EX2 Embryology Flashcards Preview

SP14 Anatomy > EX2 Embryology > Flashcards

Flashcards in EX2 Embryology Deck (78)
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1
Q

Which germ layer forms the epithelial lining and glands of the GI tract

A

endoderm

2
Q

The endoderm that dorms the innermost lining of the gut tube is derived from where

A

the dorsal portion of the yolk sac

3
Q

This duct connects the midgut and the yolk sac

A

vitelline duct

4
Q

This membrane ruptures at week 4 and provides a continuity between the oral cavity and the foregut

A

oropharyngeal membrane; allows for swallowing of amniotic fluid

5
Q

This membrane ruptures at week 7 and allow for urination and defication

A

cloacal membrane

6
Q

Which germ layer forms the smooth muscles and the connective tissues of the GI tract

A

splanchnic mesoderm

7
Q

This is the serous membrane lining the abdominal cavity and organs

A

peritoneum

8
Q

This type of peritoneum lines the abdominal cavity

A

parietal peritoneum

9
Q

This type of peritoneum lines the organs

A

visceral peritoneum

10
Q

This is a double layer of peritoneum that suspends an organ from the body wall

A

mesentery

11
Q

True or False

Mesentery can contain CT, blood vessels, lymphatics, and/or nerves

A

True

12
Q

The peritoneum and mesentery are derived from what germ layer

A

sphanchnic mesoderm

13
Q

At what level of the GI tract does the ventral mesentery exist

A

foregut; it is resorbed inferior to it

14
Q

The ventral mesogastrium is divided into which two segments due to the outgrowth of which organ

A

falciform ligament
lesser omentum
liver

15
Q

The lesser omentum (derived from what?) splits into what ligaments

A

LO is derived from ventral mesogastrium
hepatogastric ligament
hepatouodenal ligament

16
Q

The dorsal mesogastrium forms what

A

greater omentum

17
Q

The dorsal mesentery forms what four structures

A

dorsal mesogastrium
mesoduodenum
mesentery proper
mesocolon

18
Q

The neural crest cells migrate into the walls of GI tract to form what

A

enteric nervous system (intrinsic nervous system)

19
Q

This section of the GI tract is from the mouth to the first 1/2 of the duodenum

A

foregut

20
Q

This section of the GI tract is from the second 1/2 of the duodenum to the first 2/3 of the transverse colon

A

midgut

21
Q

This section of the GI tract is from the last 1/3 of the transverse colon to the anus

A

hindgut

22
Q

The main blood supply to the GI tract is what

A

abdominal aorta (and its 3 branches)

23
Q

The blood supply to the foregut is supplied via which artery

A

celiac trunk

24
Q

The blood supply to the midgut is supplied via which artery

A

superior mesenteric artery

25
Q

The blood supply to the hindgut is supplied via which artery

A

inferior mesenteric artery

26
Q

The blood supply to the pharynx is supplied via which artery

A

pharyngeal arch

27
Q

What six main structures are a part of the foregut

A
pharynx
lower respiratory system
esophagus
stomach
proximal 1/2 of duodenum
associated organs (pancreas, liver, gall bladder, etc.)
28
Q

The foregut/midgut divide is typical where

A

after the entrance of the pancreatic and bile ducts in the duodenum

29
Q

The esophagus develops as the portion of the foregut immediately (cranial/caudal) to the pharynx

A

caudal

30
Q

This appears on the ventral side of the foregut and will become the trachea, respiratory tree, and lungs, during what week

A

respiratory diverticulum

week 4

31
Q

This appears from the lateral sides of the foregut, diving the foregut into the lower respiratory tract and esophagus

A

tracheoesophageal septum

32
Q

This is the abnormal narrowing of a lumen/orifice (tubular organ or structure)

A

stenosis

33
Q

This is a condition in which a body lumen or orifice is abnormally closed or absent

A

atresia

34
Q

Causes of stenosis/atresia can include what four things

A

failure to reanalyze following a temporary epithelial plug
adequate blood supply fails to develop
accidents that compromise blood flow
mechanical obstruction

35
Q

This is an abnormal passageway between two organs/vessels or between an organ and the external environment

A

fistula

36
Q

Esophageal atresia and trachesophageal fistula can lead to what

A

risk of polyhydraminos (too much amniotic fluid)

37
Q

During week 4, a portion of the foregut begins to dilate uniformly, this becomes what?

A

the stomach

38
Q

As the stomach enlarges, its dorsal side expands faster than the other sides and it will be come the what? and the ventral side becomes this?

A

greater curvature

lesser curvature

39
Q

The stomach will undergo a rotation that is which direction (this is caused by uneven distribution of weight)

A

90° clockwise rotation

40
Q

During the stomachs 90° clockwise rotation, the ventral side ends up on what side and is supplied by what nerve

A

right side supplied via the left vagus

the dorsal side (left) is supplied via the right vagus

41
Q

This is caused by the circular smooth muscles constricting the pyloric lumen preventing passage of the stomach contents to the SI

A

hypertrophic pyloric stenosis

42
Q

As the stomach rotates, this is carried to the left

A

dorsal mesogastrium

43
Q

As the dorsal mesogastrium is carried to the left by the stomach, it enlarges this into a sizable recess between the stomach and posterior abdominal wall

A

omental bursa (lesser sac of peritoneum)

44
Q

This organ forms between two leaves of dorsal mesogastrium during week 5

A

spleen

45
Q

This forms as a C-shaped loop distal to the stomach; supplied by both the celiac trunk and SMAl where the pancreatic and common bile ducts empty

A

duodenum

46
Q

As the stomach rotates CW, it drags the distal duodenum and pancreas to where they become this; their dorsal mesenteries are lost

A

retroperitoneal (secondarily)

47
Q

This is the failure of the lumen to recanalize in the duodenum by week 8; vomit will either contain or not contain bile depending on where the obstruction is located

A

duodenal stenosis and atresia

48
Q

This emerges ventrally from endoderm of the distal foregut and grows superiorly toward the septum transvedsum (diaphragm) and gives rise to what three things

A

hepatic diverticulum

liver, gall bladder, and bile ducts

49
Q

This organ emerges from distal foregut as two endodermal buds (ventral and dorsal)

A

pancreas

50
Q

True or False

The ventral bud of the pancreas does not fuse with the dorsal bud

A

False; as the duodenum rotates, the ventral bud swings and fuses with the dorsal bud

51
Q

The ventral bud go the pancreas becomes what two things

A

uncinate process

inferior portion of head of pancreas

52
Q

The main pancreatic duct forms from which two ducts buds

A

distal portion of dorsal bud duct and ventral bud duct

53
Q

The accessory pancreatic duct forms from what duct bud

A

proximal dorsal bud duct

54
Q

This is caused when the ventral bud of the pancreas develops into two portions and they fail to fuse resulting in one wrapping around the duodenum then fusing

A

annular pancreas

55
Q

The midgut is composed of these six main structures

A
distal 1/2 of duodenum
jejunum
ileum
cecum and appendix
ascending colon
proximal 2/3 of transverse colon
56
Q

The cranial limb of the midgut U-shaped loop forms which three structures

A

distal duodenum
jejunum
proximal ileum

57
Q

The caudal limb of the midgut U-shaped loop forms which four structures

A

distal ileum
cecum and appendix
ascending colon
proximal 2/3 of transverse colon

58
Q

This is when there is insufficient room in the abdominal cavity and it leads to temporary herniation of midgut loop into the proximal umbilical cord

A

physiological umbilical herniation

59
Q

This is a persisting umbilical herniation; viscera covered by amnion and within proximal umbilical cord

A

congenital omphalocoele

60
Q

This is when a hernia is through the body wall and does not involve the umbilical cord; exposure to amniotic fluid can damage the viscera

A

gastrochisis

61
Q

During week 6 the midgut undergoes what type of rotation

A

90° counterclockwise

SMA is axis of rotation

62
Q

During week 10 the midgut undergoes a second rotation of which is what?

A

180° counterclockwise which brings the intestines into normal position (270° total rotation)

63
Q

True or False

The ascending and descending colon are intraperitoneal

A

False; they become secondarily retroperitoneal; their dorsal mesenteries are lost after fusion with parietal peritoneum of posterior abdominal wall

64
Q

These five structures are considered intraperitoneal

A
proximal duodenum
jejunum
ileum
transverse colon
sigmoid colon
65
Q

These five structures are considered retropeitoneal

A
distal duodenum
pancreas
ascending colon
descending colon
kidneys (form retroperitoneal)
66
Q

This is the result if the caudal limb returns first from the midgut loop

A

left-sided colon

67
Q

If there is an 180° clockwise (instead of counterclockwise) it results in a net 90° clockwise rotation which causes this to happen

A

the duodenum is now ventral to the TVC (doesn’t become retroperitoneal)

68
Q

This is caused by abnormal rotation which may cause intestinal loop twist around mesenteric attachment site; can result in bowel obstruction/compromised blood flow leading to stenosis, necrosis, etc.

A

volvulus

69
Q

The recanalization of the midgut loop occurs during what week

A

week 8

the epithelial cells occlude at week 6 and dissolve at week 8

70
Q

This is a remnant of the vitelline duct persisting as a finger-like out-pouching of the ileum about 40-60cm from the ileocecal junction; may contain tissue/gastric mucosa that secretes acid; causing ulcers/bleeding

A

Meckel’s (ileal) diverticulum

71
Q

What are the three variations of a persistent vitelline duct

A

vitelline fistula
vitelline cyst
vitelline ligament

72
Q

The hindgut is composed of these five structures

A
distal 1/3 transverse coon
descening colon
sigmoid colon
rectum
superior portion of anal canal
73
Q

These two structures are derived from the posterior portion of the cloaca after it is partitioned by the urorectal septum

A

rectum

superior portion of anal canal

74
Q

This grows inferiorly toward the cloacal membrane dividing it into urogenital and anal membranes

A

urorectal septum

75
Q

The urorectal septum partitions the cloaca into what two things

A
urogenital sinus (ventrally)
anorectal cana (dorsally)
76
Q

What two arteries supply the anal canal

A

superior rectal artery supplies the portion of the anal canal from the hindgut
inferior rectal artery supplies the portion distal to that

77
Q

This form if the urorectal septum fails to completely separate the hindgut from the urogenital sinus or if the cloaca is too small

A

hindgut fistula (anal canal not connected to anal pit)

78
Q

This disease is a result of when neural crest cells fail to migrate to form the enteric nervous system; causing constriction of the aganglionic portion and bowel distending proximal to the constriction

A

Hirschspring’s disease (aganglionic megacolon)