FOETAL MEMBRANE

Question 1

Parts of foetal membrane

Answer 1

AYACCP

Amnion
Yolk sac and stalk
Allantois
Connecting stalk (umbillical cord and vessels)
Chorion
Placenta

Question 2

At 2nd week, blastocyst partially embedded at endometrial stroma

Blastocyst consist of…

Answer 2

Inner cell mass: embryoblast
Outer cell mass: trophoblast

Question 3

Trophoblast consist of…

Answer 3

Cytotrophoblast: inner, mononucleated
Syncytiotrophoblast: outer, multinucleated, noncell boundaries

Question 4

Embryoblast consist of…

Answer 4

Epiblast (above)
Hypoblast (below)

Question 5

In AMNION, what happen in day 8?

Answer 5

• small cavity enlarge become amniotic cavity
  -amnioblast: epiblast adjacent to cytotrophoblast
  -amniotic fluid filled the sac

Question 6

Components of amnion

Answer 6

Clear watery fluid
-carbohydrate
-lipids
-protein
-desquamated cells
-fetal urine

Question 7

Functions of amnion

Answer 7

• external growth
• protection cushion
  -prevent adherence
  -metabolic waste exchange
  -barrier
  -body temperature
  -hydrostatic wedge, cervical canal
  -foetal movement
  -diagnosis disorders

Question 8

What is heuser membrane

Answer 8

-Flatten cells originate from hypoblast form thin membrane

-with hypoblast, it will form primary yolk sac

Question 9

Formation of secondary yolk sac

Answer 9

1. Additional cells from hypoblast migrate inside exocoelemic cavity
2. Proliferate, form new cavity (2nd yolk sac)
3. Smaller than primary, pinched off become exocoelemic cyst

Question 10

Degeneration of yolk sac

Answer 10

CEPHALO CAUDAL + LATERAL FOLDING

-Intraembyonic cavity ➡️ primitive gut
-yolk sac attaches to primitive gut by vitelline duct
- vitelline duct elongate ➡️ umbillical cord
-yolk sac detaches from primitive gut by week 5, degenerate

Question 11

What is allantois

Answer 11

Small diverticulum from posterior yolk sac, extend to connecting stalk

Question 12

Formation of median umbillical ligament

Answer 12

1. Allantois carried fold its extends, urinary bladder ➡️ umbillicus
2. Undergo regression 4-6 weeks ➡️ urachus
3. After birth, urachus ➡️ median umbillical ligament

Question 13

What is primitive umblical ring

Answer 13

Oval line of reflection, between embryo ➡️ embryonic ectoderm

Question 14

Connecting stalk

Answer 14

Consist of allantois and umbilical vessels ( 2 arteries 1 vein)

Question 15

Wharton jelly

Answer 15

Loose connective tissue from umbilical cord, protect umbilical vessels

Question 16

Further development of umbillical cord

Answer 16

1. Embyonic cavity enlarge, expense of chorionic cavity
2. Amnion envelope connecting + yolk sac stalk, ➡️ primitive umbilical cord
3. End of 3rd month, yolk sac shrinks, cavity obliterated
4. Allantois + vitelline duct and vessels obliterate, remnants become umbilical vessels envelope with wharton jelly

Question 17

…… take part in chorionic villi formation

Answer 17

Trophoblast + extraembryonic mesoderm lining cyto trophoblast

Question 18

Types of chorionic villi

Answer 18

1. Primary stem
2. Secondary
3. Tertiary

Question 19

Primary stem villi

Answer 19

Syncytial layer cover cystotrophoblastic core, begin at 3rd week

Question 20

Secondary stem vili

Answer 20

Mesodermal call penetrate core of primary

Question 21

Tertiary

Answer 21

Mesodermal start dy/dx into small blood vessels,➡️ villus capillary system

Question 22

Stem/ anchoring villi

Answer 22

From endometrium of chorionic plate to maternal endometrium

Question 23

Free / terminal villi

Answer 23

Branch from anchoring villi

Exchange oxygen and nutrients

Question 24

Two parts of placenta

Answer 24

1. Foetal : chorion frondosum
   (Trophoblast + extraembryonic mesoderm)
2. Maternl : decidua basilis (functional layer at uterine endometrium)

Question 25

Placenta development at lacunar stage

Answer 25

1. After implantation, blastocyst penetrate deeper into endometrium 2. Vacuoles appeared at syncytiotrophoblast at embryonic pole 3. Vacuoles fuse, large trophoblastic lacunae

Question 26

Uetro placental circulation

Answer 26

Matenal blood enter lacunar spaces

Question 27

How placenta and embryo connected?

Answer 27

1. Capillaries tertiary villi villi contact with (mesoderm + connecting stalk) 2. Vessels establish contact with intraembryonic circulatory system)

Question 28

Placenta berrier before and after 4 months

Answer 28

Before 4 months: EPCS Endothelial foetal capillaries Primary mesoderm Cytotrophoblast Syncytiotrophoblast After 4 months SE Syncytiotrophoblast Endothelial

Question 29

Formation foetal part of placenta

Answer 29

1. Villi cover entire surface chorion 2. At embryonic pole, grow and expend, become chorion frondosum (CF) 3. Villi abembryonic degenerates, CF become foetal part

Question 30

Types of decidua

Answer 30

BCP 1. Basalis: over chorion frondosum 2. Capsularis : over abembryonic pole 3. Parietalis : over uterine wall

Question 31

Contents of decidual cell

Answer 31

1. Abundant lipid and glycogen Tightly connected to chorion in Basalis

Question 32

Structure of placenta

Answer 32

CFMP Cotyledons Foetal surface Maternal surface Peripheral margin

Question 33

Foetal and maternal surface descriptions

Answer 33

Foetal: smooth, covered in amnion, umbilical cord attach at center Maternal: rough, lobulated, 15-20 cotyledons

Question 34

Functions of placenta

Answer 34

1. Exchange gases 2. Exchange nutrients and electrolytes 3. Hormone production 4. Transmission of antibodies

Question 35

Anomalies of placenta

Answer 35

SDAS Site of implantation (increta) Degree of adhesion at uterine wall Attachment at UC Structure and shape (succenturiata)

Question 36

Degree in uterine wall

Answer 36

Accreta : near desidua basilis Increta: myometrium Paccreta: whole thickness uterus

Question 37

Attachment at UC

Answer 37

Velamantous : UC attach at chorionic membrane Bataldore placenta: UC attach at margin