B5

• In the menstrual cycle, the release of an ovum is called ovulation.
• The monthly loss of blood from the lining of the uterus is referred to as menstruation or a period.
• Ovulation (the release of an egg) occurs in the ovary.
• After ovulation and successful fertilisation, a fertilised egg (zygote) sinks into the thickened lining of the uterus.
• FSH stands for Follicle Stimulating Hormone
• LH stands for Luteinizing Hormone.
• When FSH reaches the ovary, it causes an ovum to mature.
• When LH reaches the ovary, it causes a mature ovum to be released from the ovary.
• Both FSH and LH are secreted by the pituitary gland (situated in the brain)
• These four hormones coordinate the menstrual cycle:

  • Luteinizing Hormone (LH)
  • Follicle Stimulating Hormone (FSH)
  • Oestrogen
  • Progesterone
• A woman who is able to get pregnant is said to be fertile.
• Contraceptives are meant to prevent pregnancy and include condoms, the birth control pill and IUDs.
• Oral contraceptives are given in the form of pills.
• The first birth control pills had very high levels of oestrogen, but levels were reduced due to side effects.
• IVF stands for In Vitro Fertilisation.
• There is no guarantee that a women who undergoes IVF treatment will become pregnant.
• Fertility treatment does not decrease the chances of having twins/triplets.
• Ovulation occurs approximately once every 28 days.
• Luteinising hormone (LH) stimulates the cells in the ovary to undergo ovulation.
• Oestrogen is made in the ovaries.
• Oestrogen stops or slows down the production of Follicle Stimulating Hormone (FSH).
• If an egg released at ovulation is not fertilised, the lining of the uterus does not become thicker. Instead, the uterus lining is shed as a period.
• Ovulation occurs on day 14 of the menstrual cycle.
• When an ovum implants, pregnancy occurs.
• When an egg is released from an ovary, an empty follicle remains. This secretes the hormone progesterone.
• Progesterone skin patches inhibit the maturation and release of eggs from the ovary for as long as the patches are worn.
• Fertility treatments can result in multiple births, which is dangerous for the mother and children as it puts a strain on the body.
• The main stimuli that plants respond to are:

  • Light
  • Water
  • Gravity
• Shoots grow towards light while roots grow towards water in the soil.
• A tropism is a growth movement in plants.
• The hormone auxin controls both phototropism and geotropism in plants.
• New plants can be grown by taking cuttings from existing plants and growing new roots using hormone rooting powder.
• Rooting powder stimulates stem cuttings to develop roots.
• Hormones can be sprayed onto fruit to make sure they don't rot before they're sold.
• Shoots grow in the opposite direction to gravity
• The growth movement of a plant in response to light is called phototropism.
• A growth movement of a plant in response to gravity is called geotropism.
• The dark side of the shoot has a higher concentration of auxin than the light side.
• Auxin increases the growth of a shoot.
• A plant placed in a dark room will grow straight up (away from gravity) as there is no light source to grow towards.