Homeostasis and Response

• Temperature receptors are mainly found in the blood vessels and

  skin.
• Auxins change growth patterns to allow roots and shoots to move either towards or away from a stimulus (change in conditions).
• Tropisms are controlled by auxins. They are groups of responses that can be split into phototropisms and gravitropisms.
• Oestrogen pills prevent the release of Follicle-Stimulating Hormone(FSH) This prevents eggs from maturing in the ovaries. Progsterone in the pill prevents both Follicle-Stimulating Hormone(FSH) and Luteinizing Hormone(LH). This prevents eggs from being released from the ovaries. If eggs are not matured or released they cannot be fertilised. Contraceptive pills can also cause cervical mucus to thicken which prevents the entry of sperm into the uterus.
• Insulin causes glucose to be converted to glycogen. Thyroxine increases cellular respiration.These two processes will lower blood glucose levels.

  Glucagon causes glycogen to be converted back into glucose.Adrenaline stimulates the breakdown of glycogen into glucose.These two processes will increase blood glucose levels.
• The effects of dehydration on normal cells in our body


  Water would move out of cells. Water would leave by osmosis. Cells would become plasmolysed. The concentration of other solutes in the cell would increase. This would affect the chemical reactions that can occur in cells.
• 3 main ways our bodies warm up (with explanations)

  1. Vasoconstriction- the blood vessels get narrower to reduce the amount of blood flow to capillaries and therefore, reduce loss of heat energy
  2. Shivering- Respiration is required to make your muscles move to shiver. The respiration releases heat energy
  3. Hairs stand up + erector muscles contract- This traps insulating air
• 3 main ways our bodies cool down(with explanations)

  1. Vasodilation- the blood vessels get wider to increase blood flow to the capillaries and therefore increase the loss of heat energy
  2. Erector muscles + hairs relax/lower- This releases insulating air.
  3. Sweating- The sweat evaporating off our bodies removes heat energy from the skin