3-Development Of Gi Tract

Front 1

What helps in forming the primitive gut tube?

Back 1

longitudinal and lateral folding

Front 2

What are the three parts of the developing GI? What do members of each part share?

Back 2

foregut, midgut, hindgut
similar vascular supply, innervation, and lymph vessels, similar referred pain

Front 3

What is the consequence of lateral folding?

Back 3

endodermal ling of the upper part of the Yolk Sac is incorporated into the embryo and forms the lining of the primitive gut

Front 4

The cephalic part of the gut is called what? caudal?

Back 4

foregut
hindgut

Front 5

What attaches the primitive gut to the body wall? Is it fixed of suspended?

Back 5

dorsal mesentery
suspended

Front 6

As folding of the gut occurs what happens to the splanchnic mesoderm? Why is this important?

Back 6

right and left sides of splanchnic mesoderm fold toward each other
these lateral folds merge in the midline and form dorsal and ventral mesentery

Front 7

What differs between dorsal and ventral mesentery?

Back 7

the ventral mesentery only forms to the foregut segment
the dorsal mesentery goes to all parts

Front 8

Why are mesenteries referred to as being 'two-layered' thick of 'bilayered'?

Back 8

b/c they have origins from both the right and left splanchnopleure

Front 9

How are nevers and vessels able to reach the developing GI?

Back 9

mesenteries

Front 10

What are the derivatives of the primitive dorsal mesentery? Where does each go to?

Back 10

dorsal mesogastnum-to stomach
the mesentery-small intestine (jejunum & ileum)
transverse mesocolon-transverse colon
sigmoid mesocoln-sigmoid colon

Front 11

Anatomically and clinically, what are mesenteries known as?

Back 11

bilayered visceral peritoneum or visceral peritoneal folds

Front 12

What is the layer of splanchnopleure enclosing an organ called?

Back 12

visceral peritoneal covering

Front 13

What is the mesoderm lining the body wall called? What is the wall called?

Back 13

parietal peritoneum
peritoneal cavity

Front 14

What are the EARLY derivatives of the foregut?

Back 14

stomach, liver and gall bladder

Front 15

What does the liver form between?

Back 15

the two 'layers' of the ventral mesentery

Front 16

What artery supplies the foregut? midgut? hingut?

Back 16

F-celiac
M-Superior mesenteric A
H-Inferior mesenteric A

Front 17

The stomach is initally attached to the ventral wall by the ventral mesentery (as well as to the dorsal wall by dorsal mesentery). What is this ventral mesentery later called?

Back 17

lesser omentum

Front 18

Which side of the stomach is faster growing? What does this create?

Back 18

dorsal surface, creates Greater Curvature

Front 19

Why is a long mesenteric fold hanging freely from the stomach in some adults?

Back 19

the original dorsal mesogastrium grows much more than its adjacent dorsal mesentery

Front 20

Why does the Lesser Curvature form? What side is this located on?

Back 20

the ventral surface does not match the growth pace of the dorsal surface

Front 21

Which way does the stomach rotate? What does this do to the original dorsal and ventral sides?

Back 21

rotates 90 to the right
dorsal swept to left, ventral moves toward right

Front 22

What creates a bulge near the junction of the stomach and esophagus? What is this called?

Back 22

differential growth in the cranial end of the stomach tube
called the fundus

Front 23

What is the notch that is between the fundus and the esophagus?

Back 23

cardiac incisure

Front 24

What is the name of the region of the stomach located distally?

Back 24

pyloric region

Front 25

What does the ventral mesentery become partitioned by?

Back 25

liver

Front 26

What is the proximal part of the ventral mesentery between? What is this called?

Back 26

between stomach and liver
called lesser omentum

Front 27

Which way does the lesser omentum move when the stomach rotates?

Back 27

right

Front 28

What are the two parts of the lesser omentum?

Back 28

hepatogastric ligament
hepatoduodenal ligament

Front 29

Which ligament of the lesser omentum is more inferior? Which is smaller?

Back 29

hepatoduodenal ligament for both

Front 30

What is the distal part of the ventral mesentery between? What is it called?

Back 30

between liver and ventral body wall
falciform ligament

Front 31

What is the narrowing of the pyloric of the stomach called?

Back 31

hypertrophic pyloric stenosis

Front 32

What is the cause of hypertrophic pyloric stenosis?

Back 32

thickening of the circular muscle in the wall of the stomach

Front 33

What creates the 'blind pouch' posterior to the stomach? What is this called?

Back 33

rotation of the stomach dragging along its attached mesenteries
omental bursa

Front 34

What does the omental bursa come off of?

Back 34

peritoneal cavity

Front 35

What is another name for the omental bursa?

Back 35

lesser peritoneal sac

Front 36

What binds the lesser peritoneal sac?

Back 36

lesser omentum, stomach, dorsal mesogastrium and posterior body wall

Front 37

What is the entry point to the lesser peritoneal sac called? Where is this opening located?

Back 37

omental foramen
caudal to the inferior edge of the lesser omentum

Front 38

What is the clinical importance of the lesser peritoneal sac?

Back 38

it's an important entry point for the spread of pathology into the bursa

Front 39

What is the spleen derived from?

Back 39

mesoderm (not endoderm)

Front 40

The spleen begins as mesenchymal condensations within what?

Back 40

dorsal mesogastrium

Front 41

What is the result of the 'clumps' that make the spleen?

Back 41

a notched border on the spleen is seen in adults

Front 42

What does the spleen deveop between?

Back 42

R&L layers of the dorsal mesentery

Front 43

Which side of the body is the spleen on? What causes it to move in this direction?

Back 43

left
due to repositiong of the mesentery w/ the rotation of the stomach

Front 44

What does the spleen subdivide? What are the divisions named?

Back 44

mesentery
splenorenal (lienorenal) ligament and gastrosplenic (gastrolienal) ligament

Front 45

What forms the left boundary of the lesser peritoneal sac?

Back 45

splenorenal and gastrosplenic ligaments

Front 46

What forms the hepatic diverticulum? What part of the gut does this bud from?

Back 46

hepatic plate of tissue from duodenal/gastric area
foregut

Front 47

What keeps the hepatic diverticulum connected to the foregut?

Back 47

hepatic duct (stalk)

Front 48

What do the liver cords eventrually become?

Back 48

hepatocytes/parenchyma

Front 49

What do the spaces in the mesodermal core between the liver cords become?

Back 49

hepatic sinusoids

Front 50

What bud does the hepatic duct give rise to? What will this go on to form?

Back 50

cystic diverticulum
will develop gall bladder

Front 51

What will the proximal hepatic duct be called?

Back 51

common bile duct

Front 52

Where does the common bile duct empty its contents?

Back 52

duodenum

Front 53

What is the biliary duct system composed of?

Back 53

cystic duct attached to hepatic duct, the proximal part of hepatic duct is called the common bile duct

Front 54

What causes the liver to be in the RUQ?

Back 54

the liver grows rapidly, neighboring organs grow slower and stomach rotates

Front 55

How much weight does the liver account for at birth?

Back 55

10%

Front 56

What is the ventral mesentery partitioned by?

Back 56

liver

Front 57

What is the proximal part of the ventral mesentery called? distal?

Back 57

lesser omentum
falciform ligament

Front 58

Which region of the gut is the ventral mesentery found?

Back 58

foregut

Front 59

What is the remnant of the umbilical vein called?

Back 59

ligamentum teres hepatis

Front 60

Where does the umbilical vein run?

Back 60

along the inferior free margin of the ventral mesentery

Front 61

What makes up the portal triad?

Back 61

hepatic artery & (portal) vein, and bile duct

Front 62

What ist he reflection of peritoneum from the liver's surface tot he inferior surface of the diaphragm called?

Back 62

coronary ligament

Front 63

Does the bare area of the liver have a peritoneal or non-peritoneal surface?

Back 63

non-peritoneal

Front 64

What is the duodenum derived from?

Back 64

distal end of foregut and proximal end of midgut

Front 65

What is the vascular supply of the duodenum?

Back 65

celiac trunk and SMA

Front 66

What are the four parts of the duodenum?

Back 66

1-duodenal bulb (cap)
2-descending part
3-horizontal
4-ascending

Front 67

At what part of the duodenum is the entry point for the duct system from the liver

Back 67

descending segment

Front 68

What is reduction in the size of the duodenum w/ abnormal narrowing of the gut segment? At what part of the duodenum does this normally occur?

Back 68

duodenal stenosis
3 or 4

Front 69

What is canalization? How does this relate to duodenal stenosis?

Back 69

normally, duodenal lumen fills w/ cells, but lumen is re-opened by the process of canalization, in duodenal stenosis there is incomplete recanalization

Front 70

What is duodenal atresia?

Back 70

abnormal degeneration of the duodenum

Front 71

Which type of duodenal anomality has bile in the vomit? Duodenal atresia or dudenal stenosis?

Back 71

both do

Front 72

What is the ventral bud of the pancreas associated with?

Back 72

hepatic duct

Front 73

What will the ventral bud of the pancreas become? dorsal bud?

Back 73

uncinate process (fishhook shaped)
neck, body and tail

Front 74

What does the duct of the ventral bud become?

Back 74

main pancreatic duct

Front 75

The main pancreatic duct and bile duct combine to form what?

Back 75

hepatopancreatic duct

Front 76

The hepatopancreatic duct expands to form what?

Back 76

ampulla of Vater

Front 77

What part of the duodenum does the ampulla of vater enter?

Back 77

2nd part

Front 78

What is the major duodenal pailla?

Back 78

the raised mucosal tissue present on the duodenum where the hepatopancreatic duct enters

Front 79

What is the old attachment of the duct from the original dorsal bud of the pancreas called?

Back 79

minor papilla

Front 80

What does the tail of the pancreas grow between?

Back 80

dorsal mesogastrium , toward the spleen
eventually within the splenorenal ligament

Front 81

Which type of pancreatic cells produce digestive enzymes? What do these cells differentiate from?

Back 81

exocrine cells, from pancreatic bud endoderm

Front 82

Which type of pancreatic cells are in the islets of Langerhans? What are 2 things they have been suggested to come from?

Back 82

endocrine cells, from neural crest cells or gut endoderm

Front 83

What is Annular Pancreas? What can this cause?

Back 83

bilobed ventral pancreatic bud
the two ends migrate around the duodenum causing strangulation (duodenal atresia or stenosis)

Front 84

What part of the small intestine is midgut derived?

Back 84

distal half of duodenum, all of jejunum and illeum

Front 85

What part of the large intestine is midgut derived?

Back 85

cecum, appendix, ascending colon and proximal 2/3 of transverse colon

Front 86

What are the three phases of midgut development?

Back 86

elongation & herniation
return of the loop to abdominal cavity
fixation of mesenteries

Front 87

Which phase of midgut development is responsible for forming the primary intestinal loop?

Back 87

elongation & herniation (phase I)

Front 88

What is the apex of the primary intestinal loop attached to?

Back 88

yolk sac

Front 89

The proximal limb of the primary intestinal loop will form what?

Back 89

distal half of the duodenum and the jejunum and ileum

Front 90

The distal limb of the primary intestinal loop will form what?

Back 90

cecum, ascending colon and 2/3 of transverse colon

Front 91

Which limb (proximal/distal) grows faster for the primary intestinal loop?

Back 91

proximal

Front 92

During phase 1 which way does the midgut loop rotate? What ist he axis that defines this rotation?

Back 92

to the right
SMA

Front 93

Where do you find blood vessels leading to and draining the gut?

Back 93

within the mesentery

Front 94

Where is the transverse colon located with respect to the duodenum?

Back 94

anterior and transverse to

Front 95

What is a subhepatic cecum? Where is the cecum normally located?

Back 95

when the cecum fails to descend to the RLQ and remains just under the liver
Normally in RLQ

Front 96

What is the SMA between?

Back 96

posterior to transverse colon and anterior to 3rd part of duodenum

Front 97

Which quadrant is the jejunum located? ileum?

Back 97

jejunum-LUQ
ileum-RLQ

Front 98

What forms a diverticulum or bud off the cecum?

Back 98

appendix

Front 99

Which limb of the primary intestinal loop forms coils? Which limb retruns first?

Back 99

proximal for both

Front 100

What is malrotation of the gut? What is there an increased risk of?

Back 100

gut didn't rotate normally
chance of necrosis

Front 101

Which mesentery is fixed during fixation of the mesenteries?

Back 101

dorsal

Front 102

What causes the mesenteries to be 2-layered?

Back 102

during embryonic folding the right and left side layers of splanchnic mesothelium come together

Front 103

Which layer of the mesentery is swept toward the body wall? Is this layer visceral or peritoneal peritoneum?

Back 103

right side
visceral

Front 104

The visceral and peritoneal peritoneums interact to become what?

Back 104

fusion fascia

Front 105

What is retroperitoneal?

Back 105

when an organ is covered on 3 sides or less by visceral peritoneum

Front 106

What is a secondarily retroperitoneal organ?

Back 106

when an organ starts as intraperitoneal and becomes retroperitoneal

Front 107

Name two organs that develop from the start retroperitoneal?

Back 107

rectum and kidneys

Front 108

What provides a plane for surgical dissection that would avoid invasion of the peritoneal cavity?

Back 108

fusion fascia

Front 109

Is the pancreas retroperitoneal or intraperitoneal? duodenum?

Back 109

both become retroperitoneal

Front 110

Which layer of the mesentery (right/left) fuses w/ the peritoneum of the dorsal body wall and fuses the pancreas? Which part of the pancreas is fused?

Back 110

left layer
tail of the pancreas

Front 111

What replaces the fused peritoneal lyers of the pancreas posteriorly?

Back 111

fusion fascia

Front 112

When the right layer of the dorsal mesentery fuses with the parietal peritoneum on the dorsal wall which part of the pancreas is fused? Which other organ is at this level?

Back 112

head of pancreas
duodenum

Front 113

What is the definitive mesentery to the jejunum and ileum called? Where does it attach in the adult?

Back 113

The Mesentery
diagonally along the posterior abdominal wall from the 4th part of duodenum down to R sacroiliac joint

Front 114

What is the attachment line of The Mesentery called?

Back 114

root

Front 115

The SMA travels in the root of the mesentery and between its 2 layers where it arrives at what?

Back 115

mesenteric surface (line of attachment) of the jejunum and ileum

Front 116

What forms the paracolic gutters? What is their significance?

Back 116

fixation causes the depressions in the peritoneum on each side of the ascending and descending colons
the gutters act as conduits for movement of fluid through the peritoneal cavity

Front 117

What does the greater omentum fuse to?

Back 117

itself and part of the mesentery to the transverse colon

Front 118

The resultant mesentery that attaches to the stomach and to the transverse colon is also called what?

Back 118

gastrocolic ligament

Front 119

What creates the transverse mesocolon?

Back 119

fusion of the transverse colon's mesentery proximally to peritoneum overlying the pancreas and duodenum and tot he posterior aspect of the greater omentum

Front 120

Is the transverse colon retroperitoneal or intraperitoneal?

Back 120

intraperitoneal

Front 121

What attaches the transverse colon to the posterior wall?

Back 121

hepatic flexure and splenic flexure

Front 122

What are the derivatives of the hindgut?

Back 122

distal 1/3 of transverse colon, descending and sigmoid colons, rectum and superior part of anal canal

Front 123

What is the non-fixed, mobile mesentery of the sigmoid colon called? Is the sigmoid retroperitoneal or intraperitoneal?

Back 123

sigmoid mesocolon
intraperitoneal

Front 124

Discuss the peritoneum of the rectum?

Back 124

upper 1/3 is covered on 3 sides
middle 1/3 only has peritoneum anteriorly
distal 1/3 has no peritoneum
=retroperitoneal

Front 125

What is the vascularture of the large intestine?

Back 125

SMA and IMA

Front 126

What are the 3 folds of the mesoderm? What do they partition?

Back 126

cloaca
Tourneux fold
Rathke folds
separate distal hindgut, or urogenital sinus from the anorectal canal

Front 127

What is the dilated junction of the allantois and hindgut?

Back 127

cloaca

Front 128

What is the cranial-to-caudal migrating mesoderm? This fold will join inferiorly with which other fold?

Back 128

Tourneux fold
Rathke folds

Front 129

What are Rathke folds?

Back 129

infolding mesoderm from the left and right sides

Front 130

What are the 3 folds of the mesoderm collectively called?

Back 130

urorectal septum

Front 131

The fusion of uorectal septum with the cloacal membrane divides what two things?

Back 131

urogenital membrane and anal membrane

Front 132

Proliferation of mesenchyme around the anal membrane and deep to the superficial ectoderm creates what?

Back 132

ectodermal proctodeum or anal pit

Front 133

The lower 1/3 of the anal canl is lined by what? upper 2/3?

Back 133

ectoderm
endoderm

Front 134

What is the anatomic junctional zone between the 2 different linings of the anal canal?

Back 134

pectinate line