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6.5 Nerves
Homework
6.5.1 State that the nervous system consists of the central
nervous system (CNS) and peripheral nerves, and is
composed of cells called neurons that can carry rapid
electrical impulses.
6.5.2 Draw and label the structure of a motor neuron, include;
dendrites, cell body with nucleus, axon, myelin sheath, nodes of Ranvier, motor end plates.
6.5.3 State that nerve impulses are conducted from receptors to
the CNS by sensory neurons, within the CNS by relay
neurons, and from the CNS to effectors by motor neurons.
Outcome
To understand how and why animals respond to
their environment
1.
Central nervous system
2.
Peripheral nervous system
3.
Stimulus
4.
Receptor
5.
Central nervous system
6.
Motor neuron
7.
Effector
8.
Response
What is it made of?
Central Nervous System
(CNS)
Neurons in the brain and spinal chord.
Peripheral Nervous System
(PNS)
Neurons connecting the brain and
spinal chord to the body. (Motor &
sensory neurones)
TASK:
Label the CNS and PNS:
http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/human/thenervoussyste
mact.shtml -
Key Facts
When neurons are stimulated
they send rapid electric impulses.
 Super fast messages.
 Gaps between neurones: synapses
 Impulses travel from one neuron to
another across synapses .

There are hundreds of types!
Remember: axons take impulses away from cell bodies.
LO1: Describe the structure of neurons
LO2: Relate the structure of neurons to their function
Task
Annotate the diagram: link STRUCTURE to FUNCTION.
Long axon (cytoplasm extension) to send electrical impulses from central
nervous system to motor neuron.
2. Myelin sheath insulates the axon, speeding-up transmission of electrical
impulses.
3. Arrow to show the direction of the nerve impulse.
4. Node of ranvier, a periodic gap in the myelin sheath
5. Cell body/nucleus (axon hillock) which integrates signals
6. Motor end plate which transmit impulses across synapses to other neurons
1.
EXT Label one place at either end of the neuron where you would
expect to find a synapse (gap between two neurons which
communicate)
Check and add to your
answers:
Node of ranvier
Myelin Sheath
Motor end
plates
6. Neuron endings: All neuron endings
will have synapses to connect to other
neurons and send messages
Direction of impulse
6. Connections to cell
body will have incoming
synapses.
Long
Axon
Cell body
Nucleus (axon
hillock)
Smell
Touch
Pressure and
temperature
Sight
Light
Tongue Taste
Hearing
Sound and
Balance
Collect info and send it to sensory neurons
Receptors can be part of organs, like the eye.
Stimulus:
Loud Sound
Neurons : SRM
Receptor:
Sensory neuron in ear
Relay neuron:
Brain/Spinal chord (CNS)
Effector:
Motor Neuron/Gland
Response:
Jump
https://www.youtube.com/watch?v=OdOOIxcUjAs
Label the diagram to show how he responds and survives, including PNS, CNS
and names of each parts of the circuit
Car comes towards
Relay
man in daylight
in
PNS
CNS
PNS
1.
What two things make up the central nervous system?
Brain and spinal chord
2.
What is a receptor? Explain and give an example.
Something that receives information. Receptors in the ear receive sound.
3.
What is an effector? Explain and give an example.
Something that causes a response. Receives message from motor neurone and causes muscle/gland
response.
4.
Why do animals need to respond to stimulus?
To survive / Avoid horrible painful deaths.
Ext: Give an example of an animal responding to a stimulus: give
examples of stimulus, receptor, CNS, effector and response.
(Draw a flow map if its easier)
HeatTemperature receptor in skin relay neurone in CNS Effector = Muscle
Response = Movement away from heat
Stimulus – bright light in eyes
Stimulus  Receptor  Sensory Neuron  Relay Neuron
Motor Neuron  Effector  Response
Response – raise hand to shield eyes