IGCSE Biology Paper-4: Specimen Questions with Answers 262 - 263 of 279

Passage

The diagram shows a human egg cell and a human sperm cell.

Human Egg Cell and Sperm Cell

Question 262 (1 of 6 Based on Passage)

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Three hormones that control the menstrual cycle are:

  • follicle stimulating hormone (FSH)
  • luteinizing hormone (LH)
  • oestrogen.

Describe the role of oestrogen in controlling the menstrual cycle.

Explanation

Oestrogen secretion, though continues throughout the reproductive period of females, but its amount increases slightly before the mid of each menstrual cycle. The rising level of oestrogen causes the thickening of endometrium of uterus. This lining of uterus is richly supplied with the blood vessels and endometrial glands. Increasing amount of oestrogen, by feedback mechanism, inhibits the secretion of FSH and gonadotropin releasing hormone. Breast development at the time of puberty is also under the influence of oestrogen.

Egg Released

Question 263 (2 of 6 Based on Passage)

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Artificial insemination is sometimes used as a treatment for female infertility. Outline how artificial insemination is carried out in humans.

Explanation

The main peculiarity of the artificial insemination is that the sperm is inserted with all-natural fluids and other cells ejaculated with sperm. This form of artificial insemination includes the insertion of sperm into the woman՚s cervix. To succeed in artificial insemination, the following steps will be followed:

  • The woman will need to watch her ovulation cycle. A medical professional may administer medications to cause the woman to ovulate and increase her chances of releasing eggs.
  • The doctor will insert the sperm from the donor the woman or couple has previously chosen. The harvesting of sperm in the following ways: Masturbation, Direct removal from the man՚s reproductive system.
  • After the sperm reaches proper temperature, it is inserted into the woman՚s cervix using a specialized syringe.
  • After the insertion, the woman should remain lying for between 15 and 30 minutes to facilitate the smooth flow of the sperm into the uterus. Afterwards, she can resume her normal daily duties.
Injected and Washed Sperm

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