neuronal communication Flashcards
what are neurons made up of?
cell body (with nucleus) with a long axon and shorter branching dendrites
what do neurons do?
receive, integrate, conduct, and transmit (or not) signals
what is membrane potential?
difference in [ion] on the different sides of membrane (ranges form -40 to -70)
what is depolarization?
membrane potential becoming less negative
what is hyperpolarization?
membrane potential becoming more negative
how do cells read signals?
through voltage changes
what do excitatory signals do?
open cation channels to depolarize
what do inhibitory signals do?
open Cl- or K+ channels to suppress depolarization
what is the purpose of delayed K+ channels?
they open in response to depolarization to enable repolization
they have slower kinetics and cause travelling action potential
what happens to electric signals in the neuron?
they propagate through the neuron until it reaches snyapse
what is the myelin sheath?
acts as electric insulator around axon to increase speed of action potential
what is the differences between chemical and electric synapses?
chemical synapses have synaptic cleft, neurotransmitters and receptors, and are more common
electric synapses have gap junctions, no neurotransmitters, and are faster
what are nuerotransmitters?
small molecules that go from presynaptic neuron (at chemical synapse) to rely signal to post-synaptic neuron
how are neurotransmitters transmitted?
there is action potential at presynaptic site
depolarization of membrane opens voltage-gated Ca2+ channels
Ca2+ influx triggers exocytosis of neurotransmitters
neurotransmitters diffuse rapidly across synaptic cleft and triggers electrical change in post-synaptic cell by binding and opening ligand-gated ion channel
how do you increase Ca2+ in nuerons?
through fluorescent Ca sensors
