AP conduction and axons/dendrites

when does positive charge run down the inside of the axon?

when the axon is wide

when does positive charge go across the axonal membrane?

when the axon is narrow

the larger the axonal diameter…

the increase in action potential conductance velocity

what affects axonal excitability?

axonal size and the number of voltage gated channels

what do smaller axons require?

greater depolarization to reach threshold

saltatory conduction

myelin sheath insulates the electrical signals and allows action potential to spread further and quicker

what do schwann and oligodendroglial cells do to the Na+ channels in myelin sheath?

make them concentrated in the nodes of ranvier

what parts of the neuron do not generate sodium dependent action potentials?

dendrites and the neuronal cell body

what is considered the spike initiation zone in neurons?

axon hillock

spike initiation zone

area where action potentials can occur closest to the soma

what does the depolarization of dendrites/soma lead to generation of APs?

only if the axon hillock is depolarized beyond threshold

where does the spike zone occur?

near sensory nerve endings