Sexual Reproduction in Humans

Identify the letter on Fig. 1.1 that has been used to label the area where each of the following happens:

where sperm is deposited ______

where oestrogen is produced ______

where implantation occurs. ______

Some women can have blockages in the tubes labelled B.

Explain why this would prevent them becoming pregnant.

In step 1, the patient is injected with a hormone.

Name a hormone that could be used.

______

In step 2, a drug is used to stop the action of luteinising hormone (LH).

Explain why it is important to stop the action of LH.

When a man and a woman are unable to have children, they are said to be an infertile couple.

There are estimated to be 90 million infertile couples in the world.

There are many causes of infertility but 17% of cases are due to blocked tubes in women.

Calculate the number of couples in the world whose infertility is due to blocked tubes in women.

Give your answer in standard form.

number of couples = ______

The study shows a probability of 20% that sexual intercourse three days before ovulation will result in pregnancy.

State how many times more likely pregnancy is if sexual intercourse takes place two days later.

______

Explain the role of named hormones in the menstrual cycle during the days investigated by this study.

The diagram shows a fetus developing in the uterus of a pregnant female human.

Name structure X and describe the functions of this structure.

name = ______
functions = ______

Describe the process of fertilisation and the early development of a ball of cells.

The ball of cells may then become implanted in the wall of the uterus and form a developing fetus.

Describe how a developing fetus obtains and uses the named substances it needs and removes its named waste products.

Describe the role of each of the following hormones in the menstrual cycle:

FSH, ______

progesterone. ______

Suggest why pregnancy may occur if sexual intercourse takes place several days before ovulation.

Name the method of birth control that makes use of the information in a chart like this. Explain how this method of birth control is used to prevent pregnancy.

name of method ______

explanation ______

Suggest why the method of birth control that you have named in (b)(ii) is considered to be unreliable.

Describe how syphilis is transmitted.

Describe the symptoms, signs and effects of syphilis.

Describe the treatment of syphilis and suggest why it is not possible to treat the infection that leads to AIDS in the same way.

Use Fig. 4.1 to state the time at which each of the following occurs:

the uterus lining reaches maximum thickness

______

the concentration of progesterone begins to increase.

______

Draw a ring around the day from Fig. 4.1 on which ovulation is most likely to occur.

$\text{day } 0 \qquad \text{day } 7 \qquad \text{day } 14 \qquad \text{day } 21 \qquad \text{day } 28$

Explain how it can be concluded from Fig. 4.1 that the person did not become pregnant during the 28 days shown, even though ovulation occurred.

The menstrual cycle is controlled by hormones. Name two hormones, other than progesterone, that control the menstrual cycle. State one role of each hormone.

name of hormone

______

role in the menstrual cycle

______

name of hormone

______

role in the menstrual cycle

______

Complete Table 4.1, stating the names of the structures in Fig. 4.1(a) and indicating whether they carry urine and/or sperms using yes or no as appropriate.

Table 4.1

Indicate by drawing a line across each of the relevant parts in both Fig 4.1(a) and 4.1(b), where a cut may be made in order to carry out a form of surgical contraception.

In older men, the prostate gland tends to increase in size. Suggest an explanation for how this may affect urination.

Name one secondary sexual characteristic in males.

______

Name the hormone responsible for the development of secondary sexual characteristics in males.

______

Name the organs that produce this hormone.

______

Name the hormones F and G.

F ______

G ______

State what occurs at time H.

______

Fig. 3.2 shows the thickness of the same woman's uterus lining over a 4-week period.

The graph shown in Fig. 3.1 does not begin at the same time as the cycle shown in Fig. 3.2.

Indicate on Fig. 3.2, with a line labelled J, the stage shown by line H on Fig. 3.1, and explain your reason for choosing this point on the graph.

FSH is given during fertility treatment to women who experience problems becoming pregnant.

Progesterone is a component of the contraceptive pill.

With reference to named substances, describe the functions of the placenta and the umbilical cord.

State one similarity and one difference in the functions of the urethra in a male and in a female adult person.

similarity ______

difference ______

State the differences between male and female human gametes in terms of size, numbers and mobility.

Describe the advantages and disadvantages of surgical methods of birth control.

advantages ______

disadvantages ______