Neurophysiology 1 Flashcards
Chemically gated ion channels stimulus
Chemical neurotransmitter bind to ion channel
Chemically gated ion channel closes how?
The neurotransmitter unbinds causing the channel to close
Voltage gated ion channels stimulus
Membrane depolarizes to threshold voltage (-60mV)
Voltage gated ion channels closes how?
Membrane threshold changes causing channel to inactivate and close
Mechanically gated ion channel stimulus
Deformation of membrane (eg stretch or squish)
Mechanically gated ion channel closes how?
When membrane returns to original shape the channel closes
Where are chemically gated Na+ and K+ channels on a neuron?
Dendrites and cell body
Where are voltage gated Na+ and K+ channels on a neuron?
Axon hillock and axon
Where are voltage gated Ca2+ channels on a neuron?
Axon terminals
What is a local potential?
A change in membrane potential voltage at a localized area of the dendrite or cell body membrane
How does a local potential occur?
Neurotransmitter binds to and opens chemically gated ion channels on dendrites/cell body and allows ions to move in or out
Local potentials can be either…
Excitatory or Inhibitory
Depolarization
Membrane becomes more positive
Hyperpolarization
Membrane becomes more negative
How do EPSPs form?
A presynaptic neuron releases excitatory neurotransmitter, and when neurotransmitter binds, it opens chemically gated Na+ channels, Na+ enters post synaptic cell, causing depolarization (membrane becomes more positive)
