placenta - new born

Question 1

what is present on the fetal side?

Answer 1

chorionic plate from which the chorionic villi arise from

Question 2

what covers the outer surface on the fetal side?

Answer 2

low cuboidal/ squamous cells of the amniotic epithelium

Question 3

what can be observed beneath the amnion

Answer 3

conn. tissue layer, in which the imbilical vessels are carried

Question 4

where does the conn. tissue layer under the amnion come from?

Answer 4

• extraembryonic mesoderm covering the amnion(amnionic mesdoderm)
• extraembryonic mesoderm covering the trophoblast (trophoblastic mesoderm)

Question 5

what is the chorionic plate covered by?

Answer 5

cytrophoblastic and syncytial layers

Question 6

what attaches to the plate? and what does it contain?

Answer 6

villous stem, contains a trunk from which arise a second and third order branches.

Question 7

what happens to the latter branches?

Answer 7

remain attached to their maternal end to the trophoblastic shell (anchoring villi)

Question 8

what are free or true villi?

Answer 8

outgrowing from the sides of the trunk and the secondary and third order branches

Question 9

what is among the villi, and what is it’s function and what is it lined by?

Answer 9

intervillious space, circulates maternal blood, and lined by syncytial trophoblast

Question 10

what happens in the second half of preganancy?

Answer 10

• cytrophoblast reduces

- syncytiotrophoblast contacts the basement mem.and becomes thinner

Question 11

what is the maternal part of the placenta called? and what lines it?

Answer 11

decidua basalis or basal plate, trophoblast shell lines it

Question 12

why are there opening in the basal plate into the intervillous space?

Answer 12

so the coiled arteries empty the oxygenated blood

Question 13

the placental septa

Answer 13

• extends from the basal plate, and does not reach the chorionic plate
• composed of decidual cells covered by synctial and cytrophoblastic layers

Question 14

what can be found between the syncytiotrophoblast and the maternal tissues?

Answer 14

a layer of eosinophilic fibrinoid

Question 15

where is the placental barrier located, and what are the structures it contains

Answer 15

• between the maternal and fetal blood
• syncytiotrophoblast
• lamina basalis of the syncytiotrophoblast
• mesoderm of the villus
• lamina basalis of the endothel
• capillary endothel

Question 16

where do the capillaries lie?

Answer 16

next to the wall of the chorionic villus