Placenta- Shaw

Question 1

What 2 cells types make up the trophoblast?

Answer 1

Cytotrophoblast

Syncytiotrophoblast

Question 2

Cytotrophoblast

Answer 2

Inner Layer of chorionic villi

Proliferate

Question 3

When do trophoblast cells become cytotrophoblast cells?

Answer 3

After attachment to the endometrium!

Question 4

In what phase of the uterine cycle does implantation occur?

Answer 4

During the secretory phase

Question 5

Describe Syncytiotrophoblast cells

Answer 5

Outer layer of chorionic villi
Don’t have boundaries
Multinucleated
Secrete hCG

**Lack MHCI expression to decrease chance of attack by maternal immune system

Question 6

Primary Villi

Answer 6

Trophoblast only (syncytiotrophoblast outside and cytotrophoblast inside)

**No extraembryonic mesoderm or blood vessels yet

Question 7

Secondary Villi

Answer 7

Mesodermal ingrowth into core of primary villus

Branching occurs

Question 8

Tertiary Villi

Answer 8

Differentiation of blood vessels in the mesodermal core of secondary villus

*Anastomosis of villar blood vessels with fetal circulation

Question 9

Describe an anchoring villus

Answer 9

Tertiary Villi
Cytotrophoblast has grown outside of syncytiotrophoblast to form a cytotrophoblastic shell

**Cytotrophoblast makes direct contact with decidual cells in endometrial stroma

Question 10

What is the decidual reaction?

Answer 10

Transformation of endometrial stromal cells

• Swell due to glycogen and lipid accumulation
• Transformation spreads through out superficial layers of endometrium

Question 11

What are the 3 placental components?

Answer 11

Decidua basalis
Decidua capsularis
Decidua parietalis

Question 12

What constitutes the maternal portion of the placenta?

Answer 12

Decidua basalis

*site of decidual reaction and most extensive villar invastion

Question 13

Decidua capsularis

Answer 13

Layer of placent between conceptus and uterine lumen

*becomes attenuated ast the embryo grows and eventually regresses

Question 14

Decidua parietalis

Answer 14

Remainder of endometrium not occupied by decidua basalis

Question 15

Cotyledons

Answer 15

Adjacent to decidua basalis

Placenta divided into 15-30 lobules by septae from decidua basalis

Question 16

How many tertiary villi are within a cotyledon?

Answer 16

2-4 and their branches

Question 17

What happens to the placental barrier as pregnancy progresses?

Answer 17

Gets thinner!

Question 18

What forms the cotyledons of the placenta?

Answer 18

Decidua Basalis

Question 19

TORCH Infections

Answer 19

Toxoplasmosis
other infections (Parvo B19)
Rubella
CMV
Herpes/HIV
e
Syphillis

Question 20

What placenta cells secrete hCG?

Answer 20

Syncytiotrophoblasts

*helps maintain corpus luteum and its production of progesterone and estrogen

Question 21

What do the synctiotrophoblasts secrete? 4 things…

Answer 21

• hCG
• Progesterone (at 12 wks)
• Human placental lactogen
• Converts androgens produced by fetal adrenal glands to estrogen

Question 22

What 3 things are produced by the decidua basalis?

Answer 22

Prolactin
Prostaglandins
Relaxin

Question 23

Relaxin is secreted by the decidua basalis… what does it do?

Answer 23

Softens pubic symphysis prior to parturition