B1.2
- Created by: Meganallam
- Created on: 15-05-17 10:54
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- B1.2
- Nerves and hormones
- the nervous system enables humans to react to their surroundings and coordinate their behaviour
- receptors are cells that detect stimuli
- there are 5 sense organs and they detect different stimuli
- eyes = light
- ears = sound, position and keep balance
- tongue = chemicals in food and drink
- nose = chemicals in the air
- skin = touch, pain, pressure, temperture
- light receptor cells have a nucleus, cytoplasm and cell membrane
- information from receptors passes along neurones to nerves to the brain
- the brain coordinates the response
- reflex actions are automatic and rapid
- the nervous system enables humans to react to their surroundings and coordinate their behaviour
- control in the human body
- water content of the body is controlled
- water leaves the body via the lungs when we breath out and via the skin when we sweat. excess water is lost through the kidneys in the urine
- ion content is controlled
- ions are lost via the skin when we sweat and excess ions are lost via the kidneys in the urine
- temperature is controlled
- to maintain the temperature at which enzymes work best
- blood sugar levels are controlled
- to provide the cells with a constant supply of energy.
- water content of the body is controlled
- Control in Plants
- plants are sensitive to light moisture and gravity.
- their shoots grow towards light and against gravity.
- their roots grow towards moisture and with gravity
- plats to produce auxin which controls phototropism and gravitropism
- the response of plant roots and shoots to light, gravity and moisture air the results of unequal distribution of hormones causing unique growth rates
- plant growth hormones are used in agriculture and horticulture as weed killers and as rooting hormones.
- plants are sensitive to light moisture and gravity.
- Nerves and hormones
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