Embryology: fertilisation and implantation: practice question

A Anatomy question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Anatomy · Embryology: fertilisation and implantation

Sample item

A woman with scarring from previous pelvic inflammatory disease is counselled about her risk of ectopic pregnancy. Where does fertilisation normally occur, and when does implantation of the blastocyst begin?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. In the ampulla of the uterine tube, with implantation beginning about 6 to 7 days after fertilisation

Fertilisation normally takes place in the ampulla of the uterine tube. The zygote cleaves while travelling to the uterus and the blastocyst starts implanting in the endometrium around day 6 to 7. Damage to tubal cilia or the lumen delays transport and raises the risk of implantation in the tube.

Option by option

  • A. In the ampulla of the uterine tube, with implantation beginning about 6 to 7 days after fertilisation (correct)

    Correct. The ampulla is the usual site, and implantation begins at about day 6 to 7.

  • B. In the uterine cavity, with implantation beginning at 14 days after fertilisation

    Fertilisation does not take place in the uterine cavity, and implantation begins earlier than day 14.

  • C. In the isthmus of the uterine tube, with implantation beginning about 2 days after fertilisation

    The isthmus is not the usual site of fertilisation, and implantation at day 2 is far too early.

  • D. In the infundibulum, with implantation completed on the third day

    The infundibulum is the funnel-shaped opening, and implantation is not complete at day 3.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Anatomy questions

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is A, In the ampulla of the uterine tube, with implantation beginning about 6 to 7 days after fertilisation. Fertilisation normally takes place in the ampulla of the uterine tube.

Why is "In the uterine cavity, with implantation beginning at 14 days after f…" not the answer?

Fertilisation does not take place in the uterine cavity, and implantation begins earlier than day 14.

Why is "In the isthmus of the uterine tube, with implantation beginning about…" not the answer?

The isthmus is not the usual site of fertilisation, and implantation at day 2 is far too early.

Why is "In the infundibulum, with implantation completed on the third day" not the answer?

The infundibulum is the funnel-shaped opening, and implantation is not complete at day 3.

What concept does this question test?

It tests Embryology: fertilisation and implantation in Anatomy. The zygote cleaves while travelling to the uterus and the blastocyst starts implanting in the endometrium around day 6 to 7. Damage to tubal cilia or the lumen delays transport and raises the risk of implantation in the tube.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Embryology: fertilisation and implantation?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.