Neurons and synaptic transmission Flashcards
What are neurons?
Cells specialised to carry neural information throughout the body
What are the 3 types of neuron?
Motor, sensory and relay
What is the distinguishing factor of a relay neuron?
It is not myelinated
What is the distinguishing factor of a sensory neuron?
Its cell body is off to the side
What is the distinguishing factor of a motor neuron?
It is connected to a muscle
What do sensory neurons do?
Carry nerve impulses from sensory receptors to the CNS
What do relay neurons do?
Allow sensory and motor neurons to communicate
What do relay neurons coordinate?
A response
What do motor neurons do?
Conduct nerve impulses from the CNS to effectors
Give 2 examples of effectors.
Muscles and glands
What is the myelin sheath?
An insulating layer around the axon
What is synaptic transmission?
The process by which a nerve impulse passes from the pre-synaptic neuron to the post-synaptic neuron
What is a synapse?
The gap between neurons
When a nerve impulse arrives at a presynaptic neuron, what does it trigger?
An influx of calcium ions
What does the influx of calcium ions stimulate during synaptic transmission?
Vesicles to move to the presynaptic membrane
What do vesicles contain in presynaptic neurons?
Neurotransmitters
What happens when vesicles bind to the presynaptic membrane?
The neurotransmitters diffuse across the synapse
What do neurotransmitters bind to on the postsynaptic membrane?
Receptor sites
What are neurotransmitters?
Chemical messengers that carry signals across a synapse
What are the 2 types of neurotransmitters?
Excitatory and Inhibitory
What do excitatory neurotransmitters do?
Increase the likelihood of a neuron firing
Give an example of an excitatory neurotransmitter.
Dopamine
What do inhibitory neurotransmitters do?
Decrease the likelihood of a neuron firing
Give an example of an inhibitory neurotransmitter.
Serotonin
What is an EPSP?
A postsynaptic potential that makes the postsynaptic neuron more likely to fire an action potential
What is an IPSP?
A postsynaptic potential that makes the postsynaptic neuron less likely to fire an action potential
What is summation?
The net result of IPSPs and EPSPs firing at the same time
What are the 2 types of summation?
Spatial and temporal
What is spatial summation?
When nerve impulses are generated in the postsynaptic neuron from multiple presynaptic neurons
What is temporal summation?
When a large number of nerve impulses are generated at the postsynaptic neuron due to rapid firing of the same presynaptic neuron
