Implantation and placentation

Question 1

how is a placenta formed?

Answer 1

when foetal membranes become closely attached to the uterine wall to facilitate physiological exchange of gases, nutrients and waste products

Question 2

Label this developing foetus

Answer 2

Question 3

Label the uterine wall

Answer 3

Question 4

Label the uterine wall

Answer 4

Question 5

What are the 3 stages of implantation?

Answer 5

Question 6

What is the function of MUC1 in implantation?

Answer 6

MUC1 = mucin that inhibits attachment of foetus to uterine wall
Uterus prevents implantation except during placentation window

Question 7

Describe invasive vs non-invasive implantation

Answer 7

Non-invasive:
- elongation
- apposition
- attachment
- cows and sheeps (u silly boy its sheep not sheeps)
Invasive:
- apposition
- attachment
- invasion
- primates

Question 8

What the possible tissue layers between foetal and maternal blood circulations?

Answer 8

Question 9

What is an epitheliochorial placenta?

Answer 9

all 6 layers of foetal and maternal tissue
e.g., mare, sow

Question 10

What is an endotheliochorial placenta

Answer 10

4 layers
3 foetal layers
2 maternal tissue layers lost as trophoblast invades uterus
e.g., bitch, queen

Question 11

What is a haemochorial placenta?

Answer 11

3 foetal layers
0 maternal layers
Trophoblasta has invaded into the uterus blood vessels -> pooling of blood against foetal membrane
e.g., rabbits

Question 12

What are chorionic villi?

Answer 12

areas of nutrient exhange - functional units of the placenta

Question 13

What are the types of placenta based in distribution of chorionic villi?

Answer 13

Diffuse: sow, mare
Cotyledonary: cow, ewe
Zonary: bitch, queen
Discoid: human

Question 14

Describe cotyledonary distribution of chorionic villi

Answer 14

Chorionic villi appear in clusters

Question 15

Describe diffuse distribution of chorionic villi

Answer 15

Sow: nutrient exchange across whole surface
Mare: lots of tiny clusters (crypts) across whole membrane

Question 16

Describe the placentation in the sow

Answer 16

Epitheliochorial
Diffuse
Non-deciduate

Question 17

Label the porcine maternal foetal interface

Answer 17

Question 18

Describe placentation in the ewe and sow

Answer 18

Synepitheliochorial placentation
Cotyledonary
Non-deciduate

Question 19

What is a synepitheliochorial placenta in ruminants?

Answer 19

Fusion of BNC to maternal epithelial cell:
- some chorion cells have 2 nuclei (binucleate giant cell/BNC)
- migrates and fuses with maternal cells (gains another nucleus from here)
- empties granule into maternal circulation

Question 20

What is the difference in the placentomes between cows and sheep?

Answer 20

Cow - convex
Sheep - concave

Question 21

What is a placentome?

Answer 21

cotyledons aligned with caruncles

Question 22

Describe placentation in the horse

Answer 22

epitheliochorial placentation
diffuse
non-deciduate

Question 23

What is the chorionic girdle in equine foetuses?

Answer 23

the junction between the 2 types of placenta
Become endometrial cups as foetus develops

Question 24

What is the function of endometrial cups in the equine foetus?

Answer 24

produce eCG
surrounded by immune cells and eventually destroyed

Question 25

Describe placentation in the dog

Answer 25

endotheliochorial placentation Zonary Deciduate

Question 26

Describe the appearance of zonary placenta

Answer 26

Question 27

What is decidualisation?

Answer 27

endometrial stromal cells proliferate and enlarge to become decidual cells decidua = maternal placenta Decidual tissue is important in: - communication between mother and foetus - limits invasion of trophoblast

Question 28

Label the haemochorial placental histology

Answer 28

Question 29

Label the umbilical vasculature

Answer 29