PLACENTAL DISSECTION

The word placenta comes from the Latin word for cake.

HISTORY OF PLACENTA: One of the first China, Li Shi-Zhen, 1578. Traditional Chinese Medicine (TCM) techniques.

What is placenta ? Human placenta is a discoid, fetal maternal organ which connects the foetus with the uterine wall of the mother.

Structure of the placenta

Human placenta develops from two sources the placenta has two components:• (A)FETAL PORTION:Formed by the chorion

frondosum-Its developing from blastocyte to fetus.

• (B)MATERNAL PORTION: Formed by the decidua basalis - After the implantation of the embryo, to uterine endometrium is called the decidua.

PARTS OF PLACENTA1.MATERNAL PLACENTA(desidua): Decidua is the term for the uterine lining (endometrium) during a pregnancy

2. FETAL PLACENTA:• Umbilical cord tissue-Cord tissue contains blood vessels

supported by tissue called Wharton's jelly, which is a rich source of mesenchymal stem cells (MSCs).

• Chorionic plate-that portion of the chorionic wall in the region of its uterine attachment, which gives rise to chorionic villi.

• chorionic villi-chorion to provide maximum contact area with maternal blood.

Placenta - Gross Anatomy

• Fleshy• Weight-500-600 gm• Diameter- 15-20 cm• Thickness-2.5-3 cm• Spongy to feel• Two surfaces- Maternal and fetal

Placental barrier or membrane

Maternal and fetal blood are separated by placental membrane or barrier (0.025 mm thick )

5. Umbilical cord tissue

COLLECTING UMBILICAL CORD TISSUE The umbilical cord should be sampled from the fetal end of the cord remaining on the placenta after delivery. Avoid sections of the umbilical cord that were previously clamped or sustained needle punctures.

Dissection of the Chorionic Plate (CP) Tissue:

• Mechanically remove of the amniotic membrane from the fetal surface of the placenta.

• Cut pieces ~1 cm wide by 0.5 cm deep from the chorionic plate. Harvest the chorionic plate from the region nearest to the umbilical cord, away from the edge of the placenta.

Dissection of the Chorionic Villi (CV) Tissue: Dissect CV tissue 0.5-1 cm deep from placental tissue where the CP has already been removed. Again, harvest CV from theregion closest to the umbilical cord, away from the edge of the placenta. Try to stay at least 1 cm away from the maternal side of

the placenta (containing decidua basalis tissue)

DECIDUAL (D) TISSUE COLLECTION Cut pieces of 0.5 cm thickness from the maternal side of the placenta (containing decidua basalis tissue).

Site A

Site B

SAMPLE COLLECTION ZONAL

•pre-labelled 5 mL tubes, with ~3 ml of RNAlater or buffer with antibiotics.•Store all samples at 4ºC before shipping to processing Lab.