Placentation

Question 1

Define: syndesmochorial

Answer 1

endometrial epithelium transiently erodes and then regrows, causing intermittent exposure of the maternal capillaries to the chorionic epithelium

Question 2

Epitheliochorial vs. Endotheliochorial vs Hemochorial

Answer 2

Epitheliochorial: binucleate giant cells
that originate from trophoblast cells and migrate from the chorionic epithelium and invade the endometrial epithelium. lactogen and pregnancy specific protein B,
• Layers:(6)
- Chorionic capillaries(Endo)
- Chorionic interstitium (basement) 
- Chorionic epithelium (epi)
- Endometrial epithelium(epi)
- Endometrial interstitium(basement)
- Endometrial capillaries(endo)

Endotheliochorial:(5)
Maternal endometrial epithelium is completely
eroded, interstitium somewhat eroded. exposes maternal capillaries ->epithelial cells of chorion. 
• Layers:
– Chorionic capillaries(Endo)
– Chorionic interstitium(basement) 
– Chorionic epithelium(epi)
– Endometrial interstitium (basement)
– Endometrial capillaries(endo)

Hemochorial (Human)
Chorionic epithelium is in direct contact with
maternal pools of blood. epithelium, intersititium
and capillary walls eroded.

• Layers:
– Chorionic capillaries
– Chorionic interstitium
– Chorionic epithelium
–Maternal blood contact

Question 3

Define: allograft and its importance

Answer 3

allograft is the tissue from fetus to maternal that separates fetus from mother and is not immune rejected.

Question 4

Functions of placenta

Answer 4

1. Respiration – gas exchange
2. Nutrients – nutrient delivery
3. Waste disposal – metabolic waste
4. Protection – buffers fetus, lubricates birth canal
5. Endocrine – hormone production
6. Maintains fetal allograft – allograft is a graft of tissue
   from 1 individual to another in the same species , this
   separates fetus from maternal system, trophoblast not
   rejected
7. Regulates transport of substances from mother to
   fetus - Immunoglobulin transfer

Question 5

(ruminants), consumption of

colostrum (mother’s first milk)… bc

Answer 5

They contain epithelialchorial placental(6).
Therefore, essential as it contains large amounts of antibodies that offspring can absorb by pinocytosis in GI
tract for first 24 hours. others use diffusion through maternal blood. sometimes with worms too (endo)