Formation of the Body Cavities

Question 1

What are the 3 phases of organ development?

Answer 1

growth
morphogenesis - build size and shape due to gene expression
differentiation - cells turn on diff things to perform very specific functions

Question 2

What nerve innervates the diaphragm?

What are its spinal nerve roots?

Answer 2

phrenic N

C3-C5

Question 3

What are the pericardial coelom?

Answer 3

originally 2 coelom in lateral plate mesoderm –> merge to form one coelom around developing heart

Question 4

What is somatopleura?

Answer 4

somatic mesoderm and ectoderm

Question 5

What does the cephalad longitudinal folding result in?

Answer 5

brain overgrowth –> folds anterior to oropharyngeal membrane and heart –> get septum transversum that is inferior to to developing heart

Question 6

What is splanchnopleura?

Answer 6

splanchnic mesoderm and endoderm (gut)

Question 7

What structure do parietal membrane arise from?

Answer 7

somatic lateral plate mesoderm

Question 8

What structure do visceral membrane structures arise from?

Answer 8

splanchnic mesoderm

Question 9

What are the endocardial primordia?

Answer 9

2 heart tubes that will merge to form 1

Question 10

What does the pleuroperitoneal membrane do?

Answer 10

separates the pleural and peritoneal cavities

Question 11

Where do the lungs develop?

Answer 11

In the area between the pleuropericardial membrane and the pleuroperitoneal membrane

Question 12

When are the major organs formed during development?

Answer 12

weeks 3-8

Question 13

At what time do you have a common intraembryonic U-shaped coelom?
What is it formed from?

Answer 13

day 21

formed from coelomic spaces

Question 14

What type of mesoderm does the pleuroperitoneal membrane arise from?

Answer 14

somatic mesoderm

Question 15

What is another name for the septum transversum?

Answer 15

central tendon

Question 16

How is the pericardial cavity separated from pleural canals?

Answer 16

by pleuropericardial folds

Question 17

What does the diaphragm form from?

Answer 17

pleuroperitoneal membrane grows ventrally toward the septum transversum and they fuse –> tissue from body wall pulled into diaphragm

Question 18

What folding results in the formation of the intraembryonic coelom?

Answer 18

horizontal folding

Question 19

What are the major sequences of caudal longitudinal folding?

Answer 19

spinal overgrowth –> folds along w/ hindgut endoderm and allantois–> end up with extraembryonic coelom

Question 20

What is ectopia cordis?

Answer 20

malfunction in horizontal folding that results in the heart forming outside of the body and a split sternum

Question 21

What happens in horizontal folding?

Answer 21

somatic lateral plate mesoderm folds down around umbilical vessel and splanchnic mesoderm –> doesn’t completely close –> now you have intraembryonic coelom and the midgut formed by umbilical vesicle shrunken up

Question 22

What is the order and timing of longitudinal folding

Answer 22

cephalad fold first in early 4th week

caudal fold next in late 4th week

Question 23

In what embryonic structure does the phrenic nerve start to innervate the diaphragm?

Answer 23

in the pleuropericardial folds

Question 24

Where do the bronchial buds grow?

Answer 24

into the pericardioperitoneal canals

Question 25

Along what planes does the embryo fold?

When does this occur?

Answer 25

median and horizontal planes
week 4 (simultaneously fold)