Embryonic Development And Placentation Flashcards
Three layers of blastocyst (day 14)
Ectoderm
CNS, hair, hooves
Mesoderm
Skeletal system, kidney, muscle
Endoderm
Digestive system, pancreas, liver4 placental membranes
Yolk sac
Amnion
Allantois
Chorion
Chorion
Attaches to uterus, produces hormones, absorbs nutrients
Allantois
Fused with chorion, carries blood vessels
Amnion
Protects fetus, lubrication during parturition
Yolk sac
Early nutrient supply
Two types of implantation
Superficial - chorion fuses to uterine endometrium
Interstitial - embryo invades and develops in endometrium
Four main placental types
Diffuse (mare/sow) - villi cover surface of chorion
Zonary (dogs/cats) - villi form a band around chorion
Cotyledonary (cow/ewe) - villi localized at cotyledons
Discoidal (primates) - villi cover 1/2 placental surface
Cow place ration
30-35 days
Sow placentation
12-20 days
Ewe placentation
18-20 days
Mare placentation
50-60 days
Human placentation
8-10 days
Cat placentation
12-14 days
Dog placentation
16-18 days
Epithelialchorial fusion
6 layers
Pigs
Horses
Ruminants
Endothelialchorial fusion
5 layers
Dogs and cat
Hemochorial fusion
3 layers
Primates
Rodents
Blastocyst 4 parts
Day 6
Inner cell mass
Zona pellucida
Trophoblast
Blastocoele
Main function of placenta
Provide fetal nutrition
Details placental function
Blood gas exchange at chorion
Converts glucose to fructose
Highly permeable to water and electrolytes
Each individual cell is called
Blastomere
Embryo enters uterus around day
4-5
What is a morula?
Embryo with Over 32 cells
Maternal recognition of pregnancy
Prostaglandin F 2 alpha is inhibited
Corpus luteum is protected from PGF2a
