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 Gastrointestinal Associated Organs > Flashcards

Development of Gastrointestinal Associated Organs Flashcards

1
Q

What is the epithelial lining of the gut tube derived from?

How does this affect the development of GIT-associated organs?

A

The epithelial lining is derived from endoderm

Other than the spleen, most GIT-associated organs are derived from endoderm

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

How are the liver, gallbladder and pancreas formed?

A

They are outpocketings of endoderm in the cranial half of the duodenum

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

What is duodenal papilla?

A

It delineates the change between the embryological foregut and midgut

It is the region where secretions from the accessory organs are emptied into the 2nd half of the duodenum

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

During which week does the liver begin to develop?

How does it first appear?

A

week 3

it appears as an outpouching of endoderm from the foregut

This is the hepatic diverticulum (liver bud)

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

What is the liver bud often called?

A

An endodermal plate

It is thickening of the endoderm at the cranial end of the duodenum

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

What happens to the rapidly dividing cells in the hepatic diverticulum?

A

They penetrate the septum transversum

this goes on to form the diaphragm

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

Why does the liver contain some cells of mesodermal origin?

A

The septum transversum is of mesodermal origin

Some of the mesodermal cells become encompassed within the liver

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

What is formed from the connections between the hepatic diverticulum and the duodenum?

A

The bile duct

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

What will endodermal cells develop into in the liver?

A

Endodermal cells develop into hepatocytes (parenchyma) of the liver

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

What will be derived from the mesoderm of the septum transversum?

A

Haematopoietic cells

Kupffer cells

connective tissue

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

What is the primary function of the liver in the developing foetus?

Why is this different in an adult?

A

Haematopoiesis - making blood cells

The liver of a foetus does not need to process metabolites from digestion as the mother does this

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

Why does the function of the liver change after birth?

A

The baby must process the nutrients from the GI tract and make them usable

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

What happens to haematopoiesis after birth?

A

It shifts to the bone marrow instead

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

Why does the midgut herniate into the Vitelline duct?

A

The liver continues to rapidly expand, as does the small intestine

There is not enough space for both of them

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

What happens when the liver can no longer be contained within the septum transversum?

A

It protrudes into the ventral mesentery and divides it into 2 parts:

  1. falciform ligament
  2. lesser omentum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where do the falciform ligament and lesser omentum run to and from?

A

The lesser omentum runs from the stomach to the liver

The falciform ligament runs from the liver to the ventral wall

They are both derivatives of the ventral mesentery

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

As the liver grows caudally, what is it in contact with?

What does this lead to?

A

The cranial part of the liver is in contact with the septum transversum

As they are so closely related, the bare area of the liver does not have any peritoneal covering on it

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

What happens to the mesoderm on the surface of the liver?

A

It differentiates into the visceral peritoneum, except on the cranial surface

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

What happens to the cranial surface of the liver during differentiation of the mesoderm?

A

It becomes the bare area of the liver as it remains in contact with the septum transversum

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

What forms around the margins of the bare area?

What are they formed from?

A

The peritoneum reflects to form anterior and posterior coronary ligaments

These are formed from mesoderm

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

What are the triangular ligaments formed from?

A

Where the anterior and posterior coronary ligaments meet at the lateral edges of the liver

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

What is the % of body weight taken up by the liver during week 10 of development?

How does this change after birth?

A

At week 10, the liver is 10% of total body weight

This decreases to 5% after birth

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

When does the gallbladder form?

What does it form from?

A

Forms at the end of week 3

a ventral outgrowth of the bile duct forms the gallbladder and cystic duct

this is an endodermal thickening

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

When does the foetus start producing bile?

What happens to it?

A

The liver starts producing bile in week 12

This is released into the GI tract but it has nowhere to go until the baby is born

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

What is the meconium?

A

The first bowel movement of the newborn

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

What colour is the meconium and why?

A

It is dark green in colour

This is due to the high concentration of bile

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

What happens to bilirubin prior to birth?

A

Bilirubin crosses the placenta and is removed by the mother’s circulation

28
Q

What happens to bilirubin after birth?

Why is this necessary?

A

The liver conjugates bilirubin

This makes it water-soluble

It can then be excreted into the GI tract through the biliary system

29
Q

What is the enzyme needed to conjugate bilirubin?

A

Glucuronosyltransferase

30
Q

What happens if the immature liver does not contain enough glucuronosyltransferase?

A

Bilirubin cannot be sufficiently conjugated and secreted

It accumulates - hyperbilirubinaemia

This leads to neonatal jaundice

31
Q

What are the characteristic signs of neonatal jaundice?

A

Yellow skin and sclera

32
Q

What is the main complication of neonatal jaundice if it is untreated?

A

If the bilirubin builds up in the blood supply, it can cross the blood-brain barrier and cause problems with development of the brain

This is kernicterus

33
Q

How is neonatal jaundice treated?

A

Phototherapy (light therapy)

Blue light is the most effective

34
Q

How can phototherapy prevent the risks of kernicterus?

A

Phototherapy oxidises bilirubin to a water-soluble form that can be easily excreted

35
Q

What causes biliary atresia?

A

Failure of the hepatic or bile duct to recanalise

36
Q

What happens during recanalisation of the hepatic and bile ducts?

A

Cells in the tube proliferate quickly to fill the tube and make it a solid structure

Apoptosis then forms small holes in the tube

These holes join together to make a hollow lumen

37
Q

how many births are affected by biliary atresia?

A

1 in 15,000

38
Q

What is biliary atresia and what does it lead to?

A

The bile duct is narrowed, leading to a distended hepatic duct

39
Q

Why is biliary atresia often initially treated with phototherapy?

A

It presents with symptoms which are indistinguishable from neonatal jaundice

40
Q

How can biliary atresia be distinguished from neonatal jaundice?

A

As soon as phototherapy stops, the symptoms of jaundice will return

41
Q

What causes duplication of the gallbladder?

A

An extra endodermal outpocketing during weeks 5 and 6

This leads to formation of 2 gallbladders

42
Q

What are the symptoms of duplication of the gallbladder?

A

It is usually asymptomatic

43
Q

What does the pancreas initially develop as?

A

2 endodermal buds which fuse together

These are the dorsal and ventral buds

44
Q

Which pancreatic endodermal bud develops first?

How does it develop?

A

The dorsal bud appears in week 3

It is an outpocketing of the duodenum that extends into the dorsal mesentery

45
Q

Where does the ventral bud develop?

A

The ventral bud is a smaller diverticulum that is caudal to the developing gallbladder

46
Q

What happens as the stomach and duodenum rotate 90o to the endodermal buds?

A

The ventral bud is carried dorsally along with the bile duct

It will fuse with the inferior edge of the dorsal bud during week 6

47
Q

What do the dorsal and ventral buds give rise to?

A

The dorsal bud gives rise to the head, body and tail of the pancreas

The ventral bud gives rise to the uncinate process

48
Q

What are the connective tissue and blood vessels surrounding the pancreas formed from?

A

Mesoderm

49
Q

What happens to the ductal systems when the dorsal and ventral buds fuse?

A

Their ductal systems become interconnected

50
Q

What is the main pancreatic duct formed from?

A

The distal portion of the dorsal pancreatic duct and ALL of the ventral pancreatic duct

51
Q

what is the accessory pancreatic duct formed from?

What is significant about this?

A

Formed from the proximal portion of the dorsal pancreatic duct

It is often obliterated during development

52
Q

Where does the main pancreatic duct enter the duodenum?

A

The main pancreatic duct and bile duct enter the duodenum at the Ampulla of Vater

This is the major duodenal papilla

53
Q

How is the Ampulla of Vater controlled?

A

Contraction and relaxation of the sphincter of Oddi to allow secretions into the second part of the duodenum

54
Q

Where would the accessory pancreatic duct enter the duodenum?

A

at the minor duodenal papilla

55
Q

What condition results from a bilobed ventral pancreatic duct?

How does this happen?

A

One lobe may migrate ventral to the duodenum and one love may migrate dorsally to surround the duodenum

This leads to annular pancreas

56
Q

What is the consequence of annular pancreas?

A

It compresses the duodenum and causes gastrointestinal obstruction

57
Q

What is meant by ectopic pancreatic tissue?

A

Inappropriate differentiation of endodermal cells into pancreatic tissue

This leads to pancreatic tissue being in places where it shouldn’t

58
Q

Where is ectopic pancreatic tissue found?

A

Anywhere from the distal oesophagus to the tip of the primary intestinal loop

It is most frequently in the duodenum or stomach muscosa

59
Q

What are the symptoms of ectopic pancreatic tissue?

A

It is usually asymptomatic

If the tissue begins to secrete enzymes, it begins to degrade the gut tube wall

This leads to ulceration or haemorrhage

60
Q

When does the spleen first appear?

From what is it derived?

A

It appears in week 5

It is a mesenchymal condensation in the dorsal mesentery

It is derived from mesoderm

61
Q

What is mesenchyme?

A

Undifferentiated mesoderm

62
Q

How does rotation of the stomach affect the spleen?

A

Rotation of the stomach brings the spleen over to the left-hand sidee

63
Q

How does the spleen divide the dorsal mesentery?

A

The gastrosplenic ligament is between the stomach and the spleen

The lienorenal (splenorenal) ligament is between the spleen and kidney

64
Q

What causes an accessory spleen?

How common are they?

A

Additional mesenchymal condensations may occur in the dorsal mesentery

10% of the population have an accessory spleen

65
Q

Where do accessory spleens usually form?

A

Near the hilum of the primary spleen

66
Q

What are they symptoms of an accessory spleen?

Why is it important to recognise?

A

Usually asymptomatic

It can affect the interpretation of medical images

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