Nervous System Flashcards
Action Potential (AP)
short lasting event where eletrical potential of membrane rapidly rises and falls following a consistent transjectory
transjectory is when nueron sends info. down axon, away from cell body
how is this transjectory caused
by exchange of ions across neuron membrane
Frequency Of AP’s depends on
how far membrane potential is above threshold
Saltatory conduction
action pot jumps from node of ranvier to the next on a myelinated axon
Spatial summation
addition of graded potential spaced out
Occurs when they are stimulated more of, less simultaneously
Ie. Generated at diff. locations
temporal summation
Several ESPS occur on the same 1 neuron
graded potential cant dissipate at one time and combine EPSP summate
Excitatory
- depolarisation
- tf closer to threshold to generate AP
Inhibitory
membrane potentail hyperpolarised or stable
tf less likely to fire AP
EPSP (Excitatory postsynaptic potentials)
graded depolarisation caused by nuerotransmitter binding to receptors on postsynaptic neuron
causes small opening of. cation channels (Na+ / K+ IN/OUT)
inhibitory postsynaptic potentials IPSP
same but w hyperpolarization
Graded potential
small changes in potential membrane that occur when ion channels open or close in response to a stimulus.
ie.binding of a neurotransmitter to receptors
magnitude of the potential change varies with
strength of stimulus
How sensory information is perceived
“All or nothing law”
once threshold is reached, nothing more can happen
3 modalities of stimulus
type -coded by receptor
location-coded by receptor feild
intensity-frequency of AP in n ueron , number of receptor activated
Lateral inhibition
enhances contrast between areas of strong. and weak stimulus
