Development of the Gut

Question 1

Forms as a result of the lateral, cranial, and caudal body folds

Answer 1

Gut tube

Question 2

Lead to the incorporation of the dorsal portion of the endodermal yolk sac into an endoderm lined tube
within the embryo (3rd to 4th week)

Answer 2

Lateral, cranial, and caudal body folds

Question 3

The gut tube is limited at the

1. ) Cranial end by>
2. ) Caudal end by?

Answer 3

1. ) Buccopharyngeal membrane

2. ) Cloacal membrane

Question 4

In the 4th week, the buccopharyngeal membrane ruptures and establishes communication with the

Answer 4

Ectodermally lined oral cavity

Question 5

In the 7th week, the cloacal membrane ruptures and establishes communication with the

Answer 5

Ectodermally lined anal canal

Question 6

Initially, the gut tube retains its communication with the yolk sac by way of the

Answer 6

Vitelline duct

Question 7

The vitelline duct narrows and subsequently is obliterated, thus separating the

Answer 7

Gut tube from yolk sac

Question 8

Failure of the vitelline duct to obliterate can result in an open communication between the gut tube and the outside environment at the umbilicus. This is called a

Answer 8

Vitelline fistula

Question 9

An open communication between the gut tube and the outside environment at the umbilicu

Answer 9

Vitelline Fistula

Question 10

Meconium and fecal material may emerge at the umbilicus through a

Answer 10

Vitelline Fistula

Question 11

What three things may result from incomplete closure of the vitelline duct?

Answer 11

1. ) Vitelline cyst
2. ) Vitelline sinus
3. ) Meckel’s diverticulum

Question 12

A cyst within a fibrous remnant of the vitelline duct

Answer 12

Vitelline cyst

Question 13

Similar to a cyst, except it communicates with the external environment

Answer 13

Vitelline sinus

Question 14

A diverticulum from the wall of the ileum that does not communicate with the outside environment

Answer 14

Meckel’s Diverticulum (ileal diverticulum)

Question 15

Reportedly present in 2-3% of the population and is usually asymptomatic, although it may become inflamed and it may contain ectopic tissue

Answer 15

Meckel’s diverticulum

Question 16

When present, Meckel’s diverticulum is usually found on the antimesenteric side of the illeum, about

Answer 16

2-3 ft. from the ileocecal junction

Question 17

When ectopic tissue is present, it is often gastric mucosa. What does the gastric mucosa secrete that may be the cause of inflammation?

Answer 17

HCL

Question 18

If the lateral body folds do not completely meet and fuse correctly, there may be a weakness of the anterior abdominal wall which may lead to

Answer 18

Gastroschisis

Question 19

Provides an open communication between the abdominal cavity and the outside environment

Answer 19

Gastroschisis

Question 20

Gastroschisis typically occurs to the

Answer 20

Right of the umbilicus

Question 21

Failure to recanalize the gut tube results in a segment of the gut tube without a

Answer 21

Lumen (called atresia)

Question 22

Atresia occursmost commonly in the

Answer 22

Duodenum

Question 23

Evidence suggests that atresias in the jejunum and ileum are the result of vascular insult to a segment of the gut tube during

Answer 23

Development

Question 24

Obstruction of the digestive tract distal to the stomach results in severe vomiting after feeding because of the
inability to

Answer 24

Empty the stomach

Question 25

The presence or absence of bile in vomit will tell us if the obstruction is

Answer 25

Proximal (non-bilious) or Distal (bilious) to the entry of the common bile duct

Question 26

The gut tube is divided into the

Answer 26

Pharynx, foregut, midgut, and hindgut

Question 27

The portion of the gut tube from the buccopharyngeal membrane to the respiratory diverticulum

Answer 27

Pharynx

Question 28

Envaginations of the pharynx include the

Answer 28

Pharyngeal pouches, thyroglossal duct, and respiratory diverticulum

Question 29

Abnormalities in the formation of the respiratory | diverticulum may result in

Answer 29

Esophageal atresia, esophageal stenosis, or tracheoesophageal fistula

Question 30

Prevents the fetus from swallowing amniotic fluid and results in an abnormally high volume of amniotic fluid (polyhydramnios)

Answer 30

Esophageal atresia

Question 31

May result in thyroglossal cyst (median cervical cyst), | lingual thyroid or other ectopic thyroid tissue

Answer 31

Thyroglossal duct abnormalities

Question 32

The foregut is supplied by the celiac trunk and vagus nerve and gives rise to the

Answer 32

Esophagus, stomach, and part of the duodenum

Question 33

Which part of the duodenum does the foregut giverise to?

Answer 33

1st part and proximal portion of the 2nd part

Question 34

Envaginations of the foregut give rise to

Answer 34

Liver, gall bladder, and the pancreas

Question 35

The midgut is supplied by the

Answer 35

Superior mesenteric artery and vagus nerve

Question 36

The midgut gives rise to what 7 things?

Answer 36

1. ) Part of the duodenum 2. ) jejunum 3. ) Ileum 4. ) cecum 5. ) appendix 6. ) ascending colon 7. ) proximal 2/3 of transverse colon

Question 37

What part of the duodenum does the midgut give rise to?

Answer 37

distal portion of 2nd part, and 3rd and 4th parts

Question 38

The hindgut is supplied by the

Answer 38

Inferior mesenteric artery and pelvic splanchnic nerves

Question 39

The hindgut gives rise to what 5 things?

Answer 39

1. ) distal 1/3 of transverse colon 2. ) descending colon 3. ) sigmoid colon 4. ) rectum 5. ) upper part of anal canal

Question 40

Gives rise only to the epithelium of the gut tube, epithelium of the gut tube derivatives and glands derived from the epithelium

Answer 40

Endoderm

Question 41

The other layers of the gut tube organs (e.g. smooth muscle, connective tissue) are derived from

Answer 41

Splanchnic mesoderm

Question 42

The inner layer of the lateral plate mesoderm

Answer 42

Splanchnic meoderm

Question 43

During the formation of the gut tube by body folding, the splanchnic mesoderm is carried inward along with the endodermal gut tube and becomes the

Answer 43

Peritoneal covering of the gut tube and the mesenteries

Question 44

Peritoneal membranes that connect the visceral peritoneum with the parietal peritoneum

Answer 44

Mesenteries

Question 45

Serve as "bridges" to carry blood vessels, lymphatics and nerves from retroperitoneal positions to the gut tube

Answer 45

Mesenteries

Question 46

Serves as the pathway for branches of the abdominal aorta to provide blood supply to the gut, as well as a pathway for veins, lymphatics, and nerves

Answer 46

Dorsal mesentery

Question 47

The only vessel to traverse the ventral mesentery is the

Answer 47

Umbilical vein

Question 48

The adult remnant of the umbilical vein is the

Answer 48

Ligamentum teres

Question 49

The adult mesenteries derived from the ventral mesentery are the

Answer 49

Falciform ligament, and the lesser omentum

Question 50

Contains the ligamentum teres

Answer 50

Falciform ligament

Question 51

Contians the common bile duct, the proper hepatic artery, and the portal vein

Answer 51

Lesser omentum

Question 52

What are two adult mesenteries derived from the dorsal mesentery?

Answer 52

1. ) Greater omentum (includes gastrocolic ligament) | 2. ) Mesentery proper (attached to jejunum and ileum)

Question 53

Evaginates from the endodermal lining of the ventral wall of the gut tube in the region of the 2nd portion of the duodenum -enters the ventral mesentery

Answer 53

Hepatic Diverticulum

Question 54

The site of the hepatic diverticulum marks the termination of the

Answer 54

Foregut

Question 55

What do the distal and proximal ends of the hepatic diverticulum become?

Answer 55

1. ) Distal: liver and gall bladder | 2. ) Proximal: biliary duct system

Question 56

The portion of the ventral mesentery covering the liver becomes the

Answer 56

Visceral peritoneum of the liver

Question 57

The portion of the ventral mesentery between the liver and gut tube becomes the

Answer 57

Lesser omentum

Question 58

The portion of the ventral mesentery between the liver and ventral body wall becomes the

Answer 58

Falciform ligament

Question 59

The part of the liver that comes into contact with the diaphragm and is not covered by peritoneum is the

Answer 59

Bare area of the liver

Question 60

The hepatic veins exit the liver and enter the inferior vena cava through the

Answer 60

Bare area

Question 61

The bare area is surrounded by a reflection of peritoneum from visceral peritoneum of the liver onto the parietal peritoneum on the diaphragm. This is called the

Answer 61

Coronary ligament

Question 62

Develops from two pancreatic diverticula (buds) which evaginate from the endodermal lining of the gut tube in the region of the 2nd portion of the duodenum

Answer 62

Pancreas

Question 63

Arises in common with the hepatic diverticulum

Answer 63

Ventral pancreatic bud

Question 64

Initially grows into the ventral mesentery but subsequently leaves the ventral mesentery, rotates around the gut tube to enter the dorsal mesentery

Answer 64

Ventral pancreatic bud

Question 65

The ventral pancreatic duct gives rise to which three things?

Answer 65

1. ) Major pancreatic duct (of Wirsung) 2. ) lower portion of the head of the pancreas 3. ) Uncinate process

Question 66

Gives rise to the minor pancreatic duct (of Santorini) and the upper portion of the head of the pancreas and the neck, body and tail of the pancreas

Answer 66

Dorsal pancreatic duct

Question 67

Malrotation of the ventral pancreatic bud may result in -may present symptoms of bowel obstruction

Answer 67

Anular pancreas

Question 68

A ring of pancreatic tissue which surrounds the second portion of the duodenum

Answer 68

Anular pancreas

Question 69

Develops in the dorsal mesentery of the stomach (dorsal megogastrium)

Answer 69

Spleen

Question 70

Rrises from cells of the mesentery which delaminate and migrate into the plane between the layers of the mesentery

Answer 70

Spleen

Question 71

The mesentery covering the spleen becomes the

Answer 71

Visceral peritoneum of the spleen

Question 72

The mesentery between the spleen and the gut tube becomes the

Answer 72

Gastrosplenic ligament

Question 73

The mesentery between the spleen and the dorsal body wall becomes the

Answer 73

Splenorenal ligament

Question 74

Most of the splenorenal ligament fuses to become

Answer 74

Parietal peritoneum

Question 75

The blood supply to the spleen (the splenic artery) reaches the spleen by passing within the

Answer 75

Splenorenal ligament

Question 76

Does not develop from an envagination of the gut tube and thus is not connected to the gut by a duct -not part of the digestive system

Answer 76

Spleen

Question 77

Most of the gut tube retains only a dorsal mesentery. The absence of a ventral mesentery allows for

Answer 77

Mobility of the gut

Question 78

Parts of the gut tube (most of duodenum, ascending colon, descending colon, part of rectum) fuse with the body wall by way of fusion of

Answer 78

Visceral peritoneum with parietal peritoneum

Question 79

This results in the organ becoming secondarily retroperitoneal and the visceral peritoneum covering the organ being renamed

Answer 79

Parietal peritoneum

Question 80

The mesentery attaching to the organ also is renamed parietal peritoneum and the vessels within the mesentery thus become

Answer 80

Secondarily retroperitoneal

Question 81

Rotates 90 degrees around its own long axis such that the dorsal side rotates to the left and the ventral side rotates to the right

Answer 81

Abdominal foregut

Question 82

This results in the dorsal border of the stomach becoming the left border which becomes the

Answer 82

Greater curvature of the stomach

Question 83

The ventral border of the stomach becomes the right border which becomes the

Answer 83

Lesser curvature of the stomach

Question 84

For this reason, the dorsal mesentery of the stomach is attached to the greater curvature and becomes the

Answer 84

Greater omentum

Question 85

The ventral mesentery of the stomach is attached to the lesser curvature and becomes the

Answer 85

Lesser omentum

Question 86

This rotation also creates the omental bursa (lesser sac). The communication between the lesser sac and the greater sac is the

Answer 86

Epiploic formamen (of Winslow)

Question 87

The midgut develops an intestinal loop which herniates into the

Answer 87

Umbilical cord (6th week)

Question 88

While in the umbilical cord and during retraction from the umbilical cord, the midgut rotates 270 degrees around an anteroposterior axis marked by the

Answer 88

Superior mesenteric artery

Question 89

This rotation results in the jejunum being on the left and the ileum and cecum being on the

Answer 89

Right

Question 90

It also causes the colon to assume the shape of an

Answer 90

Inverted U

Question 91

Failure of the intestinal loop to completely retract from the umbilical cord (usually completely retracted by the 12th week), results in

Answer 91

Omphalocele

Question 92

When the loops of bowel are found within the umbilical cord and are separated from the amniotic fluid by the amniotic membrane covering the umbilical cord

Answer 92

Omphalocele

Question 93

The abdominal organs are within the umbilical cord and therefore covered by the amniotic membrane and separated from the amniotic fluid with

Answer 93

Omphalocele

Question 94

The abdominal organs are outside of the umbilical cord, are not covered by the amniotic membrane and are in contact with amniotic fluid with

Answer 94

Gastroschisis

Question 95

What is more common (1/4000 vs. 1/8000) omphalocele or gastroschisis?

Answer 95

Omphalocele

Question 96

Is more often associated with chromosomal | abnormalities and other congenital defects and has an increased incidence with older maternal age (>40 years)

Answer 96

Omphalocele

Question 97

Less frequently associated with other abnormalities and has an increased incidence with younger maternal age (<20 years)

Answer 97

Gastroschisis

Question 98

Babies with omphalocele have a much poorer survival rate, primarily because of associated defects of the

Answer 98

Heart and Kidneys