Synaptic transmission Flashcards
Simply put, what is synaptic transmission?
The process by which one neuron communicates with another.
What causes an electrical impulse to be created?
An action potential.
What is the resting state of a neuron cell?
Negative charge.
When does an action potential occur?
When a stimulus activates the neuron, disturbing the negative charge.
How is information passed down the axon of a neuron?
As an electrical impulse known as an action potential.
What happens when the action potential reaches the end of the axon?
It must be transferred to another neuron or tissue.
What is the space between the pre-synaptic neuron and the post-synaptic neuron?
The synaptic cleft.
Where are synaptic vesicles found?
In the axon terminals (at the end of the neurons).
What are held in the synaptic vesicles?
Chemical messengers, known as neurotransmitters.
What happens when an action potential reaches the axon terminal?
Synaptic vesicles release their neurotransmitters.
Where is the final point which an action potential reaches before the vesicles are released?
The synaptic terminal of the pre-synaptic neuron.
What happens when neurotransmitters reach the post-synaptic neuron?
They bind to receptors on the neuron’s membrane.
Do the vesicles cross the synaptic cleft?
No, they release the neurotransmitters into the gap but remain on the pre-synaptic neuron.
How do the neurotransmitters cross the synaptic cleft?
They diffuse across and bind to receptors.
What effect does an inhibitory neurotransmitter have on the post-synaptic neuron?
They reduce the likelihood that the post-synaptic cell will fire.
What are the two types of neurotransmitter effects on the post-synaptic neuron?
Excitatory and Inhibitory.
What type of neurotransmitter is noradrenaline?
Excitatory.
What type of neurotransmitter is GABA?
Inhibitory.
What effect does an excitatory neurotransmitter have on the post-synaptic neuron?
They make the post-synaptic cell more likely to fire.
Outline the process of synaptic transmission: (4)
- The neuron is activated by a stimulus.
- An action potential occurs creating an electrical impulse.
- The impulse travels down the axon to the synaptic terminal.
- Triggering vesicles filled with neurotransmitters to be released into the synaptic cleft.
- Neurotransmitters reach the receptors on the post-synaptic neuron.
- Signalling for an electrical impulse to be released.
What triggers an action potential (electrical impulse) in the post-synaptic neuron?
The binding of neurotransmitters to the receptors on the post-synaptic membrane.
What happens to the neurotransmitters left in the synapse?
They are taken back by the pre-synaptic neuron, or are broken down by enzymes.
What is meant by the term neural networks?
Groups of neurons communicating with each other.
What is the synapse?
A small gap between each neuron in a neural network.
How are signals transmitted WITHIN neurons?
Electrically, through an action potential.
How are signals transmitted BETWEEN neurons?
Chemically, through neurotransmitters diffusing across the synaptic cleft.
What part of the post-synaptic neuron is involved with synaptic transmission?
The dendrites receive the neurotransmitter signals.
Where is the chemical message (from neurotransmitters) converted into an electrical message (action potential)?
In the dendrites of the post-synaptic neuron.
The fit of a neurotransmitter into a receptor has been likened to a lock and key fit such as an enzyme, explain why?
Each neurotransmitter has a specific molecular structure that fits perfectly into a post-synaptic receptor site.
Which neurotransmitter is found where a motor neuron meets a muscle and when released causes a muscle to contract?
Acetylcholine (ACh).
What type of neurotransmitter is seratonin?
Inhibitory.
Adrenaline is both a hormone and a neurotransmitter, what type of neurotransmitter is it?
Excitatory.
Suggest the effects of anti-anxiety medications such as Valium:
They are inhibitory to reduce the chance of firing.
