Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Yr 2 - GI & Metabolism > Embryology - Development of Foregut > Flashcards

Embryology - Development of Foregut Flashcards

1
Q

Where does the foregut start/end?

A

Oesophagus to duodenum (first bit of SI)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When is the primitive gut tube formed?

A

During embryonic folding - the ventral surface becomes concave in two directions. The sides of the embryo fold in on each other and the head and tail fold toward one another, forming the primitive gut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where does the primitive gut tube extend to/from?

A

From the oropharyngeal membrane to the cloacal membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What can the primitive gut tube be divided into during foetal life?

A
  1. Foregut 2. Midgut 3. Hindgut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where does the midgut start/end?

A

2nd half duodenum to 2/3 along transverse colon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where does the hindgut start/end?

A

Distal 1/3 transverse colon to superior 2/3 rectum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When does cranio-caudal folding occur?

A

Week 3-4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What connects the gut tube to the yolk sac?

A

Vitelline duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is the midgut continuous with the yolk sac?

A

At the vitelline duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where is the epithelial lining of the primitive gut tube derived from?

A

The endoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where is the smooth muscle and connective tissue of the primitive gut tube derived from?

A

The surrounding visceral mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does the visceral and parietal mesoderm also give rise to?

A

The visceral and parietal peritoneum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is the primitive gut tube suspended from the posterior abdominal wall?

A

By the dorsal mesentery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a mesentery?

A

A double fold of peritoneum that encloses an organ and connects to the body wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the organs enclosed by a mesentery called (e.g. gut)?

A

Intraperitoneal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the organs not surrounded by peritoneum called (e.g. aorta)?

A

Retroperitoneal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is function of mesentery?

A

Acts as route for blood supply, nerve supply and lymphatic drainage for organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where is the dorsal mesentery?

A

From lower oesophagus to cloaca

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where is the ventral mesentery?

A
  • From lower oesophagus to 1st part of duodenum - Forms lesser omentum and falciform ligament (umbilical vein)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What do vitelline arteries give rise to?

A

Arteries of GIT The vitelline arteries undergo remodelling, losing their connection to the yolk sac to supply the gastrointestinal tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Directly from the aorta, what unpaired arteries supplying the GIT arise?

A
  1. Coeliac trunk –> foregut 2. Sup mesenteric artery –> midgut 3. Inf mesenteric artery –> hindgut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is the definitive gut formed?

A

Hollow primitive gut tube –> gut tube occluded by proliferation of endoderm derived epithelial lining –> apoptosis of epithelium occurs over next 2 weeks creating vacuoles –> recanalisation (vacuoles coalesce to fully recanalise the gut tube –> definitive hollow gut tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When does proliferation of the endoderm derived epithelial lining that occludes the gut tube occur?

A

Week 6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

When do vacuoles coalesce to fully recanalise the gut tube by?

A

Week 9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is purpose of hollow tube becoming occluded then hollowed again?

A

How specialised cells are formed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What can abnormal recanalisation lead to?

A

Duplications of the GI tract –> cyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What can incomplete recanalisation lead to?

A

Stenosis (narrowing) or blockage (atresia) of the gut tube

28
Q

What is most commonly affected by abnormal recanalisation?

A

Ileum is most commonly affected followed by duodenum

29
Q

What can duplication cysts lead to?

A

Bowel obstruction or intussusception (telescoping of proximal part of bowel into distal part)

30
Q

What does the foregut give rise to?

A

Respiratory diverticulum

31
Q

How is the foregut separated from the respiratory diverticulum?

A

Tracheoesophageal ridges form tracheoesophageal septum (separating trachea and oesophagus)

32
Q

What occurs when an oesophageal atresia occurs independently of a TOF?

A

Displacement of the tracheoesophageal septum separates proximal and distal ends of oesophagus

33
Q

What are dangers of oesophageal atresia?

A

This prevents the foetus from swallowing amniotic fluid and returning it to the mother through the placental circulation – polyhydramnios

34
Q

How are oesophageal atresia’s repaired?

A

Surgical repair results in 85% survival rate

35
Q

When/where does the oesophagus form?

A

Week 4 caudal to the lung bud

36
Q

How does the oesophagus differ from the rest of the gut tube?

A
  • Like the rest of the gut tube, oesophagus has endodermal epithelial lining and smooth muscle layer from visceral mesoderm.
  • However, also has some skeletal muscle
37
Q

Where is the skeletal muscle of the oesophagus derived from?

A

The paraxial mesoderm

38
Q

What happens if the stomach doesn’t descend correctly? What is this called?

A

Some of stomach in thorax (supradiaphragmatically)

Congenital hiatal hernia

39
Q

How is a congenital hiatal hernia different from an adult acquired hernia?

A

Adult –> top part of stomach slides through opening into thorax due to pressure

Congenital –> failure of oesophagus to elongate

40
Q

When/how does the stomach appear?

A

In 4th week as a dilation of the foregut

41
Q

How is the stomach suspended in the abdomen?

A

By the dorsal and ventral mesenteries

42
Q

What is the lesser omentum?

A

Ventral mesentery that goes from lesser curvature of stomach to liver

43
Q

What is the falciform ligament?

A

From liver to anterior wall, derivative of mesentery

44
Q

How does the greater curvature form?

A

Differential growth in week 5 forms the greater curvature (i.e. the dorsal wall)

45
Q

How/when does the stomach rotate?

A

•In weeks 7-8, the stomach underdoes rotation around 2 axes

46
Q

How does the lesser curvature move during stomach rotation?

A

•90° clockwise rotation around the craniocaudal axis causes the lesser curvature to move from ventral position to the right.

47
Q

How does the greater curvature move during stomach rotation?

A

The greater curvature moves from dorsal position to the left

48
Q

How are the vagus nerves moved during stomach rotation?

A

The vagus nerves are initially located on left and right sides of the gut tube but are also rotated such that the left vagus trunk becomes anterior and the right becomes dorsal (posterior)

49
Q

There is also some rotation around the ventrodorsal axis. How does this affect the lesser/greater curvatures?

A
  • the greater curvature faces slightly caudally
  • the lesser curvature slightly cranially
50
Q

As the stomach rotates around the craniocaudal axis, it creates a space behind it. What is this called? What is the remaining peritoneal cavity now known as?

A

•the lesser peritoneal sac (omental bursa)

  • The greater sac
51
Q

What connects the greater and lesser sacs?

A

The epiploic foramen (of Winslow) –> a narrow opening

52
Q

What are greater and lesser peritoneal sacs created by?

A

Rotation of stomach

53
Q

How does the stomach attach to the posterior wall?

A

Via the dorsal mesentery (dorsal mesentery attached to the greater curvature of the stomach) and the posterior abdominal wall (dorsal mesentery) continues to grow rapidly.

54
Q

The dorsal mesentery folds back on itself to form what?

A

Reflects back on itself to form an extension of the lesser sac (omental bursa) –> 4 layers

55
Q

What does greater omentum attach to?

A

Posterior wall

56
Q

The ventral and dorsal folds fuse before birth. What does the posterior layer of the greater omentum also fuse with?

A

The mesentery of the transverse colon

57
Q

What is congenital pyloric stenosis?

A

Narrowing of pyloric sphincter caused by hypertrophy of smooth muscle

58
Q

Is pyloric stenosis more common in men or women?

A

More common in males 5:1

59
Q

What is effect of pyloris stenosis?

A
  • Restricts gastric emptying which can lead to dilation of the stomach
  • Signs include:

ØPalpable pyloric mass

ØProjectile vomiting

ØVisible peristalsis

60
Q

What can inappropriate epithelial differentiation of the gut tube lead to?

A

Ectopic gastric tissue

61
Q

What can ectopic gastric tissue lead to?

A
  • Due to acid production, this can cause inflammation and ulceration in the surrounding area
  • Damage can result in strictures due to scarring or rupture of the gut wall
62
Q

What is the duodenum continuous with?

A

Duodenum

63
Q

When does the duodenum elongate? What does it result in? What then happens?

A

Week 4 - resulting in a ventrally projecting C-shape

This is then dragged to the right by the rotating stomach

64
Q

What happens to the dorsal mesentery attached to the duodenum?

A

Degenerates so that the (majority) duodenum lies against the posterior abdominal wall – secondarily retroperitoneal

65
Q

What is oesophageal stenosis?

A
  • Occurs when the oesophagus fails to recanalise
  • Typically associated with polyhydramnios prenatally.
  • Postnatally, the child will regurgitate IMMEDIATELY upon feeding.
  • However, there is usually NOT a tracheoesophageal fistula, so the lungs will usually NOT be congested.

Yr 2 - GI & Metabolism (51 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions