neuron function part 1 Flashcards
(40 cards)
What does the CNS consist of?
Brain and spinal cord
What does the CNS contain?
neurons and glia
Approx amount of nerons and synapses in brain
10^11 neurons
10^14-10^15 synapses
What are the four functional zones?
Signal reception
signal integration
signal conduction
signal transmission occurs at the synapse
What is signal reception?
where and how
dendrites and the cell body (soma)
incoming signal received and converted to change in membrane potential
Signal integration:
where and how
Axon hillock- signal is converted to an action potential
signal conduction
where and how
axon (some with myelin)
AP travels down axon
Signal transmission occurs where?
Occurs at synapse
axon terminals
release of NT
all neurons have what?
A resting membrane potential that is negative
What is depolarization
membrane become more positive
What is repolarization
membrane returns to resting value
what is hyperpolarization?
membrane becomes more negative than resting
What is membrane potential determined by?
by relative permeabilities of its membrane to specific ions
transmembrane concentration gradients of these ions
Resting membrane potential counteracts what?
the chemical gradient of ions so there is no net movement of ions across membrane
leak channels are what?
Always open allowing a specific ion to travel though
non gated and selective
when you have equal concentrations of ions across the cell what with the resting potential be?
0
For every ATP hydorlized how many Na and K exchanged
3Na+ ions are transported out
2K+ ions are imported into the cell
What does electrogenic do?
produces a current
what is the resting potential created by?
leak channels
What maintains the concentration gradients of na K?
Na/K ATPase
Ion gated channels:
How do neurons depolarize of hyperpolarize?
By selectively altering permeability
When do gated ion channels open or close?
in response to a stimulus ex. voltage or NT
Channels only allow what to pass though?
Specific ions to pass though the membrane
ions move down electrochemical gradient
As permeability to a specific ion increase what happens?
membrane potential will approch that ion’s equilibrium potential (Nerst equation)
