groups of cells which are sensitive to a stimulus. they change stimulus energy into electrical impulses
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a stimulus can be...
light, sound, touch, pressure, pain, chemical or a change in position or temperature
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which sense organs contain which receptors?
eyes-light, ears-sound & balance, nose-smell (sensitive to chemical stimuli), tongue-taste(chemical stimuli), skin-touch, pressure & temperature change
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what does the central nervous system consist of?
the brain and the spinal cord
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what is the cns?
its where all the information from the sense organ is sent & where reflexes and actions are coordinated
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what transmits the information to and from the cns & how?
neurones and as electrical impulses
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hows does the cns respond?
they instruct the effectors who respond accordingly
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what are the 3 neurones called?
sensory, relay, motor
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what do each neurone do?
sensory-carry signals (electrical impulses) from receptors to cns, relay-carry signals from sensory neurones to motor neurones, motor-carry signals from the cns to the effector
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what are effectors and how do they respond?
muscle and glands. muscles contract. glands secrete hormones.
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what connects 2 neurones?
synapses
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how do the nerve signals transfer across the gap?
by chemicals (which diffuse) and the set off a new electrical signal in the next neurone
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what are reflexes and what do they do?
they are automatic responses to certain stimuli-they can reduce the chance of being injured
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what is the passage of information in a reflex called?
the reflex arc
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does the reflex arc go through the cns?
yes
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in a reflex arc, what happenes from stimulus to response and in what order?
what is the process of a reflex arc in more detail?
(1) bee sting (2) stimulation of the pain receptor (3) impulses travel along the sensory neurone (4) impulses are passed along relay neurone via a synapse (5) impulses travel along a motor neurone via a synapse (6) impulses reach muscle it contracts
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