Embryonic development & pregnancy Flashcards
Between days 7 and 9 a ______________ forms.
blastocyst
The most invasive type of placenta is the diffuse placenta. True or False?
False; the discoid placenta is the most invasive
Cotyledonary placentas are found in which animals:
cows & sheep
After the 16-cell stage, a ______ is formed which is a packed mass of cells
morula
What part of the blastocyst will become the fetus?
inner cell mass
What part of the blastocyst becomes the placenta?
trophoblast cells (trophectoderm)
The pocket of fluid where the inner cell mass sits
blastocoel
What are the 4 functions of the placenta?
protection
nutrition
respiration
hormone production
We find this type of placenta in sows and mares
diffuse
The outer layer of the placenta is referred to as the…
chorion
Where blood crosses over in fetal pigs
chorionic villi
In pigs, the maternal side of the placenta is called
rugae
In pigs, the fetal side of the placenta is called
areola
What do horses have instead of chorionic villi for blood crossover?
microcotelydans
Type of placenta found in dogs, ferrets & cats (carnivores mostly)
zonary
The area of a zonary placenta that contacts the endometrium (only place where blood can cross over)
central girdle/belt
Type of placenta found in humans, primates and rodents
discoid
Type of placenta found in cows and sheep
cotelydonary
Cotelydons are on the _______ side
fetal
Caruncles are on the _______ side
maternal
In cows, the caruncles are… (concave/convex?)
convex
In sheep the caruncles are…
concave
Cotelydonary placentas are considered to be…
noninvasive
A cotyledonary placenta is the least efficient - why?
there are more layers for nutrients to travel through between maternal and fetal blood
A discoid placenta is the most efficient - why?
Fewer layers for nutrients to travel through between mother and fetus
Logarithmic growth chart used to predict fetal age
crown-rump length
Energy requirements for a mother during the first stages of gestation are…low/high-why?
low since growth is slow during the first stages
Energy requirements for a mother during the last stages of gestation are low/high-why?
high since fetal growth is quicker during the last stages of gestation
Cow gestation length
9 months (282 days)
Ewe, doe gestation length
5 months (150 days)
Sow gestation length
3 months, 3 weeks and 3 days (112-114 days)
Mare gestation length
11 months (340 days)
Human gestation length
9 months (284 days) -similar to cows
Mice gestation length
21 days
Elephant gestation length
2 years (616 days)
What does crown-rump length growth curve suggest about energy requirements during the first stages of gestation?
Fetal growth is slow during the first 2/3rds so there’s not as high of an energy requirement for the mother
What are the 4 functions of the 4 placental mebranes?
1.Protection of developing embryo and fetus
2.Nutrition
3.Respiration
4.Hormone production
Pregnancy recognition signal in ruminants
Interferon tau
Pregnancy recognition signal in swine
Estrogen
Pregnancy recognition signal of mice
Prolactin
Pregnancy recognition signal of humans
Chorionic gonadotropin
Pregnancy recognition signal in horses
Unknown; possibly movement of the embryo for the first 18 days of pregnancy
Which type of placenta is most efficient?
Discoid; only 3 layers of tissue to connect placental blood to maternal
What is the least efficient type of placenta?
Cotyledonary; 6 layers between fetal and maternal blood supply
Maternal side of placenta in pigs
Rugae
Fetal side of placenta in pigs
Areola
Fetal side of placenta in cows
Cotyledon
Maternal side of placenta in cows
Caruncle
Species examples with diffuse placentas
Horses and pigs
Species examples with cotlyedonary placenta
Cows, sheep, goats (ruminants)
Species examples with zonary placenta
Cats (carnivores)
Species examples with discoid placenta
Primates and rodents
What are the stages of embryonic development? (from ovum to blastocyst?)
ovum -> fertilization -> 1-cell ->2-cell -> 4-cell -> 8-cell -> 16-cell -> morula -> blastocyst
A signal that varies among species that will prevent the production of PGF2a so that pregnancy will continue
Maternal recognition of pregnancy
What species is an exception to the placental function of hormone production regarding P4
swine
Endotheliochorial, 5 layers of tissue between fetal and maternal blood supply
zonary
Where fetus connects with maternal
placentomes
What does hemochorial mean?
placenta sits in the maternal blood
