenchyme?

undifferentiated stem cells

13

What are the two types of folding in the gut?

Longitudinal and transverse

14

Transverse folding

ectoderm and mesoderm fold laterally and ventrally, which close off endoderm forming a seperate gut tube layer.
endoderm > epithelial lining
mesoderm > supporting structures and SM
outer mesenchymal layer > outer tissue layer

15

Longitudinal Folding

~17-18 days. opening between gut tube and yolk sac draws closed like a drawstring bag.
Divides into foregut, midgut (open to yolk sac) and hindgut
With further folding yolk sac opening gets smaller and smaller and gut sections become more defined.

16

What are the two transitional regions between endoderm (mucosal) and ectoderm (skin)?

oropharangeal membrane (mouth)
anal membrane (anys)

17

anal membrane

Eventually forms the anus. At the caudal end, ectoderm of the anal pit. ~ week 8 ruptures.

18

What is weird about the development of the gut tube lumen?

Initially the gut tube = oatent
As epithelium proliferates, it plugs up the lumen.
~ week 8 recanalization occurs

19

Arterial supply to FOREGUT

Celiac Trunk located @ T12

20

Arterial supply to MIDGUT

Superior Mesenteric Artery @ L1

21

Arterial supply to HINDGUT

Inferior Mesenteric Artery @ L3

22

Whats interesting about SMA

It goes all the way through the yolk sac and maintains a connection with the umbilical system

23

Why is the arterial supply of value?

Because it indicates the lymphatics and veins

24

Is the lungs endoderm or ectoderm, and why?

Endoderm. Because everything that secretes mucus is from endodermal origin.

25

How are the lungs formed?

Via a respiratory divaticulum, where the lungs bud of the oesophagus, eventually separating.

26

Oesophagus formation?

Starts as small tube immediately caudal to pharynx.
seperates from trachea to form oesophagus.
Rapidly elongates downwards.

27

What are some forms of oesophagus congenital malformations?

1) Tracheoesophageal Fistula (abnormal connection) = 'punches its way into trachea
2) Tracheoesophageal Atresia (blockage) = end up with blind end, baby starts vomiting up milk
3) Congenital Hiatal hernia= short oesophagus, stomach herniates into thorax, through oesophageal hiatus

28

What does the stomach sit between

Ventral and dorsal mesogastrium

29

Stage 1 of stomach formation

Gut tube starts to dilate

30

Stage 2 of stomach formation

-Dilation cont.
- rotation on long axis ~90 degrees clockwise
- Ventral mesogastrium moves to right
-dorsal mesogastrium moves left