L03: Neuronal Excitability Flashcards
Which ion acts to create depolarisation
Sodium
What happens to sodium during depolarisation
Influx
What happens during repolarisation
Potassium influx
Sodium channels are terminated
What type of ion channel causes action potential
Voltage-gated ion channel
What is the stimulus that opens voltage gated ion channels
Depolarisation
What is the stimulus that closes voltage gated ion channels
Repolarisation
What are the types of voltage gated ion channels
Sodium voltage gated ion channel
Potassium voltage gated ion channel
What has to be met for depolarisation to occur
Threshold value
What happens to the channels when the threshold value is met and depolarisation occurs
Voltage acted sodium channels open
Sodium influx occurs
Conductance of channel increases
Action potential reaches at +40mv
What happens during depolarisation
Sodium channels become inactivated and sodium influx stops
Repolarisation causes Voltage gated potassium channels to open
Potassium efflux occurs
Voltage gated potassium channels remain open which causes hyperpolarisation
Voltage gated potassium channels close
Resting membrane potential is reached
What is a refractory period
The time that is impossible to create a 2nd action potential straight after the 1st one
What are the 2 types of refactory period
Absolute
Relative
What is the absolute refractory period
Action potential cannot occur
What is the absolute refractory period
Action potential can occur but a bigger stimulus is required
What are the status of channels during the absolute refractory period
Potassium channels are open
Sodium channels are inactivated
