5 different sense organs-ears,eyes,nose,tonge&skin
all contain diff receptors-are groups of cells which are sensitive to a
stimulus. they change stimulus energy into electrical impulses.
a stimulus could be light,sound,touch,pressure,pain,chemical or a change in position or temperature.
5 sense organs&receptors
eyes-light receptors-sensitive to light&cells have
nucleus,cytoplasm&cell membrane(like most animal cells)
ears-sound receptors-sensitive to sound-also
balance receptors to changes in position
nose-smell receptors-sensitive to chemical stimuli
tounge-taste receptors-sensitive to
bitter,sour,salt&sweet&savoury things-chemical stimulus
skin-sensitive to touch,pressure,pain and temp change
sensory neurones-nerve cells carry signals as electrical impulses
from the recpeptors in the sense organs to central nervous system
Relay neurone-nerve cells carry signals from sensory Neurones to motor neurones
motor neurones-nerve cells carry signals from central nervous system to effector muscles or glands
Effectors
respond in diff ways. muscles contract in response to a nervous impulse,
whereas glands secrete hormones
Central Nervous System(CNS)
coordinates a response
all info from sense organs is sent&where reflexes &actions are coordinated.
consists of brain&spinal chord only.
neurones(nerve cells) transmit info(as electrical
impulses)very quickly to&from CNS instructions from CNS
are sent to the effectors(muscles&glands) which respond
accordinly.