Biology B3 Revision tool
- Created by: izzyblack
- Created on: 24-02-15 12:50
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- Biology revision
- Transpiration stream
- Water evaporates from palisade cells
- Water drawn from xylem cells in leaf to replace it
- Water molecules stick together - pulls more from leaf
- Sets of stream of replacement;
- Water in xylem replaced by water from xylem tube
- Water in xylem tube replaced from stem
- Water from stem replaced from roots
- Water in xylem tube replaced from stem
- Water in xylem replaced by water from xylem tube
- Sets of stream of replacement;
- Water molecules stick together - pulls more from leaf
- Water drawn from xylem cells in leaf to replace it
- Against concentration gradient
- Osmosis
- Water evaporates from palisade cells
- Controlling body temperature
- Temperature receptors in skin detect changes in external temp
- Send information to hypothalamus
- This area of brain has receptors for testing blood temp
- Triggers effectos to keep body temp at 27 deg Celsius.
- Effectors = sweat glands and muscles
- If we are too hot, the processing center sends nerve impulses to sweat glands to produce sweat
- Evaporation of sweat needs energy, cooling you
- If the air is humid, the sweat cannot evaporate as easily due to concentration difference of water being lower
- Hairs lie flat to let heat escape
- Evaporation of sweat needs energy, cooling you
- If too cold, vasoconstriction to bring blood into the body to keep it warm
- Hair sticks up to trap heat against skin
- Triggers effectos to keep body temp at 27 deg Celsius.
- This area of brain has receptors for testing blood temp
- Send information to hypothalamus
- Temperature receptors in skin detect changes in external temp
- Blood sugar control
- Too high;
- Insulin secreted by pancreas into blood
- Liver convers glucose into glycogen
- Glycogen is stored - blood sugar goes down
- Liver convers glucose into glycogen
- Insulin secreted by pancreas into blood
- Too low;
- Insulin not secreted into blood
- Too high;
- Transpiration stream
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