Reproduction

• Stages in the life cycle

  1. The foetus grows in the womb

  2. A baby is born, learns to hold head up, sit, crawl, say words

  3. Toddler learns to walk, run, say 100 words

  4. Childhood starts at 3, learn new skills like reading

  5. Early adolescence 10-14, reproductive system begins to develop

  6. Late adolescence 15-18, body almost fully developed

  7. Adulthood 19-39, body fully developed

  8. Middle age 40-60, ageing begins to show

  9. Old age, adults get older, shorter, weaker
• Sexual characteristics


  Physical differences between men and women
• Types of sexual characteristics

  • Primary sexual: Differences in reproductive organs
  • Secondary sexual: Other physical differences like wider hips in women, more body hair in men
• Puberty


  Time in life when a boy or girl becomes sexually mature, usually 10-16 for girls, 12-16 for boys
• Puberty in girls


  1. Breasts begin to develop

  2. Pubic and armpit hair grows

  3. Girls grow taller and fill out

  4. Skin and scalp produce more oil, can cause acne

  5. Menstruation typically starts 10-15 years old
• Puberty in boys


  1. Pubic hair grows, also on face and under arms

  2. Voice deepens

  3. Boys become taller and heavier

  4. Skin becomes coarse, can develop acne

  5. Testicles enlarge, scrotum becomes larger and coarser

  6. Penis grows, boys become fertile
• Sperm cell


  Has oval shape and tail to swim up fallopian tubes and fertilise ovum
• Male reproductive system


  1. Testicles produce and store sperm

  2. Sperm travels through vasa deferentia to seminal vesicles

  3. Prostate produces liquid that forms part of semen

  4. Semen carries sperm and gives it nutrients

  5. Sperm travels through urethra to outside of body
• Female reproductive organs


  Located in lower abdomen, mostly internal
• Female reproductive organs


  • Ovaries: Produce ova
  • Fallopian tubes: Connect ovaries to uterus
  • Uterus: Muscular organ where fertilised cell develops into baby
  • Vagina: Muscular tube connecting uterus to outside of body
  • Vulva: Covers opening to vagina
• Menstruation


  1. Ovaries release ova every 28 days (ovulation)

  2. Uterus lining thickens in preparation for fertilisation

  3. If no fertilisation, ovum dries up and leaves body, along with uterus lining (menstruation)

  4. Menstruation typically lasts 3-5 days

  5. Menopause occurs when woman has no more eggs left, usually around age 50
• Human reproduction


  Involves female ovum and male sperm, each carrying different genetic information
• Pregnancy


  1. Fertilisation: Sperm fertilises ovum in fallopian tube

  2. Embryo development: Zygote travels to uterus, cells divide and multiply

  3. Foetus development: Embryo fixes to uterus lining, organs form, connected to placenta by umbilical cord

  4. Birth: Foetus pushes against cervix, which opens, baby passes through birth canal, umbilical cord cut