Glossary of COGS 107B

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how does myelin affect the conduction of electrical signals (current)?
1. it decreases the capacitance, thereby speeds up conduction
2. it creates greater membrance resistance leading to less leaking of current. Thus, increasing the current's length constant.
what is capacitance good for in the context of electrical signaling in neurons?
it leads to temporal summation of EPSPs
what is the sodium potassium pump?
it is a protein that moves 3 Na+ ions out of the cell and moves 2 K+ ions into the cell (against their concentration gradient)
What causes the resting potential?
the separation of charges across the membrane
What do the resistors correspond to in a membrane?
channels mainly
What is the Nernst Potential?
It is the potential when the electrical force driving the ion into the cell exactly balances the chemical force driving the ion out of the cell.
Bigger axon means (more/less)
a. capacitance
b. longitudal resistance
c. membrane resisistance
a. more (greater surface which can store charge)
b. less
c. less (more ion channels)
what does the capacitor correspond to in a membrane?
a patch of lipid bilayer w/out channels
what happens to the membrane/input resistance of a neuron if you increase the size of a neuron?`
you are decreasind the input resistance because there are more resting channels to conduct ions (so that current can flow into the nueron more easily)
What do voltage-gated ion channesl detect?
changes i nmembrne potential
How does an increase/decrease in capacitance affect the speed of current conduction?
increase in capacitance slows down current conduction
K+ will tend to diffuse from _________ the cell to __________ the cell.
inside; outside
What happens to the capacitance of a neuron if you increase its surface area?
capacitance goes up
why is the action potential useful in signaling?
long distance communication
Which parts of a neuron has resistance?
axon and membrane
What happens if we put a bunch of a K+ outside a cell when the cell is at resting potential?
it should lead to an influx of K+ into the cell because the electrostatic positive force outside the cell will surpass the electrochemical force trying to push the K+ out of the cell
what is the membrane for?
separating the charge so that during depolarization, an AP can be generated
what is the Nernst potential for: a. K+ b. Na+ c. Cl-
a. -75mV
b. +55 mV
c. -60mV
what do ligand-gated ion channels do?
they are sites for NT binding

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