NEET2010ZoologyHuman ReproductionActual
In human female, the blastocyst
Options
- Aforms placenta even before implantation
- Bgets implanted into uterus three days after ovulation
- Cgets nutrition from uterine endometrial secretion only after implantation
- Dgets implanted in endometrium by the trophoblast cells
Correct answer
D. gets implanted in endometrium by the trophoblast cells
Step-by-step solution
Implantation is the attachment of blastocyst to the uterine wall (endometrium). It occurs after 6-7 days of fertilization. During implantation, the trophoectoderm (trophoblast) comes in contact with the endometrium of the uterus and sinks into a pit formed in the endometrium and get completely burried in the endometrium. Trophoblast cells form specialized structures called villi, which help in absorption of nutrient materials.