Download The Neuron - MsHughesPsychology

Unit 3 Psychology
Area of Study 1: How does the nervous system enable
psychological functioning?
Key knowledge: Dot point 3
“The role of the neuron (dendrites, axon, myelin sheath and axon terminals) as the primary cell
involved in reception and transmission of information across the synapse (excluding details related
to signal transduction).”
The Neuron
A neuron is an individual nerve cell. The entire nervous system is comprised of neurons, organised
into complex chains and networks that form neural pathways.
A neuron is a cell that transmits and receives information in the form of neural impulses (neural
impulses are tiny pulses of electro-chemical energy)
A neuron has five main parts:
1. Dendrite: a branch-like extension of the neuron that receives information from other
neurons and transmits it to the soma.
2. Soma: the cell body that transfers information from the Dendrite to the Axon. The Soma
also contains the nucleus, which keeps the neuron functioning.
3. Axon: a long tube-like structure that transmits information away from the Soma and to the
next neuron in the neural pathway.
4. Axon Terminals: branches extend out from the axon and end in knob-like structures called
terminal buttons or synaptic vesicles. Each terminal button contains chemicals called
neurotransmitters that transmit the information from the Axon to the next neuron in the
neural pathway.
5. Myelin Sheath: a white, fatty substance that coats the Axon, insulating it and preventing the
information from leaving the neuron too early. It also speeds up neural transmission.
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Transmission between neurons – The Synapse
Synapse: the site where communication occurs between neurons.
Synaptic Gap (Cleft): microscopic gap between the axon terminals of one neuron and the dendrites
of another.
This gap is about 500 times thinner than a strand of hair.
When the neural message is passing along a neuron it is in an electrical form. Once the message
reaches the axon terminals it must be converted to a chemical (neurotransmitter) to cross the
synapse and be received by the next neuron.
The neuron sending the message is the Pre-synaptic neuron and the neuron receiving the message
is the Post-synaptic neuron.
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TYPES OF NEURONS
Sensory neurons
AKA: Afferent neurons.
Sensory neurons: specialised neurons that carry sensory information towards the CNS.
Sensory neurons receive and carry sensory information. They receive information the external and
internal environment, via our sense organs.
Motor neurons
AKA: Efferent neurons
Motor neurons: specialised neurons that carry motor commands from the CNS to the body.
Motor neurons enable movement in the body via muscles, organs and glands.
Interneurons
Interneurons: specialised neurons located in the spinal cord that transmit sensory information to
the brain and motor messages from the brain to the body.
Interneurons act as a link between the CNS and PNS.
*Neural message relay game
**Student Activity Manual – 1.6
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