Embryology: Overview and the First Week of Human Development

Question 0

Preimplantation occurs at (timeline)

Answer 0

Week 1

Question 1

Fertilization occurs at (timeline)

Answer 1

Day 0

Question 2

Early development and gastrulation occurs at (timeline)

Answer 2

Weeks 2-3

Question 3

The embryonic period (morphogenesis) occurs at (timeline)

Answer 3

Weeks 3-8

Question 4

The fetal period (growth and terminal differentiation) occurs at (timeline)

Answer 4

Weeks 9-38

Question 5

When are all of a woman’s eggs created?

Answer 5

During the second month of embryogenesis

Question 6

Oogenesis

Answer 6

• Process by which cells mature into oocytes within the ovary
• Proceeds until birth

Question 7

Primary oocytes develop at

Answer 7

the end of the reproductive period

Question 8

Activated oocyte travels

Answer 8

• is released from the ovary and travels toward the uterus

Question 9

Fertilization takes place in the

Answer 9

ampulla of the uterine tube

Question 10

Zygote

Answer 10

Is the combination of the genetic material of the sperm with the genetic material of the egg to form a single nucleus

Question 11

32 cell stage

Answer 11

• Fluid begins to accumulate within the zygote, transforming it into a hollow sphere
• Wall is 1 cell thick
• Inner cell mass is 2-3 cells thick

Question 12

Inner cell mass of blastocyst gives rise to

Answer 12

Embryo proper and embryonic material

Question 13

Remainder of blastocyst (except for inner cell mass) is known as ___ and gives rise to ____

Answer 13

• Known as trophectoderm

- Contributes to placenta and embryonic membranes

Question 14

Blastocyst cavity is called the

Answer 14

Primary yolk sac

Question 15

Day 4

Answer 15

• Blastocyst reaches the uterine cavity

Question 16

Day 6

Answer 16

When blastocyst adheres to the uterus

Question 17

Implantation (definition)

Answer 17

Penetration of the endometrial (uterine) epithelium and invasion of the endometrial stroma by growth of the trophectoderm is called implantation

Question 18

Ectopic pregnancy

Answer 18

• Occurs when blastocyst implants at sites other than in the normal uterine wall

Question 19

Placenta previa

Answer 19

• Implantation at the bottom of the uterus, such that the placenta blocks the opening of the cervix