DEVELOPMENT Session 14

Question 1

What is polyspermy and how is it prevented ?

Answer 1

• it is the entrance of more than one sperm
• When a sperm comes in contact with the egg , the egg’s plasma membrane depolarizes preventing the binding of any other sperm
• Vesicles called cortical granules release enzymes that cause the zone pellucida to become an impenetrable fertilization membrane

Question 2

What are the two layers that surround an egg

Answer 2

• The inner layer : Zona Pellucida
• The outer layer : Corona radiata

Question 3

What is morphogenesis ?

Answer 3

• This is when the embryo changes shape and cells are moving

Question 4

What is a morula ?

Answer 4

• A ball of cells that results from the cleavage stage. no cavity

Question 5

What is a blastocyst ?

Answer 5

• When the cells of the morula begin to differentiate

Question 6

What is the yolk sac ?

Answer 6

• The first annex formed and site of blood cell formation

Question 7

What is the Amnion ?

Answer 7

• It contains amniotic fluid to cushion and protect the embryo

Question 8

What is the chorion ?

Answer 8

• It develops into the fetal half of the placenta.

Question 9

What is the Allantois ?

Answer 9

• Extends away from the embryo and later gives rise to the urinary bladder

Question 10

Umbilical ________ carry oxygen-poor blood from the fetus to the placenta, and the umbilical ______ carries oxygen-rich blood from the placenta to the fetus.

Answer 10

arteries , veins