Membrane potentials Flashcards Preview

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Flashcards in Membrane potentials Deck (24)
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1
Q

membrane potential

A
  • the difference in electric potential between the outside and inside of the cell
    • usually -50 to -70
2
Q

Nerst potential

A
  • the cell membrane potential when the ion of reference no longer wants to move
    • chemical gradient equals electrical gradient
3
Q

Nerst equation

A

E = 61 * log [Ko]/[KI]

answer in mV

4
Q
A

measuring the electrical flow of sodium through a channel. rises in the graph are when the channel is open

5
Q

voltage gated channel

A

opens when the cell potential reaches a certain voltage

6
Q

ligand-gated channel

A

opens when a ligand adheres to channel

ex. G protein coupled receptor

**can be intracellular or extracellular

7
Q

mechanically gated channel

A

opens when physically opened

Ex: by touch or vibrations for hearing

8
Q

Goldman-Hodgkin-Katz equations

A

E = -61 * log (CNai*PNa+Cki*PK+CClo*Pcl) / CNao*PNa+CKo*PK+CCli*PCl

9
Q

conductance

A

permeability

10
Q
A
  • Na
    • Activation gate is voltage sensitive
    • Inactivation “gate” is time sensitive
  • K
    • Activation gate is voltage sensitive
    • same gate closes based on voltage change
  • Na gate being inactive is what forces the potential to go in one direction
11
Q

Absolute refractory period

A
  • no action potential can be generated
    • Na gate is inactivated
12
Q

Relative refractory period

A
  • action potential can be stimulated, but will require stronger stimulus
13
Q

dendrites

A

Extension of the nerve cell that receives messages from other cells

  • signals received result in changes in local membrane potential
  • All the dendrites receive signals that hyperpolarize or depolarize, eventually the entire neuron will get enough depolarization to initiate an action potential at the axon hillock and is send down the axon to synapses with other neurons and muscle cells.
14
Q

axon hillock

A
  • last spot where the membrane potentials are summed up before being translated to the axon
15
Q

acetylcoline

A

neurotransmitter

16
Q

hyperpolarizers

A

Cl-

K+ (leak channel)

17
Q

depolarizers

A

Na+

Ca++

18
Q

SSRIs

A

slow the re-uptake of seratonin (neurotransmitter) so it has a longer affect

19
Q

Excitatory vs inhibatory fibers

A
  • There are more excitatory neurotransmitters
  • the inhibitory get used more
20
Q
A
  • inhibatory fibers can either attach directly to the excitatory fiber
  • or attach to the neuron nearer to the Axon Hillock
21
Q

schwann cells

A

cell that provides the myelin sheath around the neuronal axon

22
Q

oligodendrocytes

A

provide myelin sheath for axons in central nervous system

23
Q

node of ranvier

A

gap in myelin sheath between schwann cells that allows for saltatory conduction and allows signal to move faster

24
Q

size and myelination vs velocity of signal

A
  • bigger and mylenated axons move signals faster
  • smaller unmyelinated fibers move slower