Embryo/Teratogenesis

Question 1

The coeliac artery supplies the (fore/mid/hindgut).

Answer 1

Foregut

Question 2

The Superior mesenteric artery supplies the (fore/mid/hindgut).

Answer 2

Midgut

Question 3

The Inferior mesenteric artery supplies the (fore/mid/hindgut).

Answer 3

Hindgut

Question 4

Which parts of the GIT arise from the foregut?

Answer 4

1) Esophagus
2) Stomach
3) 1st 2 parts of duodenum
4) Liver
5) Gallbladder

Question 5

Where do the bones, muscles and cartilage in the head and neck region arising from?

Answer 5

Pharyngeal arches

Question 6

In embryonic development what supplies the pharynx?

Answer 6

Thoracic aorta

Question 7

Where do the esophageal epithelium and glands arise from?

Answer 7

Foregut endoderm

Question 8

Where do the esophageal muscles arise from?

Answer 8

Mesoderm surrounding foregut

Question 9

Initially, the embryonic esophageal lumen is filled, in development it undergoes ________ to become hollow.

Answer 9

Recanalisation

Question 10

What are 3 examples of components of the GIT system is derived from the endoderm?

Answer 10

1) Mucosal epithelium
2) Mucosal glands
3) Submucosal glands

Question 11

What are 6 examples of components of the GIT system is derived from the mesoderm?

Answer 11

1) Lamina propria
2) Muscularis mucosa
3) Submucosal connective tissue
4) Blood vessels
5) Muscularis externa
6) Adventitia/serosa

Question 12

What component of the GIT system is derived from the neural crest cells?

Answer 12

Nerves of the submucosal and myenteric plexus

Question 13

The dorsal border of the mesogastrium has (greater/lesser) curvature than the ventral border. During clockwise rotation, the dorsal mesogastrium would have (greater/lesser) momentum than the ventral mesogastrium.

Answer 13

Dorsal → greater curvature and momentum
Ventral → lesser curvature and momentum

Question 14

Describe the rotation(s) of the embryonic stomach.

Answer 14

1) 90 degree clockwise → creates omental foramen (allows for communication btwn greater and lesser sacs of peritoneal cavity)

2) frontal plane → repositions superior and inferior regions of stomach

Question 15

Rotation of the stomach brings the duodenum into position turning it into a __________ loop on the (right/left) side of the abdominal cavity.

Answer 15

C-shaped loop on the right side of the abdominal cavity

Question 16

Initially, the embryonic duodenum lumen is filled, in development it undergoes ________ to become hollow.

Answer 16

recanalisation

Question 17

The proximal 1/3 of the duodenum arises from the ________ while the distal 2/3 arises from the ______.

Answer 17

proximal 1/3 from foregut
distal 2/3 from midgut

Question 18

What do the liver, gall bladder and biliary duct system arise from?

Answer 18

Liver bud/hepatic diverticulum

Question 19

Which germ layer do hepatocytes arise from?

Answer 19

Endoderm

Question 20

Which germ layer do Kupffer cells arise from?

Answer 20

Mesoderm

Question 21

Which germ layer do hepatic hematopoietic tissues arise from?

Answer 21

Mesoderm

Question 22

How does the pancreas form?

Answer 22

Dorsal and ventral pancreatic buds unit to give rise to 1 pancreas as duodenum rotates

Question 23

Which germ layer do pancreatic parenchyma arise from?

Answer 23

Endoderm

Question 24

Which germ layer do pancreatic islets arise from?

Answer 24

Mesoderm

Question 25

How does the spleen form?

Answer 25

Developed from mesenchymal cells in the fold of dorsal mesogastrium

Question 26

The gastrosplenic and splenorenal ligaments are remnants of what embyronic structure?

Answer 26

Remnants of the dorsal mesogastrium

Question 27

What are 5 congenital anomalies associated with the foregut?

Answer 27

1) Esophageal atresia 2) Esophageal stenosis 3) Congenital hiatal hernia 4) Pyloric stenosis 5) Annular pancreas

Question 28

What is an esophageal atresia?

Answer 28

Abnormal tracheoesophageal septum (usually occurs w a tracheoesophageal fistula) - lead to complications (eg. inflammation, infection)

Question 29

What is an esophageal stenosis?

Answer 29

Narrowing of the esophageal lumen due to failure to recanalise

Question 30

What is a congenital hiatal hernia?

Answer 30

Enlarged esophageal hiatus due to defect/weakness in diaphragmatic muscles

Question 31

What is a pyloric stenosis?

Answer 31

Hypertrophy of smooth muscle of the pyloric sphincter - associated with forceful vomiting shortly after feeding

Question 32

What is an annular pancreas?

Answer 32

Abnormalities in rotation of ventral bud of the pancreas - ventral bud surrounds/constricts duodenum → blockage

Question 33

Which parts of the GIT arise from the midgut (7)?

Answer 33

1) Distal 2/3 of duodenum 2) Jejunum 3) Ileum 4) Coecum 5) Appendix 6) Ascending Colon 7) Proximal 2/3 of transverse colon

Question 34

How does physiological herniation occur in GIT development?

Answer 34

Formation of small intestine - Primary intestinal loop (from midgut) herniates through vitelline duct - cranial loop → jejunal and ileal portions of small intestine - caudal loop → coecum, appendix, ascending colon, proximal 2/3 of transverse colon

Question 35

How does the large intestine form?

Answer 35

Develop as dilation of caudal limb of herniated primary intestinal loop

Question 36

What are 3 congenital anomalies associated with the midgut?

Answer 36

1) Meckel's diverticulum 2) Congenital umbilical hernia 3) Abnormal rotation of midgut

Question 37

What is meckel's diverticulum?

Answer 37

Remnant of vitelline duct persists as ileal diverticulum - asymptomatic but susceptible to infections

Question 38

What is a congenital umbilical hernia?

Answer 38

Incomplete closure/weakness of umbilical ring - weak point in abdominal wall → prone to herniation - incomplete closure of umbilical ring → protrusion of abdominal contents

Question 39

What are 2 abnormal rotations of the midgut?

Answer 39

1) Non-rotation 2) Mixed rotation of midgut - cephalic and cranial loops rotate incorrectly

Question 40

Which parts of the GIT arise from the hindgut (4)?

Answer 40

1) Distal 1/3 of transverse colon 2) Descending colon 3) Sigmoid colon 4) Upper part of anal canal

Question 41

The hindgut ends with the _____.

Answer 41

Cloaca

Question 42

The ______ divides the cloaca into the _____ and ______.

Answer 42

Urorectal septum 1) urogenital sinus (anterior) 2) anorectal (posterior)

Question 43

The superior 2/3 of the anorectal canal forms the _____.

Answer 43

distal portion of hindgut

Question 44

The inferior 1/3 of the anorectal canal is formed from which germ layer?

Answer 44

Ectoderm

Question 45

What is a congenital abnormality associated with the hindgut?

Answer 45

Imperforate anus

Question 46

What is an imperforate anus?

Answer 46

A congenital anorectal malformation - normal anal opening absent at birth

Question 47

What is the mesentery?

Answer 47

Mesenchymal (connective tissue) covering passing over developing gut tube from posterior body wall. - suspends the gut and organs within abdomen

Question 48

What does the dorsal mesentery form (5)?

Answer 48

1/2) Mesenteries of Large and Small intestine 3) Mesentery of mesocolon 4) Mesentery of mesoappendix 5) Greater omentum

Question 49

What does the ventral mesentery form (2)?

Answer 49

1) Lesser omentum 2) Falciform ligament

Question 50

What are 3 primary retroperitoneal organs?

Answer 50

1) Thoracic esophagus 2) Rectum 3) Anus

Question 51

What are 4 secondarily retroperitoneal organs?

Answer 51

1) Proximal 2/3 duodenum 2) Pancreas 3) Ascending colon 4) Descending colon