nervous system: neurons Flashcards
what are the 5 general characteristics of neurons
- excitability
- conductivity
- secretion
- extreme longevity
- amitotic
what is excitability of a neuron
responsiveness to a stimulus
what does stimulus do to the membrane
causes a local electrical change in rmp by initiating the movement of ions across plasma membrane
what are the local electrical changes in an excitable cell called
graded potentials
describe conductivity of a neuron
it involves an electrical change that is propagated along the plasma membrane as voltage-gated channels open during an action potential (move)
what do neurons secrete
neurotransmitters in response to conductive activity
how do neurons exhibit extreme longevity
most neurons formed during fetal development are still functional in elderly adults
describe the amitotic characteristic of a neuron
neurons lose the ability to form new cells through cell division during fetal development
what does the cell body of the neuron houses
organelles
what is the name of the cytoplasm of the neuron
perikaryon
what is a distinctive feature of the organelles in a neuron
large number of ribosomes
what transmits graded potentials along its plasma membrane to axon
cell body of neuron
describe the appearance of dendrites
relatively short, small tapering processes that branch off the cell body
are dendrites insulated with myelin
no
what is the role of dendrites
receive input for neuron
