Body Folding

Question 1

Week 4

Answer 1

• primitive streak becomes the neural tube
• 3 germ layers become prolific and populate
• lots of gene expression
• lots of mitosis
• somites
• neural crest cells
• gut tube formation
• muscle specification

Question 2

Body folding results in the creation of which two structures?

Answer 2

1.) Head and tail region
2.) Vertebral body form

Question 3

What factors drive folding?

Answer 3

1.) Cell shape changes
2.) Increased number of cells
3.) Chemical communication

Question 4

What’s the purpose of body folding?

Answer 4

• neurulation begins
• cranial neuropore closes
• caudal neuropore closes and primitive streak disappears

Question 5

Body folding details

Answer 5

• yolk sac diminishes
• body takes on cylindrical shape with regions
• folds of tissue fuse and meet with each other
• folds on 2 planes

Question 6

Body takes on cylindrical shape with these regions

Answer 6

1.) Cranial (head)
2.) Caudal (tail)
3.) Lateral body fold

Question 7

Cranial (head) region

Answer 7

view sagittal

Question 8

Caudal (tail)

Answer 8

view sagittal

Question 9

Lateral body fold

Answer 9

view xs

Question 10

What are the 2 planes during folding?

Answer 10

1.) Horizontal plane
2.) Median plane

Question 11

Horizontal plane

Answer 11

Lateral body folds

Question 12

Median plane

Answer 12

Cranial and caudal folds

Question 13

Cardiogenic area (heart)

Answer 13

horseshoe-shaped mesodermal tissue

Question 14

Septum transversum

Answer 14

separates the coelom into thoracic and abdominal cavities
- ventral mesentery of stomach and duodenum
- day 22

Question 15

________ growth of the neural plate causes the cranial rim to fold under

Answer 15

Forward

Question 16

What does forward growth form?

Answer 16

ventral surface of future face, neck, and chest

Question 17

Forward growth pushes the oropharyngeal membrane to the region of the future ______

Answer 17

mouth

Question 18

Forward growth pushes the cardiogenic area and septum transverse toward the future ______

Answer 18

chest

Question 19

_____ growth due to lengthening of neural tube, and somites overgrow caudal rim of yolk sac

Answer 19

caudal

Question 20

Caudal portion folds under traveling _______

Answer 20

cranially

Question 21

What does the caudal portion form?

Answer 21

ventral surface and meets with neck of yolk sac

Question 22

What happens to the yolk sac during caudal growth?

Answer 22

it lengthens and constricts

Question 23

In caudal growth, the roots of the connecting stock contains a slender endodermal hindgut diverticulum called what?

Answer 23

allantois

Question 24

Lateral growth

Answer 24

• the embryonic disc flex sharply ventrally constricting and narrowing the neck of the yolk sac

Question 25

During lateral growth, the lateral sides meet up and “zip” toward the location of the future _________

Answer 25

umbilicus

Question 26

During lateral growth, all 3 germ layers ______ and _____

Answer 26

meet; fuse

Question 27

T/F During lateral growth, the tube within a tube plan is established

Answer 27

True

Question 28

Schisis

Answer 28

split or cleave

Question 29

Gastroschisis

Answer 29

the bowel herniates through an opening in the body wall and is not contained within a membranous sac

Question 30

Omphal

Answer 30

umbilicus