Question

Which of the following statements is not true about trophoblast?

• A. It is involved in providing nutrition to the developing embryo.
• B. It is involved in the formation of placenta.
• C. It is involved in the formation of extra embryonic membranes such as chorion.
• D. It is involved in the direct formation of embryo.

Answer 1

The correct option is D It is involved in the direct formation of embryo.

Trophoblast forms the outer layer of cells in a blastocyst. It helps in the implantation of the blastocyst. The trophoblast gets attached to the endometrial lining of the uterus. Following this, the endometrial cells multiply rapidly and engulf the entire blastocyst. Hence the blastocyst gets embedded in the endometrium of the uterus.

After implantation, the trophoblast gives rise to chorionic villi that comes in contact with the blood vessels of the endometrium. The cells developing from trophoblast will also have foetal blood vessels. This way the maternal and foetal blood vessels come in contact with each other and form the placenta.

The placenta is the structure through which the nutrients, respiratory gases and metabolic wastes are exchanged between the fetus and the mother. Hence, we can say that the trophoblast is involved in providing nutrition to the growing embryo. It is also involved in the formation of placenta and other extra embryonic membranes such as chorion.

Trophoblast is not directlty involved in the formation of embryo. The inner cell mass is involved in the formation of embryo.