Biology and Health Sciences

Key unit competence To be able to analyse the process of reproduction, pregnancy and childbirth.

Cross-cutting issue Comprehensive sexuality education: Unintended pregnancies and teenage pregnancies may lead to health problems as well as social and economic difficulties. Healthy pregnancies, childbirth, antenatal and postnatal care are essential for all Rwandan women.

At the end of this unit, you should be able to: 

• Describe male and female reproductive systems 

• Explain the process of fertilisation 

• Explain how a pregnancy occurs 

• Describe the signs of pregnancy, and the stages of foetal development and childbirth 

• Define maternal mortality and list major causes of maternal mortality 

• Describe ways that poverty and gender inequality lead to death among pregnant women and how these outcomes can be prevented

 • List health risks associated with early pregnancy and birth 

• Analyse using simulations of stages of pregnancy and discuss the signs and behavioural symptoms of pregnancy 

• Appreciate the importance of the steps that should be taken to promote safe pregnancy and childbirth 

• Show concern about maternal mortality as an issue in the region.

Oral activity In groups, discuss these questions.

 1. Name two main functions of the human reproductive system. 

2. During which time in a woman’s menstrual cycle is she most likely to fall pregnant after unprotected sex? 

3. Discuss how unintended pregnancy can occur.

4. What are the consequences of unintended pregnancies?

The male and female reproductive systems 

In unit 12 you learnt about the male and female reproductive organs and how they are involved in reproduction. Reproduction is the production of offspring or new individuals from their parents. Human reproduction is sexual reproduction, as it requires sex cells, or gametes, from male and female parents. The gametes fuse, or join, to form a new cell. A new organism develops from this cell. The reproductive organs are important for two reasons: they play a role in sexual intercourse and, in females, they provide a place for a new baby to develop. You will find out about these two roles in this unit.

Exercise 14.1 1. 

List the parts of the male reproductive system in which: 

a) sperm are produced 

b) semen leaves the male body. 

2. Write down the pathway of an ovum from the time it is released until it leaves the female body.

 3. In which part of the female reproductive system do the following take place? 

a) fertilisation 

b) development of the foetus

Sexual intercourse

 The male sex cells, or sperm, are produced in the testes of the male reproductive system. 

So the sperm need to be transferred to the inside of the female body to enable one of them to fuse with the ovum. This takes place during sexual intercourse. Sexual arousal occurs when a man and a woman interact and their senses are stimulated. The pulse rate, breathing rate and blood pressure increases. The male penis fills with blood and becomes erect. 

The external female reproductive parts become sensitive to touch and the vagina secretes mucus for lubrication during intercourse. T

he erect penis is placed inside the vagina. In the male, the movement of the penis inside the vagina stimulates a reflex and causes ejaculation.

This is a rhythmic muscular contraction of the male reproductive system from the testes to the penis. It results in the release of semen from the urethra. Male orgasm happens at the same time as ejaculation.

 In the female, the to and fro movement of the penis also leads to orgasm. An orgasm is the peak of sexual arousal and is a combination of pleasurable physical and emotional sensations.

Fertilisation 

During sexual intercourse, the male ejaculates between two and six millilitres of semen that contains about 300 million sperm. Semen is deposited inside the female vagina near the cervix. Sperm in the semen swim upwards into the oviducts. 

If an ovum is in an oviduct, the sperm can reach it within five minutes. The ovum is surrounded by a tough outer coat that makes it difficult for the sperm to penetrate into the ovum. After a few minutes, the strongest sperm passes through the coat around the ovum and attaches to the membrane. Only the head of the sperm penetrates the ovum; the tail stays outside. The nuclei of the ovum and the sperm fuse; this is called fertilisation. The fertilisation event is called conception – a new human being has been created. The new cell that forms after fertilisation is called a zygote.

Foetal development 

After fertilisation, the zygote continues to divide. It divides into two cells, then four, then eight, and so on. Eventually a ball of cells is formed. After about seven days, it develops into a fluid-filled cavity surrounded by a single layer of cells. The cilia move the ball of cells down the oviduct towards the uterus. After about ten days, the ball of cells burrows into the wall of the uterus. This process is called implantation. There it continues to divide into more specialised cells and an embryo is formed. From the eighth week until birth (around 40 weeks), the developing organism is called a foetus.