Placenta

Question 1

source of HGC

Answer 1

syscytiotrophoblast

Question 2

name of spaces in syncytio..

Answer 2

lacuna - fill with maternal blood

Question 3

layer that separates embryo from cytotrophoblast

Answer 3

extra-embryonic mesoderm

Question 4

what separates the extraembryonic mesoderm into parts

Answer 4

extraemb. coelom - chorionic cavity

Question 5

layers of extraembry. mesoderm and their coverings

Answer 5

1. somatic - covers amniotic membrane

2. splanchnic - covers yolk sac

Question 6

layer of uterus that receives the embryo

Answer 6

decidua

Question 7

3 layers of decidua

Answer 7

1. capsularis - overlies implantation site
2. basalis - underlies implantation site
3. parietalis - everything else

Question 8

4 types of villi and their cell sources

Answer 8

1. primary - invading cytotrophblast
2. secondary - extraembry. somatic mesoderm
3. tertiary - filled with blood vessels
4. anchoring - cells spreading from cytotrophoblastic shell

Question 9

product of vessels in connection stalk

Answer 9

umbilical V and A

Question 10

space between villi

Answer 10

intervillous spaces

Question 11

fate of villi by region

Answer 11

1. in capsularis - recede>smooth chorion

2. in basalis - branch>bushy chorion>placenta

Question 12

hydatiform moles

Answer 12

1/1000 - no embryo

Question 13

fate of chronic cavity

Answer 13

amniotic cavity expands until it makes it dissappear

Question 14

fate of uretine cavity

Answer 14

expansion of amnion and embryo until capsularis meets and fuses with parietalis

Question 15

product of villous trees

Answer 15

cotyledons

Question 16

spaces surrounding cotyledons

Answer 16

plancental septae

Question 17

contents of umbilical cord

Answer 17

2 arteries, 1 vein, vitelline duct, whartons jelly

Question 18

types of monozygotic twins and separation stage

Answer 18

diamnitic, monochorionic - split as blastocysts

monoamnion, monochorion - split as epiblast

Question 19

twin transfusion syndrome

Answer 19

anastamoses in fetal circulation in placenta

Question 20

placental pathologies

Answer 20

placenta accreta - deep attachment
praevia - abnormal placement
abruption - separation before labor

Question 21

two major components of placenta and their origins

Answer 21

maternal - decidua basilaris

fetal - villous chorion

Question 22

time to completion of vascular network

Answer 22

4th week

Question 23

what anchors sac to basilis

Answer 23

villi

Question 24

time at which cytotrophoblast breaks down in villi

Answer 24

20 weeks

Question 25

tissues that make up the chorion (3)

Answer 25

extra-embryonic somatic mesoderm, cytothrophoblast, syscytiotrophoblast

Question 26

cells forming the shell of anchoring villi

Answer 26

cytotrophoblast