Slides in this set
What is the nervous system?
The Nervous System allows the body to
respond to changes in the environment
This change in environment is detected
by receptors in the five sense organs.
Ears-Sound and orientation receptors
Nose and Tongue-Chemical receptors
Skin-Temperature and pressure
This process involves neurones and it is
usually coordinated by the brain unless
it is a reflex action.…read more
Structure of a neurone
Dendron Cell Body
· Neurones transmit information around the body
· Impulses enter a neurone through the dendrite ending
· Impulses travel through a dendron to the cell body
· The impulse is sent from the cell body through the axon and reaches the synapse
· The myelin sheath is a coating around the axon. It insulates the message so that
the electrical impulse is not lost which makes it travel faster.…read more
The reflex arc
A reflex action prevents injury. It is an automatic response that is not
controlled by the brain.
·Receptor cells detect a stimulus - change in the environment.
·The sensory neurone sends electrical impulses to the relay neurone.
·The relay neurone sends these impulses to the motor neurone which
sends a signal to the effector.
·The effector produces a response. This could be a muscle or a gland.
Pain receptor Sensory neurone Connecting relay neurone
in finger carries nerve impulse to carries impulse from the
spinal cord sensory to motor neurone.
carries impulses Spinal
from spinal cord cord
Biceps muscle bends arm…read more
· Where two neurones meet, the gap is
called the synapse.
· The signal is transmitted across this gap
by chemicals released by the neurone,
· When the electrical impulse reaches
the synapse it triggers the nerve-ending
of a neuron to release the
· These chemicals diffuse across the
synapse and bind with receptor
molecules on the membrane of the
· This stimulates the second neuron to
transmit the electrical impulse.…read more