Nervous systems and reflex arc
Structure of a nerve cell
Structure of the whole nervous system
Reflex arcs
Nerve cells are referred to as neurons
Neurons are long, thin and have lots of branched connections on either end.
Synapse
This is the connection between nerve cells.
When an electrical current hits the end of a nerve cell it releases a set of chemical reactions to cross to the other side of the synapse.
Central nervous system or CNS
This is made up of the brain and the spinal cord
This is where sensory information is inputted and then orders sent out.
To get the inputs the CNS needs sensory neurons
These carry information from receptors to our nervous system.
Orders are sent out via motor neurons
These motor neurons take the signal out to effectors, which are normally muscles or glands
An example is moving your hand away from a hot pan
Reflexes are rapid and automatic
How it works:
The body receives a stimuli, which is detected by receptor cells within the skin
This will then stimulate a sensory neuron to the spinal cord
Inside the spinal cord the signal will be transferred to a relay neuron
The relay neuron will then send the signal on to a motor neuron
The signal is then sent out to an effector