Brainscape's Knowledge GenomeTM

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


See full index

Microanatomy > GI Embryology > Flashcards

GI Embryology Flashcards

1
Q

Arteries and Gut Regions

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

Foregut

A

Esophagus

Stomach

Duodenum

Liver

Pancreas

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

Hindgut

A

Colon

Rectum

Anal Canal

Sigmoid

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

Midgut

A

Duodenum

Jejunum

Ileum

Colon

Cecum

Appendix

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

Pharyngeal Gut

A

Oral Cavity

Pharynx

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

Embryo Dev

A

Week 3 & 4 folding occurs into 3 disc layer

Endodermal lined gut tube connected to vitelline duct

Buccopharyngeal m. breaks down week 4 to form mouth= stomodeum

Cloacal m. ruptures in 7th week, creats opening for anus and urethra

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

Mesenteries

A

2x peritoneum that enclose organ & connect it to body wall

Peritoneaum simple squamous epith that secretes mucus and lines abdominal cavity

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

Dorsal Mesentary

A

extends from lower end of esophagus to cloacal region of hindgut.

Moditifed during dev to become:

Dorsal mesogastrium

mesoduodenum

proper

mesocolon

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

Ventral Mesentery

A

only in terminal esophagus, stomach & upper duodenum

Modified during development to become lesser omentum & falciform ligament.

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

Mucosa

A

Epithelial lining & glands (from endoderm)

Lamina propria

Muscularis mucosae

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

Splanchnic Mesoderm

A

Submucosa

Muscularis externa

Adventitia/serosa

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

Foregut Expanded

A

Esophagus- week 4 respiratory diverticulum is outgrowth from primitive gut tube.

Located caudal to primitive pharynx

Separated from dorsal part of foregut by tracheoesoph septum eventually.

Esophageal segment grows & eleongates during 2nd month.

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

Esophageal Atresia

A

Results from deviaton of tracheoesophageal septum in posterior direction associated w/ polyhydraminios

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

Short Esophagus

A

Failure of esophagus to elongate in proportion to dev of neck & thora.

Results in stomach being displaced cranially into thorax forming congenital hiatal hernia.

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

Stomach Dev

A

4TH week, dilation in foregut occurs

dorsal border grows fater than ventral border which yeild lesser & greater curvatures

Stomach develops in midline then rotates 90 CW then CCW

R & L vagus innervate post & ant walls

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

Omental Bursa

A

dorsal mesogastrim continues to expand during dev as 2x layered sac over both small intestines & transverse colon

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

Congenital Pyloric Stenosis

A

5x more common in males than in females

Hypertrophy of m. layer in pyloric region of stomach

After feeding stomach is distended= projectile vomiting!

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

Spleen Formation

A

Not foregut

Mesodermal origin- b/t layers of dorsal mesentery

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

Duodenum Formation

A

Week 4, distal foregut & proximal midgut join to form C shaped tube

Stomach rotation brings duodenum ultimately to lie on R side of abdominal cavity

Duodenum & pancrease head pressed dorsally against body wall.

R surface of dorsal mesoduodenum fuses with peritoneum.

Retroperitoneal position

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

Duodenal Formation 2

A

During 2nd month, duodenum epithelial proliferation, obliteration of lumen & recanalization

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

Duodenal Stenosis & Atresia

A

Stenosis partial occlusion of lumen due to incomplete recanalization of duodenum

Foreceful vomiting like in pyloric stenosis

Duodenal atresia complete closure of lumen & results in polyhydraminos

22
Q

Liver & Gallbladder Development

A

Glands of GT formed by complex interaction b/t endodermal outpocketings of primitive gut tube & surrounding mesenchyme (mesoderm)

*Use SHH & HOX

23
Q

Liver Bud

A

End of 3rd or beginning of 4th week, liver bud appears out of foregut

Caudal portion of liver bud differentiates into bile duct

overgrowth from bile duct gives rise to gallbladder & cystic duct.

As growth continues, liver bud extends into septum trasnversum

24
Q

Septum Transversum

A

Plate of splanchnic mesoderm lies b/t thoracic cavity & stalk of yolk sac. Appears on day 22

Ultimately becomes: central tendon of diaphragm & ventral mesentery

Hepatic cords (foregut endoderm) diff into hepatocytes & lining of biliary ducts

Umbilical & vitelline v.–> hepatic sinusoids

CT, hematopoietic tissue & Kupffer cells derived from mesoderm of septum transversum

25
Q

Bare A of Liver

A

Mesoderm on surface of liver fomrs visceral peritoneum of liver, except A where it lies in contact with diaphragm (bare A of liver)

26
Q

Functions of Developing Liver

A

Hematopoiesis- 5 to 6 week

Bile production- 12th week, bile drains down newly fomred bile duct & stored in intestines.

As bile released into intestines it gives meconium its characteristic green color

27
Q

Gallbladder & Extrahepatic Duct Development

A

Bile Duct- narrow channel b/t liver bud & foregut

Gllbladder & cystic duct- formed from outgrowth of bile duct

gallbladder also undergoes mitosis whereby lumen is obliterated

28
Q

Accessory Hepatic ducts & duplication of gallbladder

A

Also extrahepatic biliary atresia

Intrahepatic biliary atresia- from maternal infection

29
Q

Pancreas Formation

A

In 5th week

Two buds originating from endodermal lining of duodenum

Duodenum rotates 90 CW, the ventral bud carried dorsally (along with bile duct), eventually located posterior to dorsal bud.

2 buds fuse in 6th week

Dorsal bud- head, body & tail

Ventral bud- uncinate process

30
Q

Exocrine and Endocrine Pancreas

A

Exocrine- none

Endocrine-

Islets of Langerhan start to develop in 3rd month.

A cells diff first, followed by B cells or D cells

Not known when F cells are formed.

Glucagon first detected in fetal plasma by 15th week, insulin in 5th month.

31
Q

Ectopic Pancreatic Tissue

A

Can be found anywhere from distal esoph to tip of primary intestinal loop

Most freq in duodenum or mucosa of stomach

5% Meckel’s Diverticulum contains pancreatic tissue

32
Q

Annular Pancreas

A

2 portions of ventral bud rotates in opp direction & encircle the duodenum from both sides

33
Q

Midgut Dev

A

Midgut rapidly expands in 5th week resulting in fomraiton of U shaped loop

Same time as primary intestinal loop rotates 90 CCW around an axis formed by SMA

34
Q

Physiological Herniation

A

In 6th week all intestinal loops enter extraembryonic cavity in umbilical cord

Due to rapid growth of cephalic limb

Expansion of liver

35
Q

Retraction of Herniated Loops

A

In 10th week, intestine re enter abdominal cavity

As it returns it undergo a further 180 CCW rotation

Due to regression of 2nd kidnye sys, reduced growth of liver, expansion of abdominal cavity

During dev midgut undergoest 270 degree CCW rotation!

36
Q

Fixation of Intestines

A

Mesenteries of ascend & descend colon are fixed against peritoneum & later fuse, therefore they become retroperitoneal.

Transverse mesocolon fuses w/ post wall of greater omentum, maintainign its mobility

37
Q

Atresia or stenosis of gut

A

would cause considerable backup in gut leading to excessive GI distension & excessive vomiting in newborns.

Most commonly caused by vascular accidents

38
Q

Apple Peel Atresia

A

10% of bowel atresia, occurs in jejunum

39
Q

Recanalization

A
40
Q

Omphalocele

A

Failure of return of intestinal loop into body cavity after phys herniation 6-10 weeks

Associated w/ high rate mortality, sever cardiac & NTDs & chrom abnormalityes

41
Q

Gastroschisis

A

Herniation of abdominal contents through defect in abdominal wall directly into amniotic cavity.

Not covered by amnion & peritoneaum, occurs lateral to the umbiliucs

Not associated w chrom abnormalites or othere severe defects.

Excellent survival rates.

*ventral wall defect*

42
Q

Vitelline Duct Abnormalities

A

As intestines reenter abdomen, vitelline duct obliterated

Except:

Remnant of vitelline duct, may contain ectopic pancreatic or gastric tissue

43
Q

Abnormal Rotation

A
44
Q

Hindgut Dev

A

In embryonic period of cloaca is subdivided into anorectal canal (post) & urogenital sinus (ant)

Accomplished by means of urorectal septum.

45
Q

Anal Canal

A

Upper 2/3 formed from anorectal canal (hindgut)

Lower 1/3 formed from invagination of ectoderm

Junction is known as pectinate line.

At pectinate line epith undergoes a sudden transition from simple columnar to stratified squamous.

BV: cranial portion- sup rectal a.

Caudal portion- inf rectal a.

46
Q

Imperforate Anus

A

No anal opening, lack of recanalization of anal canal, failure of anal mem to break down .

47
Q

Rectoanal Atresia & fistula

A

ectopic positioning of anal opening, due to incomplete separation of anorectal canal from urogenital sinus

48
Q

Differentiation

A

Primite gut diff into diff organs depending on reciprocal inteaction b/t endoderm & mesoderm.

Mesoderm HOX dictates type of structure that will fomr

Endoderm SHH induces HOX expression in mesoderm

49
Q

Appendix

A
50
Q

Anal Canal

A

Upper 2/3= simple columnar

Lower 1/3= stratified squamous non keratinized

Anus- stratified sqamous keratinized of skin

51
Q

Anal Canal Sphincters

A

Internal Anal sphincter- thickened inner layer of muscularis externa

External anal sphincter- skeletal m.

Microanatomy (9 decks)

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