Embryology: Comparison Placenta

Front 1

placenta

Back 1

-as a result of implantation, fetal membranes are embedded into the uterine wall and establish contact
- placenta: composite structure formed by close contact of fetal membranes and maternal tissue
- nutrients and oxygen from maternal blood go from uterine artery to umbilical vein
- excretory products go from umbilical artery to uterine vein

Front 2

functions of placenta

Back 2

1. nutrition
2. respiration through gaseous exchange
3. excretion
4. barrier (impermeable to bacteria)
5. synthesis of hormones: estrogen, progesterone, gonadotrophins

Front 3

choriovitelline or yolk sac placenta

Back 3

yolk sac combine with the chorion
- horse and dog in the 1st 1/4, which later regresses
-based on fetal membranes involved

Front 4

chorioallantoic placenta

Back 4

-allantois fuses with the chorion
-most common type in domestic animals: ruminants, pigs, carnivores, equines
-based on fetal membranes involved

Front 5

diffuse placenta

Back 5

-chorionic villi are uniformly distributed over the entire sace
-mare
-sow: further development of the folds of different order increases the surface area for feto-maternal exchange

Front 6

cotyledonary placenta

Back 6

-tufts of the chorionic villi (cotyledons) attach to endometrial prominences (caruncles)
- combined fetal (cotyledon) and maternal (caruncle) structures form placentomes
-ruminants

Front 7

zonary placenta

Back 7

chorionic villi form a band around the chorionic sac
-carnivores

Front 8

discoidal placenta

Back 8

chorionic villi form one or two disc shaped area
-primates, rodents and bats

Front 9

villous placenta

Back 9

simple branching of chorionic villi
-sow, mare and ruminants

Front 10

labyrinthine placenta

Back 10

complicated and anastomotic branching of the chorionic villi
-carnivores and primates

Front 11

deciduate placenta

Back 11

-extensive loss of maternal tissues occurs at the time of parturition due to the complicated interlocking of fetal and maternal tissue
-primates and carnivores

Front 12

nondeciduate placenta

Back 12

little loss of maternal tissue occurs due to a relatively simple feto-maternal contact
-sow, mare, ruminants

Front 13

fetal side layers of placenta

Back 13

1. chorionic (villous) epithelium
2. fetal (villous) CT
3. endothelium of the allantoic blood vessels

Front 14

maternal side layers of placenta

Back 14

1. uterine epithelium
2. uterine CT
3. endothelium of uterine blood vessels

Front 15

epitheliochorial placenta

Back 15

chorionic epithelium is in contact with uterine epithelium
- all 6 layers are present
-sow and mare`

Front 16

syndesmochorial

Back 16

chorionic epithelium is in contact with uterine CT
- 5 layers present
- ruminants

Front 17

endotheliochorial

Back 17

chorionic epithelium is in contact with the endothelium of the uterine blood vessels
-4 layers present
-carnivores

Front 18

hemochorial

Back 18

chorionic epithelium is in contact with the uterine blood
-3 layers present
-primates