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Question
Trace the events from copulation to zygote formation in a human female.
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Solution
- When coitus (copulation) occurs, the penis releases semen into the vagina (insemination).
- The motile sperms travel quickly past the cervix, penetrate the uterus, and finally reach the fallopian tube's ampullary area.
- The ovary's ovum is also transferred to the ampullary area, where fertilisation occurs.
- Fertilisation can take place only if the ovum and sperms are transferred to the ampullary region at the same time. This is why not all copulations result in fertilisation and pregnancy.
- The process of fusion of a sperm with an ovum is called fertilisation.
- During fertilisation, a sperm comes into contact with the ovum's zona pellucida layer, causing alterations in the membrane that prevent further sperm from entering. As a result, only one sperm can fertilise an ovum.
- The acrosome's secretions aid sperm entry into the cytoplasm of the ovum via the zona pellucida and plasma membrane.
- This causes the secondary oocyte's meiotic division to be completed.
- The second meiotic division is also uneven, producing a second polar body and a haploid ovum (ootid).
- Soon, a diploid zygote is created when the haploid nuclei of the sperm and the ovum fuse together.
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RELATED QUESTIONS
Correct the following statement:
In E. T. techniques, embryos are always transferred into the uterus.
Multiple choice question.
Test tube baby technique is called _______.
Correct the following statement.
Transfering of an embryo with more than 8 blastomeres into the uterus is called GIFT.
In case of a couple where the male is having a very low sperm count, which technique will be suitable for fertilisation?
Artificial insemination means ______.
The first case of IVF-ET technique success, was reported by ______.
In which of the following ARTs, does in vivo fertilisation occur?
Read the given below statements carefully and state whether the following are true (T) or false (F).
- I - MOET is one of the methods of IVF.
- II - ICSI is a method useful only for males who are unable to inseminate.
- III - MTP is considered safe during the first 1 week of pregnancy.
- IV - LNG-20, multi-load 375 are hormone-releasing IUDs.
- V - Steroids inhibit ovulation and implantation.
Choose the correct option regarding the above-given statements.
In which of the following techniques, the embryos are transferred to exist those females who cannot conceive?
Given below are Column A with a list of certain Assisted Reproductive Technologies (ART) and in Column B the procedures followed during ART:
| Column A | Column B | ||
| S. No. | Names of ART | S. No. | Procedures |
| (A) | GIFT | (i) | Transfer of ovum from a donor into the fallopian tube of another female. |
| (B) | ICSI | (ii) | Transfer of semen from the donor into the vagina of the female. |
| (C) | ZIFT | (iii) | Injecting sperm directly into the ovum. |
| (D) | IUI | (iv) | Transfer of early embryos into the fallopian tube. |
Choose the option where ART correctly matches with the procedure.
