Neuron Structure & Function (AQA GCSE Psychology): Flashcards

To carry signals from the CNS toward organs, muscles and glands (the PNS). They control physical movements such as the contraction and relaxation of muscles.

True.

Motor neurons have short dendrites and long axons — the reverse of sensory neurons, which have long dendrites and short axons.

They connect sensory neurons to motor neurons, and are located in the CNS, carrying signals across this part of the nervous system.

False.

Relay neurons have short axons and short dendrites.

A synapse is the junction at which two neurons meet.

The presynaptic membrane, the synaptic cleft, and the postsynaptic membrane.

It begins as an electrical impulse within the presynaptic neuron, then changes to a chemical messenger when sent across the synapse to the postsynaptic neuron.

When an electrical impulse arrives at the presynaptic knob, neurotransmitters are released from structures called vesicles at the presynaptic membrane.

Neurotransmitters are a chemical substance released from the presynaptic neuron after the action potential (electrical impulse) has occurred.

They diffuse across the synaptic cleft and temporarily bind with receptor sites on the postsynaptic membrane — a bit like a baseball glove catching a ball.

It stimulates the postsynaptic neuron to generate another electrical impulse, which then travels down the axon of the postsynaptic neuron.

False.

The neurotransmitter molecules are destroyed by enzymes or recycled, to prevent continued stimulation of the second neuron — which could otherwise cause repeated impulses to be sent.

It may be used again by the presynaptic neuron.

Excitatory neurotransmitters stimulate an action potential (electrical impulse) in the postsynaptic neuron. They increase the neuron’s positive charge, making it more likely to ‘fire’.

Adrenaline.

False.

Inhibitory neurotransmitters increase the neuron’s negative charge, making it less likely to ‘fire’ — they inhibit an action potential in the postsynaptic neuron.

An example of an inhibitory neurotransmitter is serotonin.

Thousands of signals from other neurons within a network of neurons — some of which will be excitatory and some inhibitory.

Summation occurs when there are enough excitatory signals compared to inhibitory signals — this causes the neuron to fire, creating an electrical impulse.

Once excitation reaches a certain point relative to inhibition, summation is what tips the neuron into firing.

1. An action potential starts the process. 2. It travels down the axon. 3. The electrical impulse turns into a chemical messenger (the neurotransmitter). 4. The neurotransmitter is released across the synaptic cleft. 5. Receptor sites on the postsynaptic neuron receive it. 6. Any remaining molecules are taken back into the presynaptic neuron (reuptake) or broken down by enzymes.

Brain plasticity refers to the brain’s ability to adapt to change — e.g. due to learning and experience.

That there is a connection between neurological and psychological processes.

Their brain forms and strengthens synaptic connections between neurons.

False.

Neural connections start weak but are strengthened with repeated practice.

A learner driver focuses on the controls of the car until they gain more experience, after which driving feels easy and automatic. Similarly, playing the piano is slow and awkward at first, but feels natural once sufficiently practised.

The brain’s plasticity comes from its ability to form new synaptic connections and strengthen existing ones, in the same way a muscle grows stronger the more it is used.

No — it is the result of weeks, months and years of practice, learning and experience.

An engram is a kind of trace left in the brain when an action or behaviour is repeated and practised, e.g. learning French at school.

The trace is not immediately erased or wiped out — it can be strengthened and bolstered by more practice, which is why experts in any discipline spend thousands of hours practising.

False.

The trace may fade (a case of ‘use it or lose it’) but not necessarily completely disappear — which explains why people can still ride a bike even if they haven’t done so for many years.

Cell assemblies are groups of neurons which Hebb proposed are created during learning — i.e. huge synaptic ‘firing’ — which in turn makes these neurons more efficient as they forge strong synaptic connections.

Because of neuronal growth — which explains why some professional footballers can score a goal from a corner kick, something that would be beyond most people.

Increased grey matter in their brains was linked to their years of practice navigating the complicated streets of London.

Draganski et al. found that participants who had learnt a juggling routine showed brain plasticity, compared to participants who had not learnt the skill.

It can be investigated using objective, scientific methods — e.g. the MRI scans used in Maguire et al. — which increases its validity.

Hebb argued that a stimulating environment helps cell assemblies grow and learn — which suggests that creating richer, more stimulating environments could encourage learning in an educational setting.

True.

This supports the idea that environment and learning are related, backing up Hebb’s application to education.

The theory is reductionist because it reduces learning to a neuronal level and ignores other explanations — such as learning as a cognitive process (e.g. similar to Piaget’s concept of accommodation) or as a social process (learning through observing others or being directly instructed).

It cannot explain why some people require less practice than others in mastering specific skills.