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Flashcards in First Week of Development Deck (17):
1

Where does fertilization occur?

the ampulla of the uterine tube

2

When can a sperm fertilize an egg?

only after undergoing capacitation and acrosome reaction

3

Capacitation

period of conditioning that takes place in female reproductive tract lasting 7 hours

4

Acrosome reaction

induced by zona proteins after the sperm binds to the zona pellucida, this process releases enzymes that allow the sperm to penetrate the zona pellucida

5

How many phases does fertilization have?

6 phases

6

Phase 1 of fertilization

passage of sperm through the corona radiate of the oocyte

7

Phase 2 of fertilization

penetration of the zona pellucida, the release of acrosomal enzymes allows the sperm to penetrate the zona pellucida and come in contact with the plasma membrane of the oocyte

8

Phase 3 of fertilization

fusion of the plasma cell membranes of the oocyte and sperm, sperm head and tail enter the oocyte

9

Phase 4 of fertilization

completion of the second meiotic division of the oocyte- forms the female pronucleus and the second polar body

10

Phase 5 of fertilization

formation of the male pronucleus- the tail degenerates and the nucleus of the sperm enlarges, DNA replication occurs

11

Phase 6 of fertilization

breakdown of the pronuclear membranes and restoration of diploid number of chromosomes

12

Cleavage

division of the zygote begins approx. 30 hours after fertilization

13

What are the cells that become smaller during mitotic division of the zygote called?

balstomeres

14

Morula

the 16 to 32 cell stage

15

Blastocyst formation

around day 4 the morula enters the uterus, uterine fluid penetrates through the zona pellucida to the intercelluar space of the inner cell mass, the fluid filled space is called the blastocystic cavity

16

Blastomeres are seperated into two parts

Inner cell mass is the embroblast that gives rise to the embryo proper, and the outer cell mass or tropoblast that forms the placenta

17

When does implantation occur?

6 days after fertilization