EX2 Embryology Flashcards Preview

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Flashcards in EX2 Embryology Deck (78):
1

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

endoderm

2

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

the dorsal portion of the yolk sac

3

This duct connects the midgut and the yolk sac

vitelline duct

4

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

oropharyngeal membrane; allows for swallowing of amniotic fluid

5

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

cloacal membrane

6

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

splanchnic mesoderm

7

This is the serous membrane lining the abdominal cavity and organs

peritoneum

8

This type of peritoneum lines the abdominal cavity

parietal peritoneum

9

This type of peritoneum lines the organs

visceral peritoneum

10

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

mesentery

11

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

True

12

The peritoneum and mesentery are derived from what germ layer

sphanchnic mesoderm

13

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

foregut; it is resorbed inferior to it

14

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

falciform ligament
lesser omentum
liver

15

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

LO is derived from ventral mesogastrium
hepatogastric ligament
hepatouodenal ligament

16

The dorsal mesogastrium forms what

greater omentum

17

The dorsal mesentery forms what four structures

dorsal mesogastrium
mesoduodenum
mesentery proper
mesocolon

18

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

enteric nervous system (intrinsic nervous system)

19

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

foregut

20

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

midgut

21

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

hindgut

22

The main blood supply to the GI tract is what

abdominal aorta (and its 3 branches)

23

The blood supply to the foregut is supplied via which artery

celiac trunk

24

The blood supply to the midgut is supplied via which artery

superior mesenteric artery

25

The blood supply to the hindgut is supplied via which artery

inferior mesenteric artery

26

The blood supply to the pharynx is supplied via which artery

pharyngeal arch

27

What six main structures are a part of the foregut

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

28

The foregut/midgut divide is typical where

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

29

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

caudal

30

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

respiratory diverticulum
week 4

31

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

tracheoesophageal septum

32

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

stenosis

33

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

atresia

34

Causes of stenosis/atresia can include what four things

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

35

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

fistula

36

Esophageal atresia and trachesophageal fistula can lead to what

risk of polyhydraminos (too much amniotic fluid)

37

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

the stomach

38

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?

greater curvature
lesser curvature

39

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

90° clockwise rotation

40

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

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

41

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

hypertrophic pyloric stenosis

42

As the stomach rotates, this is carried to the left

dorsal mesogastrium

43

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

omental bursa (lesser sac of peritoneum)

44

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

spleen

45

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

duodenum

46

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

retroperitoneal (secondarily)

47

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

duodenal stenosis and atresia

48

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

hepatic diverticulum
liver, gall bladder, and bile ducts

49

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

pancreas

50

True or False
The ventral bud of the pancreas does not fuse with the dorsal bud

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

51

The ventral bud go the pancreas becomes what two things

uncinate process
inferior portion of head of pancreas

52

The main pancreatic duct forms from which two ducts buds

distal portion of dorsal bud duct and ventral bud duct

53

The accessory pancreatic duct forms from what duct bud

proximal dorsal bud duct

54

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

annular pancreas

55

The midgut is composed of these six main structures

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

56

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

distal duodenum
jejunum
proximal ileum

57

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

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

58

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

physiological umbilical herniation

59

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

congenital omphalocoele

60

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

gastrochisis

61

During week 6 the midgut undergoes what type of rotation

90° counterclockwise
SMA is axis of rotation

62

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

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

63

True or False
The ascending and descending colon are intraperitoneal

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

64

These five structures are considered intraperitoneal

proximal duodenum
jejunum
ileum
transverse colon
sigmoid colon

65

These five structures are considered retropeitoneal

distal duodenum
pancreas
ascending colon
descending colon
kidneys (form retroperitoneal)

66

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

left-sided colon

67

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

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

68

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.

volvulus

69

The recanalization of the midgut loop occurs during what week

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

70

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

Meckel's (ileal) diverticulum

71

What are the three variations of a persistent vitelline duct

vitelline fistula
vitelline cyst
vitelline ligament

72

The hindgut is composed of these five structures

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

73

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

rectum
superior portion of anal canal

74

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

urorectal septum

75

The urorectal septum partitions the cloaca into what two things

urogenital sinus (ventrally)
anorectal cana (dorsally)

76

What two arteries supply the anal canal

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

77

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

hindgut fistula (anal canal not connected to anal pit)

78

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

Hirschspring's disease (aganglionic megacolon)