Reproductive system

• testes

  Responsible for making sperm and are involved in producing a hormone called testosterone.
• scrotum

  Protecting the testes, keeps temperature slightly lower than the body temperature.
• vas deferens


  Transports mature sperm in preparation for ejaculation
• prostate gland

  Produces seminal fluid. Alkaline fluid and contains many chemicals including enzymes. It plays an important role in keeping sperm cells alive once they enter the female reproductive system.
• seminal vesicle


  Also contributes some of the liquid that makes up semen. The fluid produced by the seminal vesical contains proteins, enzymes, sugar, vitamin C and other substances. The sugar provides a source of energy for sperm cells.
• urethra

  The tube inside the penis through which  semen leaves male body
• penis

  The penis swells during arousal. Semen containing sperm cells is ejaculated.
• Testes

  Produce sperm cells
• Scrotum


  • Keeps testes a few degrees cooler than body temperature
  • This is essential for sperm production (spermatogenesis)
• Sperm production

  1. Sperm cells travel away from the testes via the vas deferens

  2. Prostate gland and seminal vesicle produce substances that assist the sperm cells on their journey through the female reproductive system

  3. Sperm cells reach the urethra in the penis and are bathing in a fluid called semen
• Sperm cell

  • Has three sections: head, middle region, and tail
  • Head contains the nucleus with the chromosomes and the acrosome which enables the sperm to penetrate the egg
  • Middle section contains mitochondria which produce energy
  • Tail is a long and slender flagellum that serves to move the sperm
• An adult male produces sperm continuously, several hundred million each day of his life
• Sperm that are not ejaculated from the body are reabsorbed in a continual process of renewal
• ovary


  Produces ova. One egg is produced about once a month from one of the ovaries.
• fallopian tube/ oviduct


  Tubes through which ova must travel to reach the uterus. Fertilisation occurs in the fallopian tubes.
• Uterus

  Where the baby grows and develops.
• cervix

  The passageway between the vagina and the uterus. During childbirth the cervix needs to dilate(open up) to allow the baby to come out of the uterus.
• vagina


  Semen enters the female's reproductive system via the vagina. When babies are born they are pushed out of the uterus and must pass through the vagina to enter the world.
• Ova (eggs)


  Produced by females in their ovaries
• Ovulation

  One mature ovum from one of the ovaries is produced each month
• Most eggs will not be fertilised
• Menstruation

  Unfertilised eggs are expelled from the body through the uterus
• Ejaculation

  Sperm is released from the penis during sexual intercourse
• Fertilisation

  Sperm travel through the cervix, into the uterus and eventually reach the fallopian tube where they may fertilise an ovum
• The ovum must be fertilised within about 48 hours or it will die
• Only one sperm cell will fertilize one egg
• Zygote


  The fertilised egg
• Zygote development

  The zygote continues to move along the fallopian tube towards the uterus, dividing into 2 cells, then 4, then 8 and so on
• Implantation

  By day 4 the zygote, now a ball of cells called a foetus, enters the uterus and implants in the uterine lining
• Foetal development

  The foetus continues to divide and multiply itself in the uterine lining, developing into a baby over the next 9 months
• Umbilical cord

  A structure that allows the exchange of substances between the mother's and baby's blood
• Sex chromosomes

  Egg cells have a uniform X chromosome, sperm cells have either an X or Y chromosome
• If both cells have an X chromosome, the offspring will be female
• If the cells have different sex chromosomes, the offspring will be male