Brainscape's Knowledge GenomeTM

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


See full index

Gastro-intestinal System > Embryology > Flashcards

Embryology Flashcards

1
Q

How does embryonic folding help development of the GI tract?

A

Creating a ventral body wall

Creating a tube within a cavity

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

In which week does the embryo fold?

A

4th

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

When the GI tube first develops, what does it look like?

A

A simple tube with 2 blind ends

1 opening at the umbilicus (midgut continuous with the yolk sac)

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

Where does the primitive gut tube run from and to?

A

Stomatodeum (future mouth) to the proctodeum (future anus)

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

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

A

Endoderm

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

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

A

Splanchnic mesoderm

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

Which parts of the GI tract are derivatives of the foregut?

A 
Oesophagus 
Stomach 
Pancreas
Liver
Gall bladder
Duodenum (to duodenal papilla)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which parts of the GI tract are derivates of the midgut?

A 
Duodenum (after duodenal papilla)
Jejunum 
Ileum 
Caecum 
Ascending colon 
Proximal 2/3 of the transverse colon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which parts of the GI tract are derivatives of the hindgut?

A 
Distal 1/3 of the transverse colon 
Descending colon 
Sigmoid colon 
Rectum 
Upper anal canal 
(Internal lining of the bladder and urethra)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the blood supply to each embryonic division?

A 
Foregut = coeliac trunk 
Midgut = superior mesenteric artery 
Hindgut = inferior mesenteric artery
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the blood supply to the duodenum

A

Proximal to duodenal papilla = gastroduodenal and superior pancreaticoduodenal (from the coeliac trunk)
Distal to duodenal papilla = inferior pancreaticoduodenal (from SMA)

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

Describe the blood supply to the head of the pancreas

A 
Superior pancreaticoduodenal (coeliac trunk)
Inferior pancreaticoduodenal (SMA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the intraembryonic coelom

A

Begins as one large cavity
Later subdivided by the future diaphragm into the abdominal and thoracic cavities
Peritoneal membrane lines the abdominal cavity

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

What is a mesentery?

A

A double layer of peritoneum suspending the gut tube from the abdominal wall
Allows a conduit for nerve and blood supply
Allow mobility where needed

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

How is the mesoderm formed?

A

Condensation of splanchnic mesoderm

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

Describe the greater omentum

A

Formed by the dorsal mesentery
Suspended by the greater curve of the stomach
First structure seen when the abdominal cavity is opened

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

Describe the lesser omentum

A

Formed by the ventral mesentery

Free edge of the portal triad

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

The rotation of the stomach contributes to the formation of the …

A

Greater and lesser sacs

Omenta

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

How is the lesser sac formed?

A

The right hand sac pushed posterior to the stomach due to the enlargement of the liver
(Left and right sac formed due to having a dorsal and ventral mesentery at the foregut)

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

Describe the rotation of the stomach

A

Around the longitudinal axis and then around the anterior-posterior axis
Puts the vagus nerve anterior and posterior to the stomach
Shifts cardia and pylorus from midline
Contributes to moving lesser sac behind the stomach
Creates the greater omentum

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

Describe secondary retroperitoneal

A

Began development invested by peritoneum

Mesentery is lost through fusion at the posterior abdominal wall

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

When and where does the respiratory diverticulum form?

A

4th week
Forms in the ventral wall of the foregut at the junction with the gut where the pharyngeal will form
(Lungs and bronchial tree derived from the foregut)

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

How do the respiratory primordium and the oesophagus separate?

A

Tracheoesophageal septum grows

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

How often do we get abnormal positions of the tracheoesophageal septum?

A

1 in 3000 live births

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

Describe the development of the stomach

A

Week 4 a slight dilation of the distal foregut occurs (stomach primordium)
Faster growth at the dorsal border creates the greater curve
Rotation - changes position of mesenteries

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

What structures are formed in the ventral mesentery?

A

Liver
Biliary system
Part of the pancreas (uncinate process and inferior head)

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

What structures are formed in the dorsal mesentery?

A

Superior head, neck, body and tail of the pancreas

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

Where is the lesser omentum?

A

Attaches the liver to the lesser curve of the stomach

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

What happens in the duodenum in the 5th-6th weeks?

A

Lumen is obliterated due to the rapid growth of the length and lining
Recanalised by the end of the embryonic period

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

Why does the duodenum become retroperitoneal?

A

Rotation of the stomach pushes the duodenum to the right and then against the posterior abdominal wall
(Secondary retroperitoneal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Which structures are secondary retroperitoneal?

A

Duodenum (except cap)

Pancreas

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

What is another name for the lesser sac?

A

Omental bursa

33
Q

What is the sign, during embryonic life, of atresia of the oesophagus?

A

Polyhydramnios
Prevents normal passage of amniotic fluid in the intestinal tract resulting in accumulation of excess fluid in the amniotic sac

34
Q

How is the spleen suspended?

A

Splenorenal ligament - connecting spleen to posterior abdominal wall in the area of the left kidney
Gastrosplenic ligament - connects the spleen to the stomach

35
Q

What forms the roof of the epiploic foramen of Winslow?

A

Free edge (lesser omentum)

36
Q

What is the gubernaculum?

A

Connects the developing testicle to the developing scrotum

Gets shorter and guides the testicle into place

37
Q

What is the primitive gut a derivative of?

A

Definitive yolk sac (during folding)

38
Q

What does the midgut make a loop around?

A

Superior mesenteric artery (axis)

39
Q

Why does the midgut need to herniate?

A

Midgut elongates enormously
Runs out of space because the abdominal cavity doesn’t grow at the same rate
Liver is also growing rapidly
Not enough space

40
Q

What attaches the midgut to the yolk sac?

A

Vitelline duct

41
Q

How are the cranial and caudal limbs defined?

A

Above and below where the SMA enters

42
Q

When does physiological herniation take place?

A

6th week

43
Q

Where do the intestines herniate?

A

Into the umbilical cord

44
Q

Describe midgut rotation

A

A series of 3 90 degree turns anticlockwise
Starts with cranial limb (above SMA)
1st turn occurs during herniation
2nd and 3rd turns occur on returning to the abdominal cavity

45
Q

Where do the limbs of the midgut come to lie?

A

Cranial limb = left side of SMA

Caudal limb = right side of SMA

46
Q

What happens during the second rotation?

A

Get the crossing of the 2 limbs

Caudal limb lies in front of the cranial limb

47
Q

What happens during the third rotation?

A

Cranial limb derivatives are pushed towards the left

Descent of caecal bud to create the ascending colon

48
Q

What are the cranial limb derivatives?

A

Distal duodenum
Jejunum
Proximal ileum

49
Q

What are the caudal limb derivatives?

A 
Distal ileum
Caecum 
Appendix 
Ascending colon
Proximal 2/3 transverse colon
50
Q

Describe incomplete rotation of the midgut

A

Midgut loop makes only one 90 rotation
Left sided colon
Limbs don’t twist on each other - cranial limbs not pushed back in first

51
Q

Describe reversed rotation

A

Midgut makes one 90 clockwise rotation
Less crossing
Caudal limb is not anterior to cranial limb
Transverse colon passes posterior to the duodenum

52
Q

When should the vitelline duct close?

A

After herniation resolves

53
Q

Name some consequences of a persistent vitelline duct

A

Vitelline cyst
Vitelline fistula
Meckel’s diverticulum

54
Q

Describe a Meckel’s diverticulum

A

Most common GI anomaly
Small diverticulum of small intestine where the vitelline duct was
May be free or attached to the abdominal wall
Rule of 2s: affects 2% population, 2 feet from ileocaecal, 2 inches long, under 2s, 2:1 male:female

55
Q

Which types of ectopic tissue can a Meckel’s diverticulum contain?

A

Gastric

Pancreatic

56
Q

Where in the GI tract does recanalisation have to occur?

A

In the oesophagus, bile duct and small intestine

57
Q

What is the difference between atresia and stenosis?

A 
Atresia = no lumen 
Stenosis = lumen narrowed
58
Q

Stenosis in the duodenum is most likely to be a result of …

A

Incomplete recanalisation

59
Q

What is pyloric stenosis?

A

Due to hypertrophy of the smooth muscle (circular) in the region of the pyloric sphincter
Not a recanalisation failure
Common abnormality in infants - projectile vomiting

60
Q

Where are atresia and stenoses most likely to occur?

A

Duodenum

61
Q

What divides the anal canal?

A

Pectinate line (superior and inferior)

62
Q

The urorectal septum divides the cloaca into the …

A

Urogenital sinus

Anorectal canal

63
Q

What is the proctodeum?

A

Anal pit
Small depression of ectodermal tissue
Comes up into the body to meet the endoderm tube

64
Q

What is the perineal body?

A

Pyramidal fibromuscular mass in the midline of the perineum

At the junction between the urogenital triangle and the anal triangle

65
Q

Describe the blood supply, innervation and lymphatic drainage of superior anal canal

A

Inferior mesenteric artery
S2,S3,S4 - pelvic PNS
Lymphatic drainage - internal iliac nodes

66
Q

Describe the blood supply, lymphatic drainage and innervation of inferior anal canal

A

Pudendal artery
S2, S3, S4 - pudendal nerve
Lymphatic drainage = superficial inguinal nodes

67
Q

Describe the epithelia difference between superior and inferior anal canal

A 
Superior = columnar 
Inferior = stratified squamous
68
Q

What is the sensation possible above the pectinate line?

A

Stretch

Poorly localised pain

69
Q

What sensations can be felt below the pectinate line?

A

Temperature
Touch
Pain (localised)

70
Q

Which type of innervation does the parietal peritoneum receive?

A

Somatic innervation

71
Q

What is an imperforate anus?

A

Failure of anal membrane to rupture

72
Q

What is anal/anorectal agenesis?

A

Failure of normal formation of anal canal

Absence of primordial tissue

73
Q

What are mesenteries retained by?

A 
Jejunum 
Ileum 
Appendix 
Transverse colon
Sigmoid colon
74
Q

Where do fused mesenteries occur?

A

Duodenum
Ascending and descending colon
Rectum

75
Q

What structures are formed from the dorsal mesentery?

A 
Greater omentum 
Gastrosplenic ligament 
Splenorenal ligament 
Mesocolon
Mesentery proper
76
Q

What does the ventral mesentery become?

A

Lesser omentum

Falciform ligament

77
Q

What is the innervation to the midgut?

A

PNS - vagus nerve

SNS - superior mesenteric ganglion and plexus

78
Q

What is the innervation to the hindgut?

A

PNS - pelvic (S2,3,4)

SNS - inferior mesenteric ganglion and plexus

Gastro-intestinal System (10 decks)

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