Embryogenesis

Question 1

What are teratogens?

Answer 1

Substances that interfere with development

Question 2

What are morphogens?

Answer 2

They promote development down a specific cell line

Question 3

What happens to the neural folds?

Answer 3

Fuse to become neural tube –> Becomes CNS

Question 4

What happens to the neural crest cells?

Answer 4

PNS + specific cell types in other tissues (calcitonin producing cells in thyroid, and melanocytes for example)

Question 5

What happens during the 1st trimester?

Answer 5

organogenesis

Question 6

What happens during the 2nd trimester? 4 things

Answer 6

1. Tremendous growth
2. Movement begins
3. Face forms
4. Digits elongate

Question 7

What happens during the third trimester? 3 things

Answer 7

1. Growth
2. Brain development
3. Transfer of antibodies

Question 8

What are deustrosomes?

Answer 8

Blastopore becomes anus –> anus to mouth formation of the gut tube in humans

Question 9

What cells form the placenta?

Answer 9

Trophoblasts

Question 10

What germ layer is the notochord made of?

Answer 10

Mesoderm

Question 11

What is the developmental stage with the greatest nuclear to cytoplasmic ratio?

Answer 11

blastula

Question 12

What is cell differentiation caused by? What does the cell be differentiated need to be?

Answer 12

caused by inducers: usually growth factors.

the cell being induced = responder → MUST BE COMPETENT

Question 13

What are the stages following embryo formation

Answer 13

1. Morula
2. Blastula
3. Gastrula (3 primary germ layers)
4. Neurulation

Question 14

What happens for the zygote to become an embryo?

Answer 14

First cleavage of the cell; no longer unicellular