34 Placenta

Question 1

Maternal component of placenta =

Answer 1

DECIDUA = new name stratum functionalis of endometrium
– shed at birth

Question 2

Functional portion of maternal placenta =

Answer 2

Decidua Basalis

Question 3

Fetal portion of placenta =

Answer 3

CHORION – from trophoblast and its two layers (cryptoblast/syncytiotrophoblast) with some extraembryonic mesoderm

Question 4

Functional portion of fetal placenta =

Answer 4

Villous Chorion

Question 5

At implantation the TROPHOBLAST invades endometrium and differentiates into two layers

Answer 5

CYTOtrophoblast and SYNCTIOtrophoblast

Question 6

This layer is dervived from the cytotrophoblast and secretes HCG
Is the layer thats in Direct contact with maternal blood

Answer 6

SYNCTIOtrophoblast

Question 7

this structure projects into lacuna with maternal blood – day 13

Answer 7

CHORIONIC VILLI – primary villi

Question 8

Days 19-20 the cytotrophoblast forms an outer shell attached to the uterus. Maternal blood pierces the shell to flow in and out of _____

Answer 8

intervillous spaces = former lacunae

Question 9

This forms when the mesenchyme (CT) enters the core of the villi

Answer 9

Secondary Villi

Question 10

when fetal capillaries form in the mesenchyme of the villi, they become

Answer 10

Tertiary Villi

Question 11

When does the heart begin to beat/uteroplacental circulation becomes functional

Answer 11

4th Week

Question 12

how does highly oxygenated blood return to the fetus from the placental

Answer 12

via the UMBILICAL VEIN

Question 13

poorly oxygenated blood is sent from the fetus back to the placenta via

Answer 13

umbilical arteries

Question 14

highly oxygenated blood enters the intervillous spaces from endometrial arteries into what space in the endometrium

Answer 14

Decidua basalis

Question 15

how does poorly oxygenated blood in the intervillous space exit the placcenta

Answer 15

Via the endometrial veins

Question 16

What prevents maternal blood from mixing directly with fetal blood

Answer 16

Placental Barrier

Question 17

gestational trophoblastic disease – rare tumors derived from uncontrolled trophoblast cells
most common are benign =

Answer 17

HYADTIDIFORM MOLES
pregnancies without an embryo

Question 18

two eggs are ovulated by and fertilized by TWO different sperm forming two zygotes

Answer 18

DIZYGOTIC = fraternal twins

Question 19

ONE egg is fertilized by ONE sperm forming ONe zygote which later splits into two embryos

Answer 19

MONOZYGOTIC = identical twins

Question 20

if zygote splits at 2 cell stage through morula stage

Answer 20

DICHORIONIC/Diamniotic – each embryo will have its own amnion and chorion

Question 21

if zygote splits at blastocyst stage –>

Answer 21

Monochroionic/Diamniotic = 2 seperate amnions and one chorion

Question 22

if the zygote splits after implantation when the bilaminar disc and amnion have formed

Answer 22

MONOchorionic and MONOamniotic

Question 23

if the embryo splits during or after the primitive streak has formed –>

Answer 23

then the embryos will only partially separate leading to conjoined twins with a shared amnion and chorion – rare