Reproduction

Reproduction

1. Fertilisation

   • Def: Fusing of male (sperm) and female (ovum) nucleus
   • Internal e.g. humans, birds, reptiles
   • External e.g. fish
   • Human fertilisation
     • Egg and sperm fuse
     • Cell division
     • Ball of cells
     • Embryo
     • Implantation (embryo implants into uterus lining)
     • Foetus (9-10 weeks) has limbs and looks like human

2. Puberty

   • Male
     • Testes produce sperm
     • muscles develop
     • Penis grows
     • Voice breaks
     • Growth spurt
     • Hair
       • Pubic
       • Facial
       • Underarm
     • Stronger smell
   • Female
     • Growth spurt
     • Stronger smell
     • Ovaries produce eggs
     • Breasts develop
     • Hips widen
     • Hair
       • Underarm
       • Pubic

3. Gametes

   • Sperm cell (male)
     • Tail, streamlined shape
     • Pointed head
     • Chemicals
     • Structures in cytoplasm for energy to swim
     • Nucleus (half genetic information)
     • Produced in testes (lower temperature)
     • Adapted for fertilisation
     • Released in sugary liquid (semen) , energy for respiration/swim
   • Egg cell/Ovum (female)
     • Food reserves in cytoplasm
     • Nucleus (half genetic information)
     • Jelly covering
     • Released from ovaries every 28 days in mature females

4. Contraception

   • Pill
   • Condom

5. Reproductive organs

   • Male
     • Testes (produce sperm)
     • Sperm duct (Carries sperm form testes to urethra)
     • Urethra
     • Penis (enters female)
   • Female
     • Ovaries produces eggs, released every 28 days)
     • Fallopean tubes/ oviducts (carries egg from ovary to uterus)
     • Uterus/ womb (baby develops)
     • Cervix (neck of uterus, sperm deposited here
     • Vagina (muscular tube where penis enters)

6. Menstrual Cycle

   • Monthly changes that occur in female reproductive system every 28 days
   • Why? To prepare uterus lining for fertilised eggs
   • Day 1-5. Lining shed i.e.period
   • Repair of uterus wall. Lining thickens
   • Day 14. Ovulation/egg release
   • Lining stays thick, waiting for fertilised egg
   • If no fertilised egg, cycle restarts
   • If fertilised egg, implants into uterus lining

7. Development of Foetus

   • umbilical cord
     • Carries food, oxygen, water from mother to baby
     • Carries CO2 and waste from foetus to mother
     • Acts as barrier to harmful substances but some pass through e.g. drugs, alcohol, tobacco and viruses
     • 2 bloods do not mix
   • Amnion
     • Amniotic fluid
       • Protects and supports foetus
     • Amniotic membrane
       • Breaks at birth
   • Placenta
     • Substances exchanged between mothers and foetal blood