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Nerves CA
Receptors are energy transducers ­ convert energy from one form to another
Each detects a different energy form

receptor Energy changes detected
Rod & cone cells in retina Light intensity and range of wavelength
Sound receptors in inner ear Vibrations in air
Olfactory cells lining inner surface of…

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Nerves CA

Motor neurone

Relay neurone


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Nerves CA

Similarities Differences
Sensory and motor Motor neurones have their
neurones are long to cell body within the CNS
transmit AP over long
Sensory & motor neurones Sensory neurones have
are surrounded by a fatty their cell body just outside
myelin sheath (a series of the CNS

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Nerves CA
Have a cell body containing Sensory neurones have a
the nucleus, many short axon to transmit AP
mitochondria and to the CNS
dendrites to connect with Sensory neurones have a
other neurones long dendron to transmit
AP from receptor to cell
feature mylinated Non-mylinated
Speed of…

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Nerves CA
Where found In peripheral nervous system IN CNS and in nerves
carrying impulses to/from CNS controlling organs with no
conscious control

Resting potential is -65mv.
Outer surface positively charged, inner surface negatively charged = polarised
Generated by sodium-potassium pump ­ channel protein in membrane.
Three Na+ out (active…

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Nerves CA
the neurone from one node to
the next.

- A synapse is a junction
between 2 or more
- Between 2 neurones is a
small gap, the synaptic
cleft, about 20nm wide
- An action potential cannot
bridge this gap. Instead,
the pre synaptic action
potential causes…

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Nerves CA
- This then generates a new action potential in the post synaptic neurone

In a cholinergic synapse the neurotransmitter = Acetylcholine
A synapses role is to allow signals from different parts of the nervous system to create the same

AP arrives at synaptic knob / pre-synaptic membrane…

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Nerves CA
If sufficient depolarisation to reach the threshold potential, a new AP is
generated in the post synaptic neurone



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