Development of Digestive System (Exam 3)

Question 1

The primitive gut is closed at both ends by ________ membranes.

Answer 1

bilaminar

Question 2

What are the 2 bilaminar membranes of the primitive gut?

Answer 2

1. oropharyngeal membrane
2. cloacal membrane

Question 3

The primitive gut is suspended to body wall by ___________.

Answer 3

dorsal mesentery

Question 4

What provides blood supply to the primitive gut?

Answer 4

ventral branches of aorta

Question 5

Digestive system is the main organ system derived from embryonic __________.

Answer 5

endoderm

Question 6

What are the 4 divisions of the primitive gut?

Answer 6

1. pharynx
2. foregut
3. midgut
4. hindgut

Question 7

Which division of the primitive gut is the largest and forms 2/3 of the descending colon?

Answer 7

midgut

Question 8

Which 4 tissues/organs are derived from the foregut?

Answer 8

esophagus
stomach
liver
pancreas

Question 9

_______ of the walls of the foregut results in changes in position and appearance which derives the stomach.

Answer 9

differential growth

Question 10

The _______ of the stomach is derived from the dorsal dilation of foregut, while ________ is from the ventral dilation.

Answer 10

greater curvature
lesser curvature

Question 11

What is the order of differentiation of the ruminant stomach compartments?

Answer 11

1. rumen
2. reticulum
3. omasum
4. abomasum

Question 12

Match the ruminant stomach compartment to how it is derived:

1. as caudoventral pocket of fundus
2. as expansion of fundus
3. as dilation of pyloric region
4. as expansion of lesser curvature

Answer 12

1. reticulum
2. rumen
3. abomasum
4. omasum

Question 13

When do the compartments of the ruminant stomach reach adult size?

Answer 13

after 1 year of age

Question 14

What is the largest gland in the body?

Answer 14

liver

Question 15

Which 3 species do not have a gallbladder?

Answer 15

horse
rat
whale

Question 16

The liver begins as a hepatic diverticulum or (dorsal/ventral) outgrowth of the foregut.

Answer 16

ventral

Question 17

Liver sinusoids are formed by proliferation of endodermal cells into _____ that anastomose around which 2 veins?

Answer 17

cord
vitelline + umbilical Vv

Question 18

The expansion of the developing liver narrows the connections with the foregut and the hepatic ducts merge to form ______________.

Answer 18

common hepatic duct

Question 19

The cystic duct joins the hepatic duct to form ________.

Answer 19

bile duct

Question 20

Where does the bile duct open?

Answer 20

at the site of origin of the liver bud

Question 21

The liver expands temporarily into what structure that is later the tendinous center of the diaphragm?

Answer 21

septum transversum

Question 22

The ventral mesentery is divided by the liver into what 2 structures?

Answer 22

1. lesser omentum
2. falciform ligament

Question 23

What are the 2 parts of the lesser omentum?

Answer 23

1. hepatogastric ligament
2. hepatoduodenal ligament

Question 24

The origin of hepatic diverticulum is shifted dorsally by differential growth of ________.

Answer 24

duodenum

Question 25

What digestive organ has dual origin?

Answer 25

pancreas

Question 26

The dual origin of the pancreas is made up of the ____ and ____ diverticulum.

Answer 26

dorsal + ventral

Question 27

The dorsal diverticulum forms the (right/left) lobe of the pancreas with the _______ duct.

Answer 27

left accessory

Question 28

The ventral diverticulum forms the (right/left) lobe of the pancreas with the ________ duct.

Answer 28

right pancreatic

Question 29

Match each species to which pancreatic ducts they have present: 1. dog/horse 2. cat/small ruminant 3. pig/ox

Answer 29

1. pancreatic + accessory 2. only pancreatic 3. only accessory

Question 30

During midgut development, the loop rotates around the axis of ________ A.

Answer 30

cranial mesenteric

Question 31

What determines the direction of rotation of the midgut?

Answer 31

connection to yolk sac and uneven growth

Question 32

The sequence of the withdrawal of loop of midgut determines what?

Answer 32

final placement of intestines

Question 33

Cranial limb of midgut passes to the (right/left) (caudal/in front of) cranial mesenteric A.

Answer 33

left caudal

Question 34

Caudal limb of midgut passes to (right/left) (caudal/in front of) cranial mesenteric A.

Answer 34

right in front of

Question 35

The cranial limb of the midgut forms what 2 structures?

Answer 35

duodenum jejunum

Question 36

Complete rotation of the midgut involves ____ degrees (clockwise/counterclockwise) around the cranial mesenteric A.

Answer 36

270 counterclockwise

Question 37

Complete rotation of the midgut forms what structure?

Answer 37

root of mesentery

Question 38

Formation of a secondary loop of the ascending colon forms a ______ in pigs and ruminants, and a ____ in horses.

Answer 38

spiral colon bend colon

Question 39

What 3 structures are derivates of the hindgut?

Answer 39

1. part of descending colon 2. rectum 3. anal canal

Question 40

Term for common chamber for digestive and urogenital systems

Answer 40

cloaca

Question 41

The cloaca persists in what 3 adult species?

Answer 41

birds reptiles amphibians

Question 42

The cloaca is divided by a urorectal septum into what 2 structures?

Answer 42

1. anal canal 2. urogenital sinus

Question 43

Term for caudal diverticulum of hindgut that forms splanchnic mesoderm + yolk sac forming urinary bladder and urachus.

Answer 43

allantois

Question 44

Term for first stool of green material from bile salts and swallowed amniotic fluid.

Answer 44

meconium

Question 45

Term for temporary occlusion of gut by epithelial proliferation.

Answer 45

gut atresia

Question 46

(T/F) Gut atresia anomalies occur simultaneously.

Answer 46

False - related anomalies can occur at any level

Question 47

When should meconium be completely eliminated by?

Answer 47

4th day after birth

Question 48

What is a common cause of colic in equine neonates?

Answer 48

meconium retention

Question 49

What are the two most common gut defects?

Answer 49

1. atresia 2. stenosis

Question 50

3 possible causes of gut atresia and stenosis

Answer 50

1. fetal vascular "accidents" 2. lack of re-canalization 3. gut rotation defects

Question 51

(T/F) In some species, gut defects such as atresia and stenosis, are genetic conditions.

Answer 51

True

Question 52

Term for imperforated anus due to persistent anal membrane.

Answer 52

anal atresia

Question 53

Term for sign of anal atresia where animal tries but cannot defecate.

Answer 53

tenesmus

Question 54

How do you treat/manage anal atresia?

Answer 54

surgery

Question 55

Term for ectopic anal opening due to error in separation of cloaca.

Answer 55

fistula

Question 56

Neuromuscular gut disorder where there is a lack of relaxation of esophageal sphincter relaxation which leads to regurgitation of undigested food.

Answer 56

congenital megaesophagus

Question 57

How is congenital megaesophagus managed? (2 ways)

Answer 57

bailey chair feeding PEG tube

Question 58

Congenital megaesophagus is the most common cause of _______ in cats and dogs.

Answer 58

regurgitation

Question 59

Congenital megacolon is the lack of _____ function due to the absence of _____ ganglia.

Answer 59

motor myenteric

Question 60

3 symptoms of congenital megacolon

Answer 60

1. tenesmus 2. constipation 3. abdominal distension

Question 61

"Mega" conditions like megacolon involve a lack of migration of what embryonic cells?

Answer 61

neural crest cells

Question 62

Term for incomplete closure of abdominal wall at umbilicus.

Answer 62

congenital umbilical hernia

Question 63

Which species has the highest incidence of congenital umbilical hernia?

Answer 63

pigs

Question 64

Term for when part of the body wall is open and not covered by peritoneum.

Answer 64

omphalocele