Question

The placental barrier between the maternal and foetal blood is minimum in
A. Goat
B. Pig
C. Cow
D. Human

Answer 1

The placenta is an organ which during pregnancy, develops in the uterus. This structure supplies the developing baby with nutrients and oxygen. It is connected to the baby via the umbilical cord.

Complete answer:
The six-layer placenta is known as the epithelio-chorial placenta. It is the primitive type that is present in marsupials, lemurs, horses, cows, etc.
It consists of six layers:
1. Maternal blood vessel endothelium
2. Endometrial connective tissue or mesenchyme.
3. Uterine epithelium
4. Chorionic epithelium
5. Foetal mesenchymal
6. Foetal blood vessel endothelium.

The two halves of the placenta have immediate contact. In the wall of the uterus, the villi of the epithelio-chorial placenta push and lie in pockets-like uterine wall depressions. There are three layers of foetal extraembryonic membrane in the human placenta. It is called the allantoic placenta chorion. Trophoblast uterine epithelium is the outermost foetal membrane; uterine connective tissue and maternal blood vessel endothelium are not present. Humans can only produce one or humans can produce two because of fertilization. More animals can produce more offspring at a time than that. The overall number of barriers found in many mammals is six, but only three barriers are present in human beings.

Therefore,' D-human' is the correct response.

Note: Nearly all mammals have a similar placenta structure and function. The distinction lies in the gross form of the placenta and the distribution between the foetal membrane and the endometrium of the touch sites. There is also a small variation in the amount of tissues between the maternal and foetal vascular systems.