Question

Match List-I with List-II: 

List-I	List-II
(A) Epitheliochoreal placenta	(I) Carnivores
(B) Synepitheliochoreal placenta	(II) Primates
(C) Endotheliochoreal placenta	(III) Horse and pig
(D) Hemochoreal placenta	(IV) Sheep and goat

Choose the correct answer from the options given below:

• (A) - (II), (B) - (IV), (C) - (I), (D) - (III)
• (A) - (II), (B) - (IV), (C) - (III), (D) - (I)
• (A) - (IV), (B) - (I), (C) - (IV), (D) - (III)
• (A) - (III), (B) - (IV), (C) - (I), (D) - (II)

Hint:

To remember placental barriers (from thickest to thinnest):
- Epitheliochoreal: Horse, Pig (6 layers)
- Synepitheliochoreal: Ruminants (modified 6 layers)
- Endotheliochoreal: Dogs, Cats (4 layers)
- Hemochoreal: Humans, Primates, Rodents (3 layers)

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Placentas are classified histologically based on the number of tissue layers separating the maternal and fetal bloodstreams.
There are six potential tissue layers (three maternal and three fetal).

Step 2: Detailed Explanation:
Let us match each histological type of placenta with its representative animal species:
- (A) Epitheliochoreal Placenta: All six tissue layers remain intact.
The chorionic epithelium of the fetus is in direct contact with the intact uterine endometrial epithelium.
This type is found in the horse and pig (III). Thus, (A) matches with (III).
- (B) Synepitheliochoreal Placenta: A modified epitheliochoreal placenta where binucleate giant cells from the chorion migrate and fuse with maternal endometrial cells.
This type is characteristic of ruminants like the sheep and goat (IV). Thus, (B) matches with (IV).
- (C) Endotheliochoreal Placenta: The maternal epithelium and connective tissue are lost.
The chorionic epithelium is in direct contact with the endothelial lining of maternal blood vessels.
This four-layer barrier is found in carnivores like dogs and cats (I). Thus, (C) matches with (I).
- (D) Hemochoreal Placenta: All maternal tissue layers are lost.
The fetal chorionic epithelium is in direct contact with maternal blood.
This three-layer barrier is found in primates and rodents (II). Thus, (D) matches with (II).
This matching sequence gives: (A) - (III), (B) - (IV), (C) - (I), (D) - (II).

Step 3: Final Answer:
The correct match is (A) - (III), (B) - (IV), (C) - (I), (D) - (II).