synapses Flashcards
what is a synapse
junction between two neurons that transmit an impulse chemically via neurotransmitters
when the action potential reaches the pre synaptic neuron what does it cause
voltage gated calcium ion channels to open
when calcium ion channels open, where do they move to
calcium ions diffuse into the pre synaptic neuron down their electrochemical gradient
what do the calcium ion channels opening trigger
causes synaptic vesicles containing neurotransmitter to move and fuse with pre synaptic membrane via exocytosis and diffuses across to post synaptic membrane
what neurotransmitter is commonly used in synapse communication
acetyl choline
what does ACH do when it has been released
binds to a receptor on post synaptic membrane which causes sodium ion channels to open
why do sodium ion channels open when a neurotransmitter binds with a receptor
to trigger a new action potential
what is summation
the idea that a new action potential is only triggered if neurotransmitters have built up to the threshold level
what is spatial summation
MULTIPLE pre synaptic neurons release neurotransmitter to trigger a new action potential in ONE post synaptic membrane due to high neural input
what is temporal summation
high frequency of action potentials reaches ONE pre synaptic neuron causing high concentrations of neurotransmitter to trigger an action potential