Embryonic Development Flashcards
Name the cells made during the 2nd division
Blastomeres
What is the 3rd stage of division called
Morula (cluster of cells)
What do outer blastomeres differentiate into
Trophoblasts
What occurs after the blastocysts is formed
Zona pellucida pressure increases and ruptures
How does the placenta form
Extra embryonic membrane form in order to attach to endometrium
What is the function of the placenta
Feral nourishment
Protection
Hormone production
What germ layer forms the yolk sac
Endoderm
Which membrane layer develops after the yolk sac
Mesoderm
What is the chorion layer
Trophoblasts and mesodermal layer fuse
What is the allanotois
Liquid waste
What type of placenta do pigs have
Diffuse
At type of placenta do carnivores have
Zonary
What type of placenta do primates and rodents have
Discoid
What type of placenta do horses and ruminants have
Cotelydonary (placentone based)
Name the specific placenta type in a mare
A diffuse Microcotyladonary
What produces progesterone
Corpus luteum
What causes uterine contractions
Oestrodiol
How is the endometrial cup formed
Chorionionic girdle (trophoblasts that invaded the endometrium)
How are placenta classified
Distribution of villi
How many layers
What are the 3 layers in a foetus
Chorion (epithelial)
Basement membrane
Chorionic capillary blood supply
What is a haemochorial placenta
Foetus gets nutrients from maternal directly blood supply as is bathed in maternal blood
What is the epithelioochorial placenta
Doesn’t invade material endometrium
What is an endothelialchorial
Endothelial wall of mother separates it from the foetus
How does the mare recognise pregnancy
The embryo (concepts) migrates around the uterus to distribute pregnancy factors
what occurs to the oocyte after fertilisation
cytoplasm binds to sperm
releases corticol granules (makes layer that stops sperm from breaking through)
sperm nuclear membrane broken down in order to release genetic material
cause meiosis forming 2nd polar body
oocyte becomes ootid
