What is the reproductive system

What is the reproductive system . Growth is an increase in size e.g. changes from larva to adult.

Development refers to growing gradually and becoming more mature.


This is the process by which all living things multiply and increase in number (become many) i.e. give rise to new off-springs (young ones) to continue a generation of the species.

Types of reproduction

There are two types of reproduction

  1. Asexual reproduction
  2. Sexual reproduction

ASexual reproduction

This is the type of reproduction where no reproductive cells (gametes) are used to produce young ones.

Examples of asexual reproduction

Vegetation propagation in plants e.g. budding, grafting, layering, marcoting, stem cutting, sulkers, bulbs crown, slips, leaves, and root cutting, cell division, binary fission in single celled animals e.g. Amoeba, bacteria, paramecium.

Sexual reproduction

This is the type of reproduction which involves joining (fusing) or two reproductive cells, male and female gametes.

The union /fission of a male female gametes is called fertilization.

The nuclei of the two cells unite and form a Zygote develops into a new individual or foetus.

In animals, the male reproductive cells (gametes) are called sperms and are produced by the reproductive organs called testes.

The female reproductive cells are called Ova and are produced by the ovaries.


These are animals that contain (have) both male and female reproductive organs (Testes and Ovaries) on themselves. E.g. earth worms and snails.

Types of fertilization

There are two types of fertilization

  1. External fertilization
  2. Internal fertilization

External fertilization

This is where the female lays eggs and the male pours sperms on them outside the mother’s body to fertilize them e.g. fish and amphibians.

Internal fertilization

This is when eggs are fertilized inside the mother’s body after mating.

Human sexual reproduction

Diagram showing the cross section of the female reproductive organs (system)

The female reproductive organs and their functions

The Ovary: there are two ovaries. One on the left and another on the right. Ovaries produce ova (ovum) the female reproductive cells.

Oviduct (fallopian tube): it is the tube down the uterus (womb) from the ovary. It is the passage for an ovum to the uterus. This is where fertilization takes place.

Uterus (womb): it is a bag like structure inside which the foetus or Zygote grows from.

Cervix: This is a ring of muscle which helps to close the lower end of the uterus to the vagina there by protecting it /foetus from external damage.

The structure of gametes

  1. Female gamete (an Ovum)
  2. Male gamete (sperm)

The structure of male reproductive organ

What is the reproductive system

Functions of parts of the male reproductive organ

Scrotum: it is a sac or bag that encloses and protects the testes.

Testes: these are glands that produce the male seminal fluids containing sperms; They lie outside the abdominal cavity to make them have lower temperature than the normal body temperature for maximum production of sperm; They start producing sperm cells during adolescence from age 11-16years

Epididymis: it is a long coiled tube which stores and then carries sperms.

Sperm duct: It is an extension of the epididymis and delivers the sperms to the urethra where they  pass and go out.

Prostrate gland: produce a fluid (seminal fluid) which helps to neutralize (make harmless/ the acid in urine in the urethra. It also kill germs which are in sperms.

Seminal vesicles: it stores excess sperms.

Erectile tissue (penis): it is a spongy tissue which when filled with blood it erects (stands) to ejaculate sperms.


This is when mature ova are released from the ovary.

An ovary releases an ovum every month i.e. the release of ova is done alternately.


This is the periodic release of blood from uterus as a result of rapture of the uterus walls when fertilization has taken place

This helps to wash and clean the uterus in preparation to receive a foetus.


The first menstruation called menarebe starts in girls between the age of 9-15 years.

The last menstruation period end at around 45 years and is called menopause

Normal menstruation takes 3-4 days.

It takes place after every 28 days if all conditions are normal.

It may be interrupted by conception, strong fever, or any abnormalities in the body.

Care during menstruation

  • To prevent infection and avoid germs, diseases, one must be clean.
  • Use sanitary materials such as tampax,  tampons, always, cotton.
  • Visit health workers incase abnormalities are noted.


  • Fertilization takes place in the oviduct /fallopian tube.
  • Immediately after fertilization, the zygote moves to the uterus.
  • The zygote attaches itself on to the placenta with the help of an umbilical cord, this process is called implantation.
  • The placenta supplies the embryo with food nutrients and oxygen at the same time it removes waste products.
  • The umbilical cord transports food to the foetus and waste products from the foetus to the placenta to be carried away by blood.
  • The period of pregnancy from conception to birth is called gestation period and lasts for 9 months in humans.
  • Development of the foetus takes place in the uterus.
  • The ammotic fluid act as shock absorber and protect the foetus.
  • The amnion/ amniotic membrane protects the body and had the fluids.

The stages of development are;

Fertilization  – Zygote  –  Foetus = baby

Diagram showing development of the foetus in uterus

What is the reproductive system

Sex determination

Sex of a child is determined by chromosomes found on the gametes/ sex cells, there are X and Y chromosomes XX chromosomes are for girls and XY for boys.  Sperms carry XX and XY chromosomes

Signs of pregnancy (good and Bad)

  • Morning sickness
  • Vomiting and nausea
  • Swollen legs
  • General body weakness
  • Swollen belly
  • Frequent urination
  • Faster breathing

Requirement s of an expectant mother (pregnant mother)

  • Good diet (balanced diet) for proper growth of the baby.
  • Should avoid taking drugs like tobacco and alcohol.
  • Should visit antenatal clinic for medical check up and advice.
  • Should rake vaccine against tetanus (texonus toxed)
  • Enough rest and sleep.
  • Wear maternity dresses to have comfort
  • Perform light physical exercises