Fertilization and Embryonic Development

Question 1

What is fertilization?

Answer 1

The fusion of sperm and egg to become a zygote

Question 2

What are the 4 main steps of fertilization?

Answer 2

1. Starts with cell division
2. Becomes a zygote w/ multiple cells
3. Becomes a blastula
4. Tissue layers of the fetus begin to develop

Question 3

In the 1st step of fertilization, cell division occurs. What are the two ways in which this could happen?

Answer 3

1. Meroblastic= Partial division of the zygote, leaving some as yolk for the embryo to feed off of as it develops
2. Holoblastic= Complete division of the zygote, leaving no yolk for the embryo to feed off of as it develops

Question 4

What are the 3 steps that occur in the 1st 8 days of embryonic development?

Answer 4

1. Initial fertilization of egg AKA beginning of the zygote
2. Undergoes a # of cell divisions
3. Leaves us with a hollow ball w/ a small mass on top AKA the inner cell mass

Question 5

The inner cell mass that is left at the end of the 1st 8 days of embryonic development is called?

Answer 5

The epiblast

Question 6

The layer of cells that surrounds the inner cell mass is called?

Answer 6

The hypoblast