Animal Coordination, Control and Homeostasis GCSE EDEXCEL

• Osmoregulation


  Regulating water content
• Thermoregulation


  Regulating body temperature
• Blood glucose regulation


  Maintaining the right amount of glucose in the blood
• Homeostasis


  • Maintaining a constant internal environment
  • Responding to internal and external changes
  • Balancing inputs and outputs
• Examples of homeostasis


  • Osmoregulation
  • Thermoregulation
  • Blood glucose regulation
• Negative feedback system


  A response is triggered that counteracts a change in conditions away from the normal level
• Insulin and glucagon control of blood glucose concentration


  1. Eating carbohydrates puts glucose into blood

  2. Normal metabolism removes glucose from blood

  3. Vigorous exercise removes more glucose from blood

  4. Excess glucose stored as glycogen and fat

  5. Pancreas monitors and controls blood glucose using insulin and glucagon
• Blood glucose concentration too high so


  Insulin is added to remove glucose from blood
• Blood glucose concentration too low so


  Glucagon is added to release glucose into blood
• Describe Metabolism

  Process that removes glucose from the blood
• Vigorous exercise


  Removes much more glucose from the blood
• Excess glucose


  Can be stored as glycogen in the liver and muscles
• When glycogen stores are full


  Excess glucose is stored as lipid (fat) in the tissues
• Blood glucose


  Monitored and controlled by the pancreas using the hormones insulin and glucagon
• Controlling high blood glucose


  1. Insulin is added

  2. Insulin makes liver turn glucose into glycogen

  3. Blood glucose reduced
• Controlling low blood glucose


  1. Glucagon is added

  2. Glucagon makes liver release glucose into blood

  3. Blood glucose increased
• Infertility


  Inability to reproduce naturally
• Clomifene therapy


  Drug that causes more FSH and LH to be released, stimulating egg maturation and ovulation
• IVF


  Eggs collected from woman's ovaries, fertilised in lab, then embryos transferred to woman's uterus
• Assisted Reproductive Technology (ART)


  Fertility treatment involving handling and fertilising eggs outside the body
• Hormonal contraceptives


  Oestrogen prevents egg release, progesterone thickens cervical mucus to block sperm
• Hormonal contraceptive methods


  • Combined pill
  • Contraceptive patch
  • Mini-pill
  • Contraceptive injection
• Barrier contraceptive methods


  • Condoms (male and female)
  • Diaphragms
• Diaphragms


  Must be used with a spermicide to kill sperm
• Hormonal contraceptives


  • More effective at preventing pregnancy than barrier methods
  • Couple don't have to think about contraception each time
• Hormonal contraceptives


  • Can have unpleasant side-effects
  • Don't protect against sexually transmitted infections
• Menstrual cycle


  Monthly sequence of events where the female body releases an egg and prepares the uterus
• Stages of the menstrual cycle

  1. Menstruation

  2. Uterine lining repair

  3. Egg development and release

  4. Uterine lining maintenance
• FSH

  Follicle-stimulating hormone released by pituitary gland, causes follicle maturation and oestrogen production
• Oestrogen

  Hormone released by ovaries, causes uterine lining to thicken and grow
• LH


  Luteinising hormone released by pituitary gland, stimulates ovulation and corpus luteum formation
• Progesterone

  Hormone released by corpus luteum, maintains uterine lining, inhibits FSH and LH release
• If a fertilised egg implants, progesterone level stays high to maintain uterine lining during pregnancy
• Adrenaline

  Hormone released by adrenal glands, prepares body for 'fight or flight' response
• Thyroxine


  Hormone released by thyroid gland, regulates metabolic rate
• Negative feedback control of thyroxine

  1. Low thyroxine detected

  2. Hypothalamus releases TRH

  3. Pituitary releases TSH

  4. Thyroid releases thyroxine

  5. High thyroxine detected

  6. Hypothalamus and pituitary release inhibited
• Hormones have slower, more general effects compared to fast, precise neuronal responses