Ch9: Reproduction

• Reproduction - the process where offspring are made from their parents, one of the seven characteristics of life.

  Gametes - sex cells, the egg and sperm

  Fertilisation - when the nucleus of the sperm fuses with the nucleus of the egg, forming a zygote.

  Zygote - fertilised egg.
• Testes - produce sperm and testosterone

  Scrotum - holds testes and keeps them below 37c so the sperm survives

  Sperm duct - carries sperm from testes to urethra

  Seminal vesicle - produces seminal fluid for sperm to swim in

  Urethra - sperm ducts pass semen into the urethra

  Foreskin - protects penis
• Primary male sexual characteristics:

  • Sperm production

  Secondary male sexual characteristics:

  • Growth spurt
  • Broader shoulders
  • Deeper voice
  • Sex drive
  • Growth of body and facial hair

  Testosterone - produced in testes, controls secondary male sexual characteristics
• Vagina - holds the penis during intercourse, known as the birth canal

  Cervix - Narrow passage between vagina and uterus, widens during birth

  Uterus/womb - where the baby grows and develops

  Fallopian tube/oviduct - collects eggs from ovary, the place where fertilisation occurs

  Ovary - produces eggs and oestrogen
• Primary female sexual characteristics:

  • Production of eggs

  Secondary female sexual characteristics:

  • Development of sex organs (ovaries) and breasts
  • Widening of hips
  • Growth of pubic hair

  Oestrogen - produced in the ovaries, the hormone that controls secondary female sexual characteristics
• Menstrual cycle - the 28 day series of changes a woman faces to prepare for the possibility of pregnancy.

  Day 1-5; Menstruation: Eggs begin to mature

  Day 6-14; Blood and tissue build up in uterus: Egg continues to mature

  Day 14; Ovulation: Egg is released from the ovary

  Day 15-28; Blood and tissue remain in uterus: hormones are released to maintain uterus lining

  • Cycle finishes on day 28 and restarts on day 1
• Amniotic fluid - contained within a skin-like membrane (the amnion) which protects the baby

  Placenta - a mass of tissue that passes nutrients and oxygen from the mother's blood to the baby, and passes waste (ex, CO2) from the baby to the mother's blood

  Umbilical cord - connects the baby to the placenta

  • Whatever the mother consumes while pregnant, the baby consumes it as well
• During birth;

  • The vagina gets wider
  • The amnion bursts and the amniotic fluid flows out of the vagina - this is known as the water breaking
  • The muscles of the uterus contract and dilate by 10cm until the baby is pushed out, to the outside world
  • After the baby exits, the placenta is removed from the uterus
• Contraception methods:

  Natural; Abstinence - simply avoiding sexual intercourse will prevent pregnancy, or planning around the menstrual cycle

  Artificial, mechanical - condom - a sheath placed over the penis that collects the semen after ejaculation, preventing it entering the vagina

  Artificial, chemical - the pill - a pill containing a hormone that prevents ovulation