Physiology of Neurons Flashcards
What is spatial summation?
The sum of signals that a neuron receives from multiple other neurons that synapse onto it.
This allows many small depolarisations to be able to reach threshold.
The signals can be excitatory and they can be inhibitory.
What is temporal summation?
When the input neuron is firing fast enough for the receiving neuron to be able to reach threshold.
This occurs when the receiving neuron’s ability to recover from depolarisation is slow enough to allow the inputting neuron to fire multiple signals.
What does excitability mean?
How easy it is to start nervous signalling (sensitivity in sensory cells and irritability in muscle cells).
If the threshold is increased, the excitability is lowered.
What is Lidocaine?
A topically applied local anaesthetic which works by blocking Na+ channels in nociceptors.
This reduces their excitability because the threshold potential gets raised
What is another name for Lidocaine?
Lignocaine
What type of drug is carbamazepine?
An anti-convulsant
What is an example of a class 1 anti-arrhythmic drug?
Quinidine
How does Carbamazepine work?
Inactivates Na+ channels, raising the AP threshold and therefore reduces its excitability.
How do class 1 anti-arrhythmic drugs work?
Lower the conduction velocity which extends the refractory period.
