Embryology

Question 1

what gives rise to the epithelial lining and glands of the GI tract?

Answer 1

Endoderm

Question 2

what type of folding gives us the GI tract?

Answer 2

Cranio-caudal folding

Question 3

name the 3 gut regions

Answer 3

Foregut
Midgut
Hindgut

Question 4

what does the ssplanchnic mesoderm become?

Answer 4

Smooth muscle and connective tissue of the GI tract

Question 5

what forms the peritoneum?

Answer 5

Parietal - somatic mesoderm

Visceral - Splanchnic mesoderm

Question 6

what forms the mesenteries?

Answer 6

Dorsal and Ventral are BOTH from splanchnic mesoderm

Question 7

what is the function/structure of mesenteries

Answer 7

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

Question 8

What is the peritoneum?

Answer 8

The serous membrane lining of the abdominal cavity (parietal) and organs (visceral)

Question 9

what type of folding creates the mesenteries?

Answer 9

Lateral folding

Question 10

What gives rise to the lesser omentum?

Answer 10

Ventral mesogastrium

Question 11

what gives rise to the falciform ligament?

Answer 11

ventral mesogastrium

Question 12

THe ventral mesogastrium gives us what?

Answer 12

Lesser omentum and falciform ligament

Question 13

the greater omentum is created by what?

Answer 13

dorsal mesogastrium

Question 14

the mesentery proper gives us what structure?

Answer 14

small intestine

Question 15

what forms the enteric nervous system of the GI tract?

Answer 15

neural crest cells

Question 16

what artery supplies the pharynx?

Answer 16

Pharyngeal arch arteries

Question 17

the foregut is supplied by what?

Answer 17

celiac trunk

Question 18

THe midgut is supplied by which artery

Answer 18

superior mesenteric artery (SMA)

Question 19

the hindgut is supplied by what?

Answer 19

inferior mesenteric artery (IMA)

Question 20

name the foregut derivatives

Answer 20

1) larynx
2) lower respiratory system
3) esophagus
4) stomach
5) proximal half of duodenum
6) associated organs (liver, gall bladder, pancreas)

Question 21

when does the respiratory diverticulum appear?

Answer 21

week 4

Question 22

where does the tracheoesophageal septum grow in from?

Answer 22

the lateral sides of the foregut. divide it into lower resp tract and esophagus

Question 23

what is Stenosis?

Answer 23

abnormal narrowing of a lumen/orafice

Question 24

define atresia

Answer 24

a body lumen or orifice is abnormally closed or absent

Question 25

what is a fistula?

Answer 25

abnormal passageway between two organs/vessels

Question 26

what causes the formation of the greater curvature in the stomach?

Answer 26

the dorsal side of the stomach expands faster, starting at week 4

Question 27

which vagus nerve supplies the dorsal stomach? the ventral?

Answer 27

Dorsal - right | Ventral - Left

Question 28

what is the Omental bursa?

Answer 28

The lesser sac of the peritoneum

Question 29

what causes the enlargement of the Omental bursa?

Answer 29

the rotation of the stomach carries the Dorsal Mesogastrium to the left

Question 30

where is the Omental Bursa located?

Answer 30

posterior to the stomach, with superior and inferior recesses

Question 31

what forms the greater omentum?

Answer 31

the dorsal mesogastrium flapping over the small intestines

Question 32

what artery supplies the duodenum

Answer 32

the celiac trunk - first half | SMA - second half

Question 33

where does the hepatic diverticulum emerge?

Answer 33

ventrally from endoderm of distal foregut- gives liver, gall bladder and bile duct

Question 34

the ventral and distal buds of the endodermal foregut form what?

Answer 34

Pancreas

Question 35

what does the ventral bud of the pancreas become?

Answer 35

uncinate process + inferior portion of head

Question 36

what makes up the main pancreatic duct?

Answer 36

distal portion of dorsal bud duct | ventral bud duct

Question 37

the accessory pancreatic duct emerges from what?

Answer 37

proximal dorsal bud duct

Question 38

what are the midgut derivatives?

Answer 38

``` distal half of duodenum jejunum ileum cecum & appendix ascending colon proximal 2/3 of transverse colon ```

Question 39

the Vitelline duct does what?

Answer 39

connects midgut to yolk sac

Question 40

what is congenital Omphalocele?

Answer 40

persisting umbilical herniation. Vicera covered by amnion & WITHIN proximal umbilical cord

Question 41

Gastrochisis

Answer 41

hernia through body wall and does not involve umbilical cord. Exposure to external amniotic fluid can damage viscera

Question 42

when does the midgut make its first 90 degree rotation?

Answer 42

week 6

Question 43

what is the 2nd midgut rotation? when does it occur?

Answer 43

180 degree counter-clockwise rotation that brings intestines to their normal position. during week TEN

Question 44

are the ascending and descending colon within the peritoneum?

Answer 44

NO. they become secondarily retroperitoneal

Question 45

which structures are intraperitoneal?

Answer 45

A) proximal duodenum B) Jejunum, Ileum C) transverse colon D) sigmoid colon

Question 46

what structures are retroperitoneal?

Answer 46

``` A) distal duodenum B) pancreas C) ascending colon D) descending colon E) kidneys ```

Question 47

Volvulus

Answer 47

abnormal rotation causes intestinal loop twist around mesenteric attachment. leads to bowel obstruction

Question 48

recanalization of midgut loop

Answer 48

when Intestines are temp occluded at week 6 because of endodermal growth

Question 49

what is Meckel's (ileal) diverticulum?

Answer 49

a remnant of the Vitelline duct. persists as finger-like out pouching of the ileum. may cause ulcers and bleeding

Question 50

what does the hindgut form?

Answer 50

``` distal 1/3 of transverse colon decending colon sigmoid colon rectum superior part of anal canal ```

Question 51

what does the Urorectal septum do?

Answer 51

divides cloaca into urogenital sinus and the anorectal canal

Question 52

what is Hirschsprung's disease? (ananglionic megacolon

Answer 52

ananglionic portion of bowel constricts and decends. Leads to severe constipation