Neural introduction Flashcards
What 4 processes does the nervous system need to carry out
sense
process - distinguish between relevant/not
react
memorise - adapt i.e. habituation, LTP, LTD
How is an action potential described
Fixed size
All or nothing
What sort of channels does an action potential open
Cation permeable
What happens when a threshold is reach in an AP
Sufficient VG Na+ channels open
Permeability/conductance to Na+>K+
What phase follows threshold in AP
Rising phase Depolarisation Na+ into neurone down electrochemical gradient Shifts Vm -->ENa Vm = positive
What phase follows rising phase in AP
Overshoot
Vm = above zero approx. +40mV
What phase follows overshoot phase in AP
FALLING PHASE Repolarisation VG Na+ close VG K+ open Perm/conductance K+> Na+ K+ diffuses out of neuron down conc grad Vm --> Ek
What phase follows falling phase in AP
Undershoot Hyperpolarisation below resting Vm Vm --> Ek VG K+ add to resting K+ mem perm
When does undershoot wear off
As VG K+ close
Why is conduction unidirectional despite Na+ diffusing in both ways
VG Na+ closed and inactive behind
Membrane needs to hyperpolarise first
Cannot depolarised
Area where an AP cannot be depolarised is called
Refractory period
How is an AP conducted
Non-decremental manner
Max speed of an AP
10m/s
What occurs at synapses
Docking of NT
where does docking occur
At active zone of terminal membrane before an AP
