Implantation and Placentation Flashcards
What day after fertilisation does blastocysts form
7-8 days
How often does cell division occur in domestic animals
Every 24 hours
How many cells are there in day 2 of developing embryo
4
How may cells in day 3-4 of developing of embryo
8
What forms on days 4-6 of embryo development
Morula - sphere of cells
What parts of the blastocyst will become embryo and placenta
Inner cell mass = embryo
Outer cells = placenta
What are the outer cells collectively called in blastocysts
Trophoblasts
What’s amnion
Inner most fluid filled membrane for protection of foetus
What’s allantois
Transport products, connection becomes umbilical cord
What’s chorion
Outer membrane, forms placenta
How long does it take in mammals after fertilisation to transport the cell to uterus
2-5 days
What is the blastocysts protected by
Zona pellucida
When does the zona pellucida decompose after fertilisation
10-11 days
What is the fluid filled space called in a blastocysts
Blasteocele
How long does implantation take
6-8 days
What are the main steps of implantation
Hatching
Apposition
Adhesion
Invasion
How does implantation happen
Blastocysts hatches out of zona pellucida
The trophoblasts protein (selectin) bind to receptors on uterine wall (pinopods)
Trophoblastic cells produce enzymes that allow invasion of endometrium
When is placenta formed
When foetal membrane becomes closely attached to the uterine wall
What increases the SA of placenta
Chorionic villi
What are the types of placenta
Diffuse
Cotyledonary
Zonary
Discoid
What animals have diffuse placenta
Pig, horse
What animals have cotyledonary placenta
Ruminants
What is cotyledon
Foetal side of placenta
What is caruncle
Maternal side of placenta
What’s placentome
cotyledon and caruncle together
What is special about cotyledonary placenta
They have numerous smaller placentae/placentome
What type of animals have zonary placenta
Predators
Describe zonary placenta
Belt distribution
Wraps around the embryo
What animals have discoid placenta
Primates, humans, rabbits, rodents
Where are the chorionic villi concentrated in in cotyledonary placenta
In little buttons - cotyledons
What are some of the functions of placenta
Hormones
Respiration
Digestion
Excretion
Is amino acid higher in maternal or foetal
Foetal
How does amino acid move from mum to foetus
Active transport
