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Question 1

Requirements for sperm motility

Answer 1

Energy source, pH increase

Question 2

Explain capacitation

Answer 2

Removal of some protective membranes by female secretions: must remove membrane to release enzymes in the acrosomes

Increase of motility

Question 3

Acrosome reaction

Answer 3

Enzymes released from the sperms head, create a path that allow the sperm to penetrate the zona pellucida

Question 4

Fast block to polyspermy

Answer 4

Fast and temporary depolarization of the egg plasma membrane

Question 5

Slow block to polyspermy

Answer 5

Slow and permanent. Sperms entrance to the egg release calcium ions -> cortical reaction: wave of lysosomes with enzymes -> enzymes cross link the ZP and make it impenetrable

Question 6

Zygote formation process

Answer 6

Fusion of male and female pronuclei, fusion of plasma membranes of oocyte and sperm. Completion of Meiosis II

Question 7

Zygote cleavage, stage afterwards

Answer 7

Rapid series of mitotic divisions forming blastomeres

Question 8

Morula stage, stage afterwards

Answer 8

Spheroidal stage of more than 16 blastomeres, followed by blastocyst

Question 9

Blastocyst formation, description

Answer 9

Accumulation of fluid in morula forms blastocyst.

Trophoblast (perimeter cells) will form placenta
Embryoblast (inner cells) will form embryo

Question 10

Implantation process

Answer 10

Blastocyst attaches to endometrium and implants into uterine wall. Implantation is completed when blastocyst is entirely surrounded

Separate into two layers (2 week stage)

Question 11

Pairs of structures during week two

Answer 11

Trophoblast divides into two layers
Embryo consists of epiblast and hypoblast
Two cavities are present: amniotic and yolk sac

Question 12

Gastrulation process

Answer 12

Process by which the bilaminar embryonic disk is converted into the ectoderm, mesoderm, and endoderm which develops into all of the organs and tissues of the body