Embryology of the GI Flashcards Preview

Alimentary System > Embryology of the GI > Flashcards

Flashcards in Embryology of the GI Deck (56)
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1
Q

What gene is a transcription factor for establishing left sideness?

A

PTX2

2
Q

What is Gastrulation?

A

Gastrulation is when the single-layered blastula is reorganised into a multilayered structure known as the gastrula

3
Q

What are the 3 main components for forming the trilaminar germ disk?

A

Gastrulation

CNS induction

Neurulation

4
Q

What occurs during gastrulation?

A

The bilaminar disc is converted into the trilaminar disc

5
Q

What are the 3 phases of embryo development

A
  1. Growth/proliferation
  2. Morphogenesis
  3. Differentiation
6
Q

What are teratogens?

A

Agent of factor that can cause harm to the embryo e.g. drugs

7
Q

What main drug may cause major congenital anomalies?

A

Thalidomide

8
Q

What are the components of the trilaminar disc?

A

Embryonic ectoderm

Embryonic endoderm

Embryonic mesoderm

9
Q

What does the embryonic ectoderm form?

A
Skin
CNS,PNS 
Sensory epithelia of the eye 
Ear 
Nose 
Sweat glands enamel of teeth 
Liver ( except the parenchyma)
Adrenal medulla 
ETC...
10
Q

What does the embryonic endoderm form?

A
Epithelial lining of RS
GIT
Glands 
Liver
Pancreas 
Urinary bladder 
ETC...
11
Q

What does the embryonic mesoderm form?

A
Muscle 
Bones 
Cartilage 
Dermis 
Vascular system 
Urogenital system except bladder 
Spleen 
Suprarenal gland cortex 
ETC...
12
Q

What gives rise to parietal and visceral mesoderm?

A

Lateral plate mesoderm

13
Q

What does the gut tube form from during the 3rd and 4th week?

A

The endoderm lining of the yolk sac

14
Q

What forms the urethra and bladder?

A

Allantois

15
Q

What does the esophagus form from?

A

Develops from the cranial part of the primitive gut tube

16
Q

What does the Laryngo-tracheal diverculum (lung bud) develop from?

A

It develops from the ventral wall of the foregut

17
Q

What does the tracheo-esophageal septum (ridge) divide?

A

Divides the foregut tube (endoderm lined) into trachea and esophagus

18
Q

What happens in the 4th week to the foregut?

A

The foregut dilates to form the stomach

19
Q

What rotation does the stomach undergo to create a final adult position?

A

An arterio-posterior rotation

20
Q

The stomach is attached to both the dorsal and ventral wall by a mesentary called what?

A

Mesogastrium

21
Q

What does rotation along the longitudinal axis pulling the dorsal mesentary to the left create?

A

The omental bursa (lesser sac)

22
Q

What is pulled to the right during the creation of omental bursa (lesser sac)?

A

Ventral mesogastrium

23
Q

What does the duodenum form from?

A

Formed from the caudal part of the foregut and the cranial part of the midgut

24
Q

What is the blood supply of the duodenum formed from?

A

Formed from the caudal part of the foregut and the cranial part of the midgut

25
Q

What is the blood supply of the duodenum?

A

Coeliac trunk and superior mesenteric artery

26
Q

What does retroperitoneal mean?

A

Situated or occuring behind the peritoneum

27
Q

When does the liver bud appear?

A

Middle of the 3rd week

28
Q

What does the liver bud give rise to?

A

The liver bud gives rise to the gallbladder and bile ducts, as well as to the parenchyma of the liver

29
Q

What forms the bile duct?

A

Connection between the liver bud and foregut (duodenum) narrows to form bile duct

30
Q

What forms the gall bladder and cystic duct?

A

Ventral outgrowth from the bile duct forms the gall bladder and cystic duct

31
Q

What does connective tissue always form from?

A

Mesoderm

32
Q

Foregut (spleen): What occurs at the end of the 4th week?

A

A mesenchymal condensation develops in the dorsal mesogastrium near the body wall

33
Q

Foregut (spleen): What occurs during the 5th week?

A

The mesenchyme differentiates to form the spleen

34
Q

What is spleen derived from?

A

The spleen is a mesodermal derivative

35
Q

What is a falsiform ligament?

A

A ligament attaches the liver to the front body wall, and separates the liver into the left lobe and right lobes.

36
Q

What does the pancreas form from?

A

It forms from the 2 buds, which grow from the endodermal lining of the duodenum in week 5.

37
Q

What 2 things fuse to form the pancreas?

A

Dorsal and Ventral buds

38
Q

What is the main pancreatic duct composed of?

A

Ventral duct + Distal part of dorsal duct

39
Q

What occurs if the tracheo-esophageal septum deviates incorrectly?

A

Then there is an incomplete separation of laryngo-tracheal tube (lung bud)

40
Q

What is it called if the ventral bud fails to migrate around the duodenum correctly?

A

Annular pancreas

  • This may cause duodenal stenosis
41
Q

What is the midgut?

A

The distal part of duodenum, jejunum, ileum, caecum, appendix, ascending colon, proximal 2/3rds of the transverse colon

42
Q

What does the development of the midgut involve?

A

It involves rapid elongation of the gut tube and its associated mesentary

  • Described as the ‘primary intestinal loop’
43
Q

What part of the primary intestinal loop will become the distal duodenum, jejunum and proximal ileum?

A

The Cephalic part of the primary intestinal loop

44
Q

What part of the primary intestinal loop becomes the distal ileum, caecum, appendix, ascending colon and the proximal 2/3rds of the transverse colon?

A

The Caudal part of the primary intestinal loop

45
Q

What week does the rotation of the midgut begin?

A

6th week

know this

46
Q

Where does the initial rotation of the primary intestinal loop occur?

A

It occurs around the axis of the superior mesenteric artery

47
Q

What is physiological herniation of the midgut?

A

As the 90 degree rotation occurs, the gut tube herniates into the extraembryonic cavity in the umbilical cord

48
Q

What is Omphalocele?

A

It is the herniation of abdominal viscera through an enlarged umbilical ring

  • Failure of retraction of umbilical ring
49
Q

What is Gastrochisis?

A

Herniation of abdominal contents directly through the body wall into the amniotic cavity

  • Through a weak area right of umbilicus
50
Q

What does the remnants of vitelline duct form?

A

Forms meckels’s diverticulum

  • May form fistula or vitelline cyst/ligament
51
Q

What is the hindgut?

A

Distal 1/3rd of transverse colon, descending colon, sigmoid colon, rectum and upper part of the anal canal.

  • Endoderm of hindgut also forms the lining of the bladder and urethra.
52
Q

What part of the hindgut joins with the posterior part of the cloaca (primitive anal canal)?

A

The terminal portion of the hindgut joins with the posterior part of the cloaca.

53
Q

What is the Enoderm/ectoderm boundary?

A

It is the cloacal membrane

54
Q

What artery supplies the Foregut?

A

Coeliac artery

55
Q

What artery supplies the Midgut?

A

Superior mesenteric artery

56
Q

What artery supplies the Hindgut?

A

Inferior mesenteric artery