cognito 2

• Puberty


  The period during which adolescents start to develop secondary sexual characteristics
• Secondary sexual characteristics


  • Facial hair in men
  • Breasts in women
• Reproductive hormones


  Hormones that trigger puberty, including testosterone in men and estrogen in women
• Testosterone is produced in the testes and stimulates sperm production
• Estrogen is produced by the ovaries
• Menstrual cycle


  1. Menstruation

  2. Uterus lining building up

  3. Ovulation

  4. Maintaining uterus lining
• Menstruation


  Period of bleeding due to the breakdown of the uterus lining
• Uterus lining building up

  Thick spongy layer with blood vessels to prepare for fertilized egg
• Ovulation


  Release of egg from ovary
• Maintaining uterus lining


  Progesterone maintains the lining of the uterus
• If no fertilized egg implants, the uterus lining breaks down and the cycle repeats
• If a fertilized egg implants, the menstrual cycle stops as the woman is pregnant
• Estrogen


  Produced in the ovaries, stimulates the uterus lining to grow
• Progesterone


  Produced in the ovaries, maintains the lining of the uterus
• Luteinizing hormone (LH)


  Produced in the pituitary gland, stimulates the release of the egg (ovulation)
• Follicle stimulating hormone (FSH)


  Produced in the pituitary gland, stimulates the maturation of an egg in the ovaries
• FSH stimulates the ovaries to produce estrogen


  As estrogen levels increase, they start to inhibit FSH (negative feedback)
• High estrogen levels


  Stimulate the release of LH, causing ovulation
• Progesterone


  Inhibits both LH and FSH
• Contraception


  Any artificial method that people use to prevent pregnancy
• How pregnancy starts


  1. FSH stimulates an egg in one of the ovaries to develop

  2. LH triggers the release of the egg (ovulation)

  3. Egg passes along the fallopian tube

  4. Egg could combine with a sperm cell to form a fertilized egg

  5. Fertilized egg continues along the fallopian tube to the uterus and implants into the wall
• Cervix


  The entrance to the uterus
• Categories of contraception methods

  • Hormonal
  • Non-hormonal
• Hormonal contraception


  • Relies on releasing estrogen, progesterone, or a combination
  • Estrogen inhibits FSH production, preventing egg development
  • Progesterone stimulates thick mucus in the cervix, preventing sperm from reaching the egg
• Copper IUD


  Doesn't involve hormones, prevents sperm from surviving in the uterus
• Non-hormonal contraception


  • Prevents sperm from meeting the egg
• Abstinence is the only 100% effective way to avoid pregnancy
• Contraceptives


  Used to reduce fertility and prevent pregnancy
• Infertile


  Unable to have children naturally
• Increasing fertility using hormones

  1. Give FSH to stimulate egg maturation

  2. Give LH to stimulate ovulation
• FSH


  Follicle stimulating hormone, stimulates ovaries to mature eggs
• LH


  Luteinizing hormone, stimulates ovulation
• IVF (In Vitro Fertilization)


  1. Stimulate egg maturation with FSH/LH

  2. Collect eggs

  3. Fertilize eggs with sperm

  4. Incubate fertilized eggs (embryos)

  5. Transfer embryo to uterus
• In vitro


  Outside the body, e.g. in a laboratory
• In vivo


  Inside the body
• ICSI


  Intracytoplasmic sperm injection, sperm injected directly into egg
• Genetic testing of embryos is possible with IVF, raising concerns about "designer babies"
• Genetic testing and selection of embryos is currently illegal in the UK and most other countries
• Auxins


  Plant hormones that control growth at the ends of shoots and roots
• How auxins work


  1. Produced in tips

  2. Dissolve in cell solution

  3. Diffuse backwards along shoot or root