Allows organisms to react to their
surroundings and co-ordinate their
behavior
Information gets passed
along neurons to the brain
The brain co-ordinates the response, which
is then carried out by an effector
The effector may be a muscle, which responds by
contracting, or a gland which responds by releasing
chemicals
Receptors..
Sensory Neurone
Relay Neurones
Spinal Chord or Brain
Motor Neurones
Effector
Types of Neurons
Motor Neurone
Impulse travels away from cell body
Sensory Neurone
Impulse travels towards cell body
Relay Neurone
Impulse travels
first towards, then
away from cell
body
Neurones are specially adapted cells that
can carry an electrical signal, e.g. a nerve
impulse
Neurones are elongated to
make connections between
parts of the body
Branched endings to
allow a single neurone to
act on many muscle
fibres
Cell body has many connections
to allow communication with
other neurones
Connections between Neurones
Neurones don't touch each other, there's a
small gap between them called a synapse
When an electrical impulse reaches the gap, a chemical
transmitter is released which activates receptors on neurone
B and causes an electrical impulse to be generated in
neurone B. The chemical transmitter is then destroyed.
Types of Receptor (receptors
detect stimuli)
Light
Sound
Change of position
Taste
Smell
Temperature
Pain
Touch
Pressure
Reflex Action
Sometimes conscious action is too slow to prevent harm to
the body, e.g. removing your hand from a hot plate
Reflex action speeds up the response time by missing out the brain entirely