Brainscape's Knowledge GenomeTM

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


See full index

BS - Gastrointestinal System pt.1 > Development of the Foregut > Flashcards

Development of the Foregut Flashcards

1
Q

During which process is the primitive gut tube formed?

Where does it extend from?

A

It is formed during embryonic folding

It extends from the oropharyngeal membrane to the cloacal membrane

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

During which weeks does cranio-caudual folding occur and what is the result is this?

A

weeks 3-4

it pushes the head and tail end in closer proximity due to the increased amount of amniotic fluid surrounding the embryo

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

What are the 3 parts of the primitive gut tube?

A
  1. foregut
  2. midgut
  3. hindgut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

From which regions does the foregut run?

A

The foregut runs from the mouth to the 1st part of the duodenum

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

From which regions does the midgut run?

A

The midgut runs from the 2nd half of the duodenum to 2/3 the way along the transverse colon

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

From which regions does the hindgut run?

A

The hindgut runs from the distal 1/3 of the transverse colon to the superior 2/3 of the rectum

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

What is significant about the 3 regions of the primitive gut tube?

A

Each region is supplied by a different artery and a different branch of the autonomic nervous system

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

What is the midgut continuous with?

A

The yolk sac at the vitelline duct

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

What happens during lateral body wall folding?

A

The lateral edges come towards the midline and fuse

They fuse everywhere except the level of the midgut

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

What does the surface ectoderm go on to form?

A

The epidermis of the skin

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

What does the endoderm go on to form?

A

The epithelial lining of the primitive gut tube

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

What is the smooth muscle and connective tissue in the primitive gut tube derived from?

A

the surrounding visceral mesoderm which covers the gut tube

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

What do the visceral and parietal mesoderm give rise to?

A

the visceral and parietal peritoneum

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

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

A

Through a double layer of peritoneum

This is the dorsal mesentery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
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
16
Q

What is an intraperitoneal organ?

A

An organ that is invested within the peritoneum

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

What is a retroperitoneal organ?

A

An organ that is not surrounded by the peritoneum

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

Where does the dorsal mesentery run to and from?

A

It runs from the lower oesophagus to the cloaca

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

What is the role of the dorsal mesentery?

A

It attaches the primitive gut tube to the posterior abdominal wall along its entire length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where does the ventral mesentery run to and from?

A

It runs from the lower oesophagus to the first part of the duodenum

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

What is the role of the ventral mesentery?

A

It attaches the foregut to the anterior abdominal wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the difference between the dorsal and ventral mesenteries?

A

The ventral mesentery is only present at the level of the foregut

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

What mesentery does the liver develop within?

A

The ventral mesentery

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

What are the 2 parts of the ventral mesentery?

How is it split?

A
  1. lesser omentum
  2. falciform ligament

It is split by the developing liver

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

Where does the lesser omentum run to and from?

A

It is the region between the stomach and the liver

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

Where does the falciform ligament run to and from?

A

it is the region between the liver and the anterior wall

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

What is the role of the mesenteries?

A

They act as suspension for the gut tube

They allow the passage of blood vessels, lymphatics and nerves to and from the organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the name of the plexus of blood vessels in the developing embryo?

A

vitelline arterial plexus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What happens when the vitelline arteries undergo remodelling?

A

They form the vessels that will supply the gut tube

They lose their connection to the yolk sac to supply the GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the branches of arteries that supply the GI tract?

A
  1. coeliac trunk supplies the foregut
  2. superior mesenteric artery supplies the midgut
  3. inferior mesenteric artery supplies the hindgut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What happens in week 6 of development?

A

Rapid proliferation of the endoderm derived epithelial lining occludes the gut tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What happens during recanalisation?

A

During week 7 and 8, apoptosis of the epithelium occurs to create vacuoles in the occluded gut tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What happens in week 9 of development?

A

The vacuoles coalesce to fully recanalise the gut tube

This forms the definitive gut tube lumen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Why is the process of recanalisation significant?

A

When the endoderm proliferates, the cells differentiate and become specialised

Apoptosis removes the cells which are not specialised

35
Q

What can abnormal recanalisation of the gut tube cause?

A

Duplications of the gastrointestinal tract

Stenosis or atresia of the gut tube

36
Q

What is the difference between stenosis and atresia of the gut tube?

How are they caused?

A

They are caused by incomplete recanalisation

Stenosis is narrowing of the gut tube

Atresia is blockage of the gut tube

37
Q

Which areas of the GI tract are most commonly affected by abnormal recanalisation?

Why does it occur?

A

Most commonly affects the ileum, followed by the duodenum

Problems occur when apoptosis goes slightly wrong

38
Q

What is the result of duplication of the gut tube?

What are examples?

A

Duplication cysts which are rare but have a high incidence of complications

e.g. bowel obstruction or intussusception

39
Q

When does intusussception occur?

A

When the ileum telescopes and folds back on itself

This leads to a narrowed opening

40
Q

Where does the foregut extend from and to?

What structure does it give rise to?

A

It extends from the oropharyngeal membrane to the first part of the duodenum

It gives rise to the respiratory diverticulum

41
Q

How does the foregut separate from the respiratory diverticulum?

A

It forms a tracheoesophageal septum

This separates the pharynx and the oesophagus from the trachea

42
Q

How does oesophageal atresia arise?

A

The tracheoesophageal septum may be displaced

This separates the proximal and distal ends of the oesophagus

The proximal part of the oesophagus ends in a blind-ended sac

43
Q

Why does the foetus ingest and swallow amniotic fluid during development?

A

It helps the kidneys start to function as they filter the fluid

It allows the respiratory muscles to be built up

44
Q

How does oesophageal atresia affect the ability of the foetus to ingest amniotic fluid?

A

It prevents the foetus from swallowing the amniotic fluid and returning it to the mother through placental circulation

45
Q

What condition does oesophageal atresia in the foetus lead to and why?

A

Polyhydramnios

It is caused by an excess of amniotic fluid

46
Q

During which week does the oesophagus form?

A

week 4

It forms caudal to the lung bud and begins as a short structure

47
Q

What features does the oesophagus share with the rest of the gut tube?

A
  1. endodermal epithelial lining

2. smooth muscle layer derived from visceral mesoderm

48
Q

From what is the skeletal muscle in the oesophagus derived from?

A

Paraxial mesoderm

49
Q

During which weeks does rapid elongation of the oesophagus occur?

What is the purpose of this?

A

weeks 4 - 7

this allows the oesophagus to descend into the abdomen, where it resides

if it did not occur, the stomach would reside in the thorax

50
Q

What happens in an adult hiatal hernia?

A

The stomach starts in the abdomen

An increase in abdominal pressure causes it to slide back into the thorax

51
Q

What happens in a congenital hiatal hernia?

A

There is insufficient elongation of the oesophagus

This leads to a portion of the stomach residing supradiaphragmatically

52
Q

How severe is a congenital hiatal hernia and how does it differ from an acquired hiatal hernia?

A

It has varying degrees of severity depending on how much of the stomach resides in the thorax

It differs from an acquired hiatal hernia as it is irreducible

53
Q

When and what as does the stomach appear?

A

It appears in week 4 as a dilatation of the foregut

54
Q

What is the stomach attached to?

A

It is attached to the anterior abdominal wall by the dorsal mesentery

It is attached to the liver by the lesser omentum (ventral mesentery)

55
Q

When does differential growth of the stomach occur?

What is this and what does it form?

A

Week 5

The dorsal aspect of the stomach grows very quickly in relation to the ventral aspect

This forms the gearter curvature of the dorsal wall

56
Q

What happens to the stomach during week 7-8?

A

It undergoes rotation around 2 axes

57
Q

What is the first rotation of the stomach around the craniocaudal axis?

What does this cause?

A

90o clockwise rotation around the craniocaudal axis

This causes the lesser curvature to move from the ventral position to the right

58
Q

How does the greater curvature change position during 90o clockwise rotation?

A

It moves from the dorsal position to the left

59
Q

Where are the vagus nerves located before rotation of the stomach?

A

On the left and right sides of the gut tube

60
Q

After 90o clockwise rotation of the stomach, where do the vagus nerves reside?

A

The left vagus trunk becomes anterior to the stomach

The right vagus nerve becomes dorsal to the stomach

61
Q

What does rotation of the stomach around the ventrodorsal axis lead to?

A

The greater curvature faces slightly caudally and the lesser curvature faces slightly cranially

62
Q

How are the lesser peritoneal sac and greater peritoneal sac formed?

A

As the stomach rotates around the craniocaudal axis, it creates a space behind it

This is the lesser peritoneal sac and the remaining peritoneal cavity is the greater peritoneal sac

63
Q

How are the greater and lesser peritoneal sacs connected?

A

Through a narrow opening called the epiploic foramen (of Winslow)

64
Q

What is an alternative name for the lesser peritoneal sac?

A

The omental bursa

65
Q

How does the liver move as the stomach rotates?

A

As the stomach rotates, the liver will rotate with it

It resides in the right-hand side of the body, in the lesser peritoneal sac

66
Q

How does the dorsal mesentery form an extension of the omental bursa?

A

The dorsal mesentery is attached to the greater curvature of the stomach and posterior abdominal wall

It continues to grow and folds back on itself

67
Q

How does the greater omentum form?

A

The ventral and dorsal folds of the dorsal mesentery fuse to cover the viscera

The greater omentum is made from 4 layers of peritoneum

68
Q

What does the posterior layer of the greater omentum fuse with?

A

the mesentery of the transverse colon

69
Q

How does the duodenum lose its layer of peritoneum during rotation of the stomach?

A

The first part of the duodenum is attached to the liver by the lesser omentum

Rotation pushes it against the posterior abdominal wall

As this happens, it loses its layer of peritoneum

70
Q

Which parts of the duodenum are retroperitoneal?

A

The first section is intraperitoneal

The other 3 parts of the duodenum are retroperitoneal

71
Q

What is the role of the pyloric sphincter?

A

It dictates when the stomach can open and empty

72
Q

What is pyloric stenosis and what does it affect?

A

Narrowing of the pyloric sphincter caused by hypertrophy of smooth muscle

This leads to a narrowing of the opening which affects gastric emptying

73
Q

How many births are affected by congenital pyloric stenosis?

Does it affect more males or females?

A

it affects 1 in 500 births

it is more common in males and affects 5 times more males than females

74
Q

What is the result of restricting gastric emptying in pyloric stenosis?

A

Dilation of the stomach

75
Q

What are 3 noticeable signs of congenital pyloric stenosis?

A
  1. palpable pyloric mass
  2. projectile vomiting
  3. visible peristalsis
76
Q

What is heterotopic gastric tissue and what is it a result of?

A

Inappropriate epithelial differentiation of the gut tube can result in ectopic gastric tissue

This is gastric tissue which is present outside of the stomach

77
Q

What is the result of heterotopic gastric tissue?

A

Acid production can lead to inflammation and ulceration of the surrounding area

Damage can result in strictures due to scarring or rupture of the gut wall

78
Q

What are the 2 origins of the duodenum?

A

The proximal half comes from the foregut

The distal half comes from the midgut

79
Q

What is the boundary of the 2 origins of the duodenum?

A

the boundary is distal to the entrance of the common bile duct

80
Q

What happens after secretions from the pancreas and the liver enter the duodenum?

A

After this point, the duodenum becomes midgut and is supplied by the superior mesenteric artery

81
Q

During which week does the duodenum elongate?

What is the result of this?

A

It elongates in week 4, leading to a ventrally projecting C-shape

It is then dragged to the right by the rotating stomach

82
Q

What processes occur prior to the duodenum becoming secondarily retroperitoneal?

A

The dorsal mesentery attached to the duodenum degenerates

The majority of the duodenum lies against the posterior abdominal wall

83
Q

Why is the duodenum ‘secondarily retroperitoneal’?

A

It started with a mesentery that degenerated during development

84
Q

Which blood vessels supply the duodenum?

A

The proximal half is supplied by the coeliac trunk

The distal half is supplied by the superior mesenteric artery

BS - Gastrointestinal System pt.1 (22 decks)

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