The menstrual cycle

The diagram shows the human female reproductive system with some structures labelled.

In which structure does ovulation occur?

Explain the importance of progesterone in the menstrual cycle.

Explain how the placenta enables a developing embryo to obtain nutrients.

For fertilisation to occur, a sperm needs to reach an ovum.

Which of these describes the number of chromosomes in the nucleus of a human sperm?

Scientists are developing a contraceptive drug to reduce fertility. The drug is tested on 25 male mice. Graph 1 shows the effect that different concentrations of the drug have on the mean concentration of sperm in semen. Graph 2 shows the effect that different concentrations of the drug have on the percentage of sperm that can move.

The scientists conclude that the drug could be used as a contraceptive to reduce fertility in humans. Discuss the scientists’ conclusion. Use information in the graphs and your own knowledge to support your answer.

The diagram shows four glands in the human body labelled W, X, Y and Z.

LH is a hormone involved in the menstrual cycle.

Which labelled gland produces LH?

Describe the functions of LH during the menstrual cycle.

The diagram shows a fetus developing in a uterus.

Explain how the amniotic fluid and placenta enable the safe growth of the fetus.

Scientists investigated the effects of tobacco smoking and taking mineral ion supplements on the growth of developing babies during pregnancy.

The scientists looked at four groups of mothers.

• Group A non-smokers taking mineral ion supplements

• Group B non-smokers not taking mineral ion supplements

• Group C smokers taking mineral ion supplements

• Group D smokers not taking mineral ion supplements

The graph shows the mean masses of developing babies at 12 weeks of pregnancy at 24 weeks of pregnancy and at birth (36 weeks).

Calculate the percentage difference at 36 weeks of the mean mass of babies from mothers in group A compared with the mean mass of babies from mothers in group D.

Give your answer to the nearest whole number.

Comment on the effect of smoking and the effect of taking mineral ion supplements on the growth of babies.

Use the graph and your own knowledge to help your answer.

The diagram shows the human female reproductive system.

Where does fertilisation normally occur?

State how oestrogen and progesterone affect structure C during the menstrual cycle.

oestrogen

progesterone

In vitro fertilisation (IVF) is used to help some people have children. Eggs are mixed with sperm in a laboratory. Embryos are then transferred into a uterus.

Describe how an embryo forms after the eggs and sperm have been mixed together.

If more than one embryo is transferred to a uterus, IVF can result in multiple births, such as twins or triplets. Pregnancies that produce more than one baby can be a health risk. In the United Kingdom, since 2007, the recommendations for the number of embryos transferred are

• a person under 40 should have only one embryo placed into their uterus

• a person over 40 may have two embryos placed into their uterus

The graph shows the percentage of IVF treatments that led to multiple births from 1993 to 2019.

The table shows the success rates for IVF in the United Kingdom in 2019 for people of different age groups.

Discuss the effects of limiting the number of embryos transferred. Use the information in the table and the graph to support your answer.

Hormones control the menstrual cycle.

Name the gland that produces FSH.

The diagram shows the changes in four hormones during the human menstrual cycle.

Which line represents the hormone progesterone?

Describe the roles of FSH and LH in the menstrual cycle.

FSH

LH

Reproductive hormones can be used as contraceptives to prevent pregnancy. The table gives information about three different methods of hormonal contraception.

Discuss the advantages and disadvantages of the three methods of contraception shown in the table.

The diagram shows part of the female reproductive system with some structures labelled.

Name the structures labelled A, B and C.

Describe the role of structure D in reproduction.

The graph shows the changes in the levels of hormones released from structure B during one menstrual cycle.

Explain the importance of the changes in hormone M and hormone N during the menstrual cycle.

Other hormones are involved in the menstrual cycle.

Describe the role of one other named hormone in the menstrual cycle.

The diagram shows the human female reproductive system.

Which label shows where ovulation occurs?

Which label shows where fertilisation usually occurs?

The diagram shows the changes in thickness of the uterus lining and levels of two hormones produced by the ovary during a menstrual cycle.

0 days 14 days 28 days

Hormones X and Y are produced by the ovaries.

Name X and Y.

Explain the function of hormone X during the menstrual cycle.

The diagram shows a human fetus developing in the uterus.

Explain how the structure of the placenta enables the efficient exchange of substances between the fetus and the mother.

The hormones FSH and LH are involved in the regulation of the menstrual cycle.

Which row gives the correct source for each hormone?

The graph shows the concentration of LH in the blood of a woman when she is unlikely to become pregnant and when she is likely to become pregnant.

Calculate the percentage increase in concentration of LH in the blood from when the woman is unlikely to become pregnant to when the woman is likely to become pregnant.

Describe the roles of the hormones FSH and LH.

5 (a) The table gives information about some hormones involved in the menstrual cycle. Complete the table by giving the missing information.

State what is meant by the term menstruation.

A girl starts to ovulate at the age of 12 years and continues to ovulate until she reaches the age of 51 years. [Assume her menstrual cycle is 28 days and she releases one egg per cycle.] Estimate the maximum number of eggs she could release in her lifetime. Give your answer to two significant figures.

number of eggs =_........

Give a reason why a female does not produce as many offspring as the number of eggs she releases.

Organs in the human body have different functions.

Name the organ that produces bile.

Which organ releases progesterone?

Which row of the table correctly shows whether the kidneys and skin are involved in excretion?

The stomach is an organ found in the alimentary canal.

Describe the role of the stomach.