Question

The number of foetal membranes in humans is?
A. 2
B. 3
C. 4
D. 1

Answer 1

Hint: Fetus is the developing unborn child which is formed by successive division of the diploid zygote after fertilization of male and female Haploid gametes in the fallopian tube of the female reproductive system.

Complete answer:
Foetus is present in the four foetal membrane and the foetus is attached to the wall of the uterus via placenta which arises from one of the foetal membranes, this placenta provide all nutrition which is necessary for fetus development and remove out all excrete which is created by the foetus.

The four number of the fetal membrane is present, which are collectively knowns extraembryonic membrane:
• Chorion: It is made up of trophoblast from outside and inside its made up of somatopleuric extraembryonic mesoderm. It forms a placenta which is attached to the uterus.

• Amnion: It is made up of trophoblast from inside and outside somatopleuric extraembryonic mesoderm. The space is present in between the embryo and amnion called an amniotic cavity, which is filled with clear fluid secreted by the embryo and its membrane called amniotic fluid; this fluid acts as a protective barrier against shock and desiccation.

• Allantois: It is the third embryonic membrane, which is made up of endoderm inside and splanchnopleuric extraembryonic mesoderm from outside, it appears as sac-like that arises from the gut of the embryo near the yolk sac. It is small and burns blood vessels to the placenta in humans.

• Yolk sac: The primary yolk sac consists of splanchnopleuric extraembryonic mesoderm outside and from inside endoderm. It is non-functional in human beings but acts as site early blood cell formation.

Hence, the correct answer is option (C).

Note: The fetal membrane present around the fetus from the gestational period which ensures the maintenance of pregnancy to delivery. The trophoblast cell gives rise to the mass of cells called extraembryonic mesoderm.