The menstrual cycle

Hormones are important for controlling many processes in the human body.

Hormones are produced by glands.

Which organ system has glands that produce hormones?

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How are hormones transported around the body?

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Figure 1 shows glands in a woman’s body.

Draw one line from each gland to the name of that gland.

Which gland in Figure 1 produces insulin?

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Which organ does insulin mainly affect?

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Give one effect of insulin.

Some hormones control a woman’s menstrual cycle.

Which hormone causes an egg to mature in the ovary?

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Which two are hormones that help to maintain the lining of the uterus during pregnancy?

Tick (✓) two boxes.

Contraception prevents pregnancy.

Give two methods of contraception that use hormones.

Hormones are important for regulating the menstrual cycle. During the menstrual cycle, eggs mature inside follicles in the ovaries. A 27-year-old woman was infertile. A doctor tested a sample of the woman’s blood. The test did not detect any follicle stimulating hormone (FSH) in the woman’s blood. The doctor gave the woman daily injections of FSH for 7 days. The doctor measured:

• the concentration of FSH in the woman’s blood

• the concentration of oestrogen in the woman’s blood

• the volumes of developing follicles in the ovaries.

Figure 12 shows the results.

Give evidence from Figure 12 that the follicles in the ovaries release oestrogen.

Injection of FSH caused the development of a number of follicles. The mean diameter of the follicles on day 11 was 22 millimetres. Calculate the number of follicles in the woman’s ovaries on day 11. Assume each follicle is a sphere.

r = radius

Give your answer to the nearest whole number.

Before treatment with FSH, the woman had underdeveloped breasts. Explain why the lack of FSH in the woman’s blood caused underdeveloped breasts.

Usually males and females both produce FSH. The woman had inherited a faulty gene for FSH production from each of her parents. The woman’s parents both produce FSH. Show how the woman’s parents could have a child that does not produce FSH. You should:

• draw a Punnett square diagram

• identify the phenotype of each offspring genotype

• use the symbols below: H = allele for making FSH h = allele for not making FSH

The woman continues to have injections of FSH. The woman has a child with a man who is heterozygous for the FSH gene. Explain why the probability that the child will be able to produce FSH is 0.5.

In the human female, an egg is released from one of the ovaries about once every four weeks. During the four weeks, the lining of the uterus thickens and then breaks down. This is called the menstrual cycle.

Which two hormones are female reproductive hormones? Tick (✓) two boxes.

Follicle stimulating hormone (FSH) is another female reproductive hormone. What is the function of FSH in the menstrual cycle? Tick (✓) one box.

Sperm cells can survive inside a woman’s reproductive organs for five days. An egg cell can survive for one day after ovulation. In one woman ovulation occurred on day 14. Give the range of days on which sexual intercourse could result in fertilisation.

If a man and a woman have sexual intercourse and do not want to produce a baby, they may use contraception. Explain how different methods of contraception prevent pregnancy.

Reflex actions are coordinated by the nervous system.

What is meant by the term ‘reflex action’?

A woman’s hand accidentally touches a hot object. The woman moves her hand away rapidly. Describe how the woman’s nervous system coordinates the reflex action.

The endocrine system coordinates many internal functions of the body. Give three ways coordination by the endocrine system is different from coordination by the nervous system.

Describe how hormones control the menstrual cycle.

Figure 6 shows the production of sperm cells in humans.

Cell A is a normal body cell.

How many chromosomes are there in cell A ?

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What is the mass of DNA in cell E ?

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What type of cell division produces sperm cells?

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Sometimes there are errors in copying the genetic material.

What term describes an error in the genetic material?

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A woman has three children, aged 4, 6 and 9 years.

Why are the children not genetically identical?

In sexual reproduction, a sperm cell fuses with an egg cell to form a new single cell.

An embryo develops from the single cell.

The cell divides three times to produce the embryo.

How many cells are there in the embryo after three cell divisions?

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Figure 7 shows a different human embryo.

Measure image length X on Figure 7.

Give your answer in millimetres (mm).

The image in Figure 7 has been magnified 500

Calculate the real length of the embryo.

Use the equation:

Give your answer in micrometres (m).

The embryo may not implant in the lining of the uterus.

The embryo will then be lost from the woman’s body several days later.

Explain why the woman may not notice this has happened.

Figure 2 shows some changes that occur during the menstrual cycle.

Figure 2 shows that the lining of the uterus thickens between days 7 and 27.

What is the purpose of thickening the lining of the uterus?

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Which hormone causes thickening of the lining of the uterus?

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On which day is fertilisation most likely to occur?

Use information from Figure 2.

Table 2 gives information about some different methods of contraception.

A man and a woman decide to use the condom as their method of contraception.

Suggest three reasons for this decision.

Use information from Table 2 and your own knowledge.