Human reproduction

• Reproduction


  The process of producing new organisms
• Sexual reproduction


  Requires two parents to produce an offspring
• Asexual reproduction


  Requires only one parent to produce offspring
• Puberty


  The time when the human body becomes sexually mature
• Hormone


  A chemical substance produced by the body to control the activity of cells/organs
• Changes during puberty in females (controlled by oestrogen)


  • Voice deepens
  • Hips widen
  • Breasts develop
  • Ovaries begin releasing egg cells - menstruation begins
• Changes during puberty in males (controlled by testosterone)

  • Voice breaks
  • Facial hair grows
  • Body becomes more muscular
  • Testes begin to produce sperm
• Changes during puberty in both

  • Sexual organs grow/develop
  • Pubic/underarm hair grows
  • Height increases
  • Acne
• Male reproductive system


  • Bladder holds urine
  • Seminal vesicle produces prostate fluid
  • Prostate gland produces prostate fluid
  • Urethra moves semen from vas deferens and urine from bladder out of the body
  • Penis passes semen into the vagina
  • Vas deferens moves sperm from testes to penis and collects fluids from glands
  • Testes produce sperm and testosterone
  • Scrotum holds testes
• Female reproductive system


  • Uterus holds foetus and expands during pregnancy
  • Fallopian tube collects eggs from ovary and is the site for fertilisation
  • Ovary produces/stores eggs and produces oestrogen
  • Cervix connects womb to vagina and widens during childbirth
  • Vagina receives penis during sexual intercourse and is the birth canal
• Sexual intercourse


  The placement of the penis inside the vagina
• Ejaculation


  Semen is ejected from the body
• Fertilisation


  The fusion of male and female gametes to form a zygote
• Zygote


  The first cell of the new organism, resulting from the fusion of the egg and sperm at fertilisation
• Fertilisation, implantation, conception


  1. During ovulation, an egg is released from the ovary

  2. The egg is fertilised in the fallopian tube by the sperm to become a zygote

  3. Zygote grows to become a clump of many cells developing into an embryo

  4. Embryo travels to uterus, where it embeds itself in the thickened lining to develop further (implantation)

  5. When this happens, parents have conceived and the female is pregnant
• Implantation


  When the embryo embeds itself into the thickened lining of the uterus
• Conception


  When the embryo successfully implants into the wall of the uterus
• Menstrual cycle


  1. Day 1-5: An egg is not implanted, the lining of the uterus breaks down

  2. Day 5-13: The lining of the womb starts to build back up as an egg is developing in the ovary

  3. Day 14: Ovulation, egg released from one of the ovaries

  4. Day 15-18: Lining continues to thicken, the uterus is ready to nourish an embryo if implantation occurs
• Menstruation/Periods


  The stage where the lining of the uterus breaks down and is released through the vagina
• Ovulation


  The release of an egg from the ovaries
• Fertile period


  The time when pregnancy is most likely to occur, days 11-17
• Pregnancy and birth


  • Placenta develops at 12 weeks, brings nutrients to the foetus and removes waste
  • Umbilical cord connects the foetus to the placenta, cut at birth
  • Amniotic sac protects the foetus inside the uterus
  • Amniotic fluid surrounds the foetus inside the amniotic sac
• Just before birth


  1. Muscles in the uterus contract and baby moves towards the cervix

  2. The cervix dilates

  3. The amniotic sac breaks, releasing amniotic fluid
• Birth


  1. Contractions get stronger, the baby is pushed past the cervix and out of the vagina (head first)

  2. Umbilical cord is clamped and cut

  3. The last contraction pushes the placenta out of the birth canal
• Contraception


  A means to prevent fertilisation/implantation by natural or artificial methods to avoid pregnancy
• Infertility


  The inability to produce an offspring
• IVF


  A method of fertilisation that happens without sexual intercourse
• STI/STD


  Sexually transmitted infections/diseases are infections or diseases spread through sexual intercourse