Embryology Of The Gut

Question 1

Where does the foregut start from and to?

Answer 1

Starts from mouth to the major duodenal papilla (proximal half)

Question 2

Where does the blood supply of the foregut come from?

Answer 2

Celiac artery

Question 3

What nerves innervate the foregut?

Answer 3

T5 - T9

Greater splanchnic nerves

Question 4

What mesenteries does the foregut have?

Answer 4

ventral and dorsal mesenteries

d=greater & v=lesser amenta

Question 5

Where does the midgut start from & to?

Answer 5

From distal half of duodenum to proximal 2/3 transverse colon

Question 6

What is the midgut supplied by?

Answer 6

Superior mesenteric artery

Question 7

What nerves innervate the midgut?

Answer 7

T10 & T11

Lesser splanchnic nerves

Question 8

What mesenteries does the midgut have?

Answer 8

dorsal mesentery only

Question 9

Where does the hindgut start from & to?

Answer 9

From 2/3 transverse colon to the anal canal

Question 10

What is the blood supply to the hindgut?

Answer 10

Inferior mesenteric artery

Question 11

What is the hindgut innervated by?

Answer 11

T12

Least splanchnic nerve

Question 12

What mesenteries does the hindgut have?

Answer 12

only dorsal mesentery

Question 13

What are the components of the foregut?

Answer 13

Mouth, Pharynx, oesophagus, stomach, proximal half of duodenum & the derivative (liver, biliary apparatus & pancreas)

Question 14

What are the components of the midgut?

Answer 14

Distal half of the duodenum
Jejunum
Ileum
Caecum
Appendix
Ascending colon
Right 2/3 transverse colon

Question 15

What are the components of the hindgut 7

Answer 15

Left 1/3 transverse colon
Decendjng colon 
Sigmoid colon
Rectum 
Anal canal

Question 16

What are the layers of the embryo that form the GI tract?

Answer 16

mesoderm and endoderm

Question 17

What does the mesoderm form?

Answer 17

connective tissue and muscle

Question 18

what does the endoderm form?

Answer 18

epithelial lining and mucosa

Question 19

What does the embryo begin to do during the 4th week and what’s it called?

Answer 19

Fold & change shape

Embryonic folding- goes from flat trilaminar disc into a cylinder

Question 20

Folding occurs in…….

Answer 20

2 planes

Question 21

What are the 2 planes in embryonic folding?

Answer 21

Horizontal plane

Medial plane

Question 22

Why does folding occur in two planes?

Answer 22

Due to the differing rates of growth of the embryonic structures

Question 23

What does folding in the horizontal plane result in?

Answer 23

Two lateral body folds

Question 24

What does folding in the medial plane result in?

Answer 24

The cranial & caudal folds

Question 25

How do both planes fold?

Answer 25

Simultaneously

Question 26

What is the endoderm mainly responsible for?

Answer 26

The development of the GI tract

Question 27

What happens as embryonic folding continues?

Answer 27

The endoderm moves towards the midline & fuses (incorporating the dorsal Part of the yolk sac) to form the primitive gut tube

Question 28

What is the primitive gut tube derived from?

Answer 28

Endoderm and visceral mesoderm

Question 29

What does the endoderm give rise to?

Answer 29

1. Epithelial lining of the digestive tract 2. Hepatocytes of the liver 3. Exocrine and endocrine cells of the pancreas

Question 30

What 3 distinct parts does the primitive gut tube differentiate into?

Answer 30

The foregut, midgut and hindgut

Question 31

What happens at the end of the 4th week of development and how does it form the mouth?

Answer 31

The oropharyngeal membrane at the cranial end of the primitive gut tube ruptures to form the mouth

Question 32

What happens during the 7th week of development and how does it form the anus?

Answer 32

The cloacal membrane at the caudal end of the primitive gut tube ruptures to form the anus

Question 33

How is the mid/hindgut tube developed?

Answer 33

``` elongation (growing of tube) herniation (sticking out of abdominal cavity) rotation retraction fixation ```

Question 34

Development of the stomach 4th Week= 7th Week= 8th Week=

Answer 34

4th Week= fusiform dilation 7th Week= 90 degree clockwise longitudinal rotation, creates lesser sac 8th Week= ventrodorsal rotation

Question 34

Development of the stomach 4th Week= 7th Week= 8th Week=

Answer 34

4th Week= fusiform dilation 7th Week= 90 degree clockwise longitudinal rotation, creates lesser sac 8th Week= ventrodorsal rotation

Question 35

Ventral mesentary= | Dorsal mesentary=

Answer 35

lesser omentum | greater omentum