Anatomy- Digestive System Development

Front 1

What is the primordium of the embryonic body cavites and when does it develop?

Back 1

1. intraembryonic coelom
2. near the end of week 3

Front 2

By the beginning of week 4, what shape is the embryonic body cavity and in what areas is it?

Back 2

1. it is a horseshoe shaped cavity
2. in the cardiogenic area and lateral mesoderm

Front 3

The horseshoe shape of the embryonic body cavity. What does the curve represent?What does its lateral limbs represent?

Back 3

1. curve= future pericardial cavity
2. lateral limbs= future pleural and peritoneal cavity

Front 4

When does the folding of the embryonic discs occur?

Back 4

week 4

Front 5

During the folding of the embryonic discs in week 4, the lateral parts of the intraembryonic coelom do what?

Back 5

1. are brought together on the ventral aspect of the embryo

Front 6

When the caudal part of the ventral mesentery disappears, the right and left parts of the intraembryonic coelom merge and form what?

Back 6

1. peritoneal cavity

Front 7

As the peritoneal portions of the intraembryonic coelom come together, the splanchnic layer of the mesoderm encloses what and suspends it how and with what?

Back 7

1. primitive gut
2. suspends it from the dorsal body wall by a double-layered peritoneal membrane known as the dorsal mesentery

Front 8

Until week 7, the embryonic pericardial cavity communicates with the peritoneal cavity through what?

Back 8

paired pericardioperitoneal canals

Front 9

During week 5 and 6 what happens in the paired pericardioperitoneal canals?

Back 9

1. partitions form near the cranial and caudal ends of the these canals

Front 10

Fusion of what separates the pericardial cavity from the pleural cavities?

Back 10

1. cranial pleuropericardial membranes with mesoderm ventral to the esophagus

Front 11

Fusion of what separates the pleural cavities from the peritoneal cavity?

Back 11

1. fusion of caudal pleuroperitoneal membranes (during formation of the diaphragm)

Front 12

What does the diaphragm form from?

Back 12

1. septum transversum
2. pleuroperitoneal membranes
3. dorsal mesentery of the esophagus
4. body wall

Front 13

In what area of the liver is it directly attached to the diaphragm?

Back 13

bare area of the liver

Front 14

A posterolateral defect of the diaphragm results in what? This is due to a failure of what?

Back 14

1. results in congenital diaphragmatic hernia through the foramen of Bochdalek
2. due to a failure of fusion between the pleuroperitoneal membranes and other diaphragmatic components

Front 15

How is the posterolateral defect of the diaphragm seen on xray?

Back 15

1. chest is filled with gas-filled segments of the bowel .
2. The mediastium is displaced to the opposite hemithorax
3. The abdomen is usually lacking most of the bowel gas

Front 16

What is eventration of the diaphragm? What symptoms does it present with?

Back 16

1. disorder when all or parts of the diaphragm are replaced with elastic tissue and protrudes into the pleural cavity
2. symptoms usually include severe respiratory distress since the abdomen is pushing up into the lungs

Front 17

What is a congenital hiatal hernia?

Back 17

part of the stomach has herniated into the thoracic cavity

Front 18

What is a retrosternal (parasternal) hernia? What is this opening supposed to allow passage for?

Back 18

1.herniation of abdominal organs through the sternocostal hiatus (foramen of Morgagni)
2. opening for the superior epigastric vessels

Front 19

When does the primitive gut for and how does it do it?

Back 19

1. during week 4
2. embryo folds and incorporates the dorsal part of the yolk sac

Front 20

The endoderm of the primitive gut gives rise to what?

Back 20

1. epithelial lining of most of the digestive tract
2. biliary passages
3. parenchyma of liver and pancreas

Front 21

The epithelium of the cranial and caudal ends of the digestive tract is derived from what?

Back 21

1. ectoderm of the stomodeum and proctodeum respectively

Front 22

What are the muscular and connective tissue components of the digestive tract derived from?

Back 22

1. splanchnic mesenchyme surrounding the primitive gut

Front 23

What does the foregut give rise to?

Back 23

1. pharynx
2. lower respiratory system
3. esophagus and stomach
4. duodenum (to proximal opening of the bile duct)
5. liver
6. pancreas
7. biliary apparatus

Front 24

Because trachea and esophagus have a common origin, incomplete partitioning of what can result in what?

Back 24

1. tracheoesophageal septum
2. results in stenoses or atresias (with or without fistulas between them)

Front 25

The liver bud or hepatis diverticulum is formed from what?

Back 25

1. an outgrowth of the endodermal epithelial lining of the foregut

Front 26

The epithelial liver cords and primordia of the biliary system which develop from the hepatic diverticulum grow into what?

Back 26

1. the mesenchymal septum transversum

Front 27

Between the layers of the ventral mesentery, derived from what, the primordial cells of the biliary system differentiate into what?

Back 27

1. septum transversum
2. parenchyma of the liver and lining of the ducts of the biliary system

Front 28

When does hemopoiesis in the liver start?

Back 28

week 6

Front 29

When does bile formation in the liver start?

Back 29

week 12

Front 30

What is congenital duodenal atresia due to?

Back 30

1. failure of vacuolization and recanalization occuring after the normal solid stage of the duodenum

Front 31

When does vacuolization and recanalization of the duodenum occur?

Back 31

week 8

Front 32

When is the normal solid stage of the duodenum?

Back 32

week 5

Front 33

What does it mean to have an annular pancreas? What can it cause?

Back 33

1. results from parts of the pancreas developing around the duodenum
2. can obstruct the duodenum

Front 34

The pancreas is formed by what originating from what?

Back 34

1. dorsal and ventral pancreatic buds
2. originating from the endodermal lining of the foregut

Front 35

When the duodenum rotates to the right, what happens to the ventral pancreatic bud?

Back 35

1. it moves dorsally and fuses with the dorsal pancreatic bud

Front 36

Upon fusion, what do the ventral and dorsal pancreatic buds form?

Back 36

1. ventral- most of the head
2. dorsal- forms the rest of the pancreas

Front 37

What happens if the duct system of the dorsal and ventral pancreatic buds fails to fuse?

Back 37

an accessory pancreatic duct forms

Front 38

What does the midgut give rise to?

Back 38

1. duodenum distal to the bile duct
2. jejunum
3. ileum
4. cecum
5. vermiform appendix
6. ascending colon
7. right 1/2 to 2/3 of the transverse colon

Front 39

What happens to the midgut during week 6 and why?

Back 39

1. midgut forms a u-shaped intestinal loop herniating into the umbilical cord
2. happens due to lack of room in the abdomen (physiological umbilical herniation)

Front 40

While in the umbilical cord, the midgut loop rotates how?

Back 40

90 degrees counterclockwise

Front 41

During week 10, what happens to the intestines?

Back 41

1. the intestines return to the abdomen, rotating a further 180 degrees(reduction of the midgut hernia)

Front 42

Omphalocele, malrotations, and abnormailities of fixation of the midgut results from what?

Back 42

1. failure of return or abnormal rotation of the intestines in the abdomen

Front 43

When is the gut normally occluded and why? What can happen because of this?

Back 43

1. during weeks 5 and 6
2. due to rapid mitotic activity of its epithelium
3. stenosis, atresias and duplications may results if the recanalization fails to occur or occur abnormally

Front 44

Various remnants of the yolk sac may persist as what? What can happen because of this?

Back 44

1. Meckel's (ilieal) diverticulum
2. they can become inflamed and produce pain

Front 45

What causes Hirschsprung's disease? How is it characterized on xray?

Back 45

1. caused by the absence of postganglionic parasympathetic ganglia in the colon
2. seen as dilated small bowel and normal appearing colon

Front 46

What does the hindgut give rise to?

Back 46

1. left 1/3 to 1/2 of the transverse colon
2. descending and sigmoid colon
3. rectum
4. superior part of the anal canal

Front 47

What is the cloaca?

Back 47

caudal part of the hindgut

Front 48

What is the cloaca divided by? What is it divided into?

Back 48

1. urorectal septum
2. urogenital sinus and rectum

Front 49

What does the urogenital sinus give rise to?

Back 49

urinary bladder and urethra

Front 50

What separates the rectum and superior part of the anal canal from the outside? When does it break down?

Back 50

1. anal membrane
2. breaks down by the end of week 8

Front 51

What do anorectal malformations result from?

Back 51

abdnormal partitioning of the cloaca by the urorectal septum

Front 52

When the urorectal septum partitions the cloaca what is partitioned where?

Back 52

1. rectum and anal canal posteriorly
2. urinary bladder and urethra anteriorly

Front 53

What is the cause of most anorectal abdnormalities? What are examples of these abdnormalities?

Back 53

1. arrested growth and/or deviation of the urorectal septum in a dorsal direction
2. rectal atresia and fistulas between the rectum and urethra, urinary bladder or vagina