Neurons Flashcards
What is a neuron
Individual nerve cells that make up the nervous system
+ Information is communicated around the nervous system via electrical and chemical signals
What is the sensory neurone
Sensory neurons carry information from the sense organs to the central nervous system (CNS).
What is a motor neuron
Motor neurons stimulate muscles for movement.
Motor neurons send signals from the brain to the muscles.
What is a Relay Neurons
Relay neurons have a cell body surrounded entirely by dendrites.
Relay neurons pass messages to other neurons within the central nervous system (CNS) and make millions of connections between each other, sensory neurons and motor neurons.
What does the axon do
The Axon carries the electrical signal away from the cell body and down the length of
the neuron. The axon is covered with a fatty layer called myelin sheath
This protects the axon and also speeds up the electrical signal. The sheath has gaps called nodes of Ranvier. These make the signal go even faster as it jumps
across each gap.
• At the end of the axon are terminal buttons which communicate with the next neuron in the chain across a gap called the synaptic cleft.
What are the 2 types of neurotransmitters
Excitatory and Inhbitory
Describe excitatory neurotransmitters
+ E.g. adrenaline
+ When bound to receptor sites, creates a positive charge at the postsynaptic neuron
+ Next neuron is likely to fire
+ The signal is sent
Describe inhibitory neurotransmitters
+ E.g. serotonin
+ When bound to receptor sites, creates a negative
charge at the postsynaptic neuron
+ Next neuron less likely to fire
+ The signal is not sent
Describe the synaptic transmission
• An electrical impulse travels along the axon of the presynaptic neuron.
• This triggers the release of neurotransmitters from vesicles at the axons terminal buttons
• These chemical messengers diffuse across the synapse (the gap) and bind with receptor sites on
the dendrites of the postsynaptic neuron.
• Once neurotransmitters bind to the receptor sites, it creates a new electrical impulse to travel
down the postsynaptic neuron.
• Neurotransmitters left in the synapse are broken down by enzymes and re-absorbed into vesicles
to be used again - reuptake
What is Hebbs theory of learning and neuronal growth
When we learn this creates new connections between neuron in the brain
The synaptic connections in the brain become stronger the more they are used (the brain is plastic)
What is engram
An engram is a trace left after learning (this was suggested by Hebb)
Can be made permanent if we continually practise and rehearse.
How does neuronal growth occur
Cell assemblies are groups of neurons that fire together.
The more they fire, the more the synaptic connections grow and strengthen.
Neuronal growth occurs as the cell assemblies rewire to manage new learning.
State 2 strengths of Hebbs theory of learning and neuronal growth
A strength of Hebb’s theory is that it has a scientific Basis. Hebb explained learning in terms of brain function which provided an objective basis for understanding behaviour. And it was an early forerunner to changes in psychology that were to follow such as development of cognitive neuroscience.
This shows that learning can be studied through brain processes.
A strength of Hebb’s theory is it can be applied to education.
He found that rats raised in stimulating settings were better able to find their way through mazes as adults.
Therefore hebb was right about the environment and learning being related. This could be applied to education by creating more stimulating environments to encourage learning.
State one weakness of Hebbs learning and neuronal development theory
A weakness with Hebb’s theory is that it reduces learning to a neuronal level.
This means that other levels of understanding are ignored, such as Piaget’s ideas about how accommodation moves learning forwards. Or how learning is a social activity.
This is an issue as a more complete account of learning would discuss non-biological factors as well.
