Synaptic Transmission- Excitation, Inhibition And Summation Flashcards
(11 cards)
What is synaptic transmission?
The process by which one neuron communicates with another across a synapse using chemical neurotransmitters.
What is the role of a neurotransmitter in synaptic transmission?
Neurotransmitters are released from the presynaptic neuron, travel across the synaptic cleft, and bind to receptors on the postsynaptic neuron to either excite or inhibit a response
Define excitation in terms of synaptic transmission.
Excitation occurs when a neurotransmitter increases the likelihood that the postsynaptic neuron will fire an action potential by depolarising the neuron
What effect does an excitatory neurotransmitters increase have on a postsynaptic neuron?
It causes depolarisation by allowing positively charged ions (e.g Na+) into the neuron, making it more likely to reach the threshold and fire.
Give an example of an excitatory neurotransmitters?
Noradrenaline
Define inhibition in terms of synaptic transmission?
Inhibition occurs when a neurotransmitter decreases the likelihood that the postsynaptic neuron will fire an action potential by hyperpolarising the neuron
What effect does the inhibitory neurotransmitters increase have on a postsynaptic neuron?
Give an example of an inhibitory neurotransmitter?
Serotonin
What is summation in the nervous system?
Summation is the process by which the effects of multiple excitatory and/or inhibitory inputs are added together at the postsynaptic neuron to determine if it will fire
What will happen if the total effect of summation does not reach the threshold?
The postsynaptic neuron will not fire an action potential
What happens if the total effect of summation does reach the threshold?
The postsynaptic neuron will fire an action potential and the signal continues along the neural pathway.
