Embryology

Question 1

Name the 3 primordial germ layers

Answer 1

Ectoderm, mesoderm, endoderm

Question 2

What layers does the mesoderm divide into?

Answer 2

Splanchnic, coelom, somatic (in that order)

Question 3

What primordial germ layers forms the primitive gut? and what arises from this

Answer 3

Endoderm, a tubular structure containing the foregut, hindgut, midgut

Question 4

Which of the midgut, foregut, and hindgut are blind, for the one that isn’t, what is it connected to?

Answer 4

Fore/hindgut are blind, and midgut forms a connection with the yolk sac

Question 5

List some organs that arise from the foregut.

Answer 5

Stomach, oesophagus, pharynx, liver, pancreas, proximal duodenum

Question 6

List some organs that arise from the midgut.

Answer 6

Jejunum, ileum, caecum, ascending colon, proximal part of transverse colon, duodenum (distal to bile/ pancreatic ducts)

Question 7

List the organs formed by the hindgut.

Answer 7

Distal part of transverse colon, descending colon, rectum, proximal anal canal

Question 8

What artery supplies the formation of the hindgut organs

Answer 8

Caudal mesenteric artery

Question 9

What artery supplies the formation of the midgut organs.

Answer 9

Cranial mesenteric artery

Question 10

What artery supplies the formation of the foregut organs.

Answer 10

Coeliac artery

Question 11

Within the digestive tract, what does the ectoderm become?

Answer 11

Epithelia (oral cavity, anal canal - outer region), teeth, nerves, skin

Question 12

Within the digestive tract, what does the mesoderm become?

Answer 12

Lamina propria, submucosa, muscle layers, serosa/ adventitia, blood/ lymph vessels

Question 13

Within the digestive tract, what does the endoderm become?

Answer 13

Mucosal epithelium, mucosal glands, liver and pancreas (glandular regions only)

Question 14

Do the cranial and caudal regions of the digestive tract differentiate into organs earlier?

Answer 14

Cranial

Question 15

Does the circular or longitudinal layer of muscle develop before (within the tunica muscularis)?

Answer 15

Circular (think c comes before l in alphabet)

Question 16

At what time during gestation does cilia within the ‘oesophagus’ dissapear? and what epithelia replaces it?

Answer 16

~Halfway through, replaced by stratified squamous epithelium

Question 17

Is the outermost layer of the oesophagus adventitia or serosa?

Answer 17

tunica adventitia

Question 18

In relation to the greater and lesser curvatures, one border grows faster, resulting in the greater curvature. Is this the ventral or dorsal border?

Answer 18

Dorsal

Question 19

Name the 4 stages undergone by the intestine formation in gestation.

Answer 19

1. Growth and rotation
2. Herniation and coiling
3. Re-entry and placement
4. Completion