Embryo 1

Question 1

Growth

Answer 1

stage of cell growth

Question 2

Morphogenesis

Answer 2

development of shape and size that is controlled by gene expression

Question 3

Differentiation

Answer 3

cells turn on specific genes to form organs and tissues with specialized function

Question 4

What week does folding occur?

Answer 4

Four

Question 5

Median/Longitudinal Head Folding

Answer 5

• the brain moves posterior–> cranially, and this causes the heart and the septum transversum to move anterior
• endoderm will become foregut of the GI
• ST develops central tendon of the diaphragm
• after folding, the intra coelom lies anterior to the heart and superior to the ST, and can communicate with the extra coelom

Question 6

Median/Longitudinal Tail Folding

Answer 6

• as the embryo grows, caudal eminence projects over the cloacal membrane
• endodermal layer becomes the hind gut of the GI
• SC overgrows the tail, and pushes the cloaca and connecting stalk on the anterior side
• lastly, the allantois is partially incorporated into the embryo

Question 7

Horizontal Folding

Answer 7

• endoderm becomes mid gut of GI
• anterior fusion f the lateral folds helps reduce distance between intra/extra coelom to aid in communication, but this stops once the somatic layer fuses (pinches off)

Question 8

The intra and extra coelom communication helps to give rise to….

Answer 8

body cavities

Question 9

Mesenteries

Answer 9

suspend the organs

Question 10

Somatic mesoderm lines _____. Splanich mesoderm lines ____.

Answer 10

1. Posterior body wall

2. Endoderm

Question 11

Ectopia Cordis

Answer 11

• issue with horizontal folding (somatic layers pinch off with heart outside) where the heart gets trapped outside of the body
• the sternum is bifed, there is no pericardium, susceptible to disease, can be surgically corrected

Question 12

Pericardial cavity

Answer 12

• heart (folds so that the ST is caudal to it)
• the two pericardial coelom come together to form the cavity, and the two endocardial primordial fuse to form one heart tube

Question 13

Pericardioperitoneal canals

Answer 13

partitions form in each canal:
1. Separate pericardial cavity from the pleural cavities (heart from lungs)
2. Separate pleural cavities from peritoneal cavity
(lungs from abdomen)

*the portion of the embryonic celom that joins the pericardial cavity to the peritoneal cavity, developing into the pleural cavities.

Question 14

Pleural cavities

Answer 14

lungs

Question 15

Peritoneal cavity

Answer 15

abdomen

Question 16

The heart tube is lined by ___ pleura. The pericardial cavity is lined by ___ pleura.

Answer 16

1. Visceral

2. Parietal

Question 17

What separates the pericardial and pleural cavities?

Answer 17

pleuropericardial folds/membrane (somatic layer of LP)

Question 18

Between which two membranes do lungs develop?

Answer 18

pleuropericardial membrane and pleuroperitoneal membrane

Question 19

The ST fuses with the pleuroperitoneal membrane to form the ____.

Answer 19

Diaphragm

Question 20

Somatopleure

Answer 20

somatic mesoderm overlying embryonic ectoderm form body wall

Question 21

Splanchnopleure

Answer 21

splanchnic mesoderm & underlying embryonic endoderm form embryonic gut