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43 Cards in this Set
- Front
- Back
Excitable Cells
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they can change their electrical potential and they use this as a signal to produce some change in cellular activity
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Intracellular fluid
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fluid in cells, cytosol, plus fluid in cell organelles, including nucleus
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Extracellular fluid
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fluid outside the, interstitial fluid and plasma
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Ion
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atom or molecule containing unequal # electrons and protons therefore carrying a net + or - charge
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channel
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small pasage in plasma membrane formed by proteins and certain molecules and ions can diffuse
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Equilibrium potential
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the membrane potential of a specific ion that exists were the forces are equal and opposite (chemical & electrical gradient)
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Chemical gradient
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chemical force=concentration gradient
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current
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movement of electrical charge in biological systems it is achieved by ion movement
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electrical resistance
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the hindrance to electrical charge movement
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membrane potential
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voltage difference between inside and outside of the cell
**Each cell can only have one membrane potential** |
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Are solutions neutral?
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Yes, solutions are neutral and for every cation there is an anion that balances it
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What two conditions must exist for a membrane potential to develop?
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concentration gradient
ion permeability |
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Can we predict the membrane potential when an ion is at equilibrium?
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yes
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Formula for Nernst Equation
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hydrophobic
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non water loving (non soluble in water)
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hydrophilic
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water loving (soluble in water)
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polar
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charged
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non polar
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neutral... balanced charges
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lipophobic
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non lipid loving (non lipid soluble)
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amphipathic
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molecule having polar at one end and non polar on the other end
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lipiophilic
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lipid loving (lipid soluble)
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Is hydrophobic polar or non-polar?
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non-polar ***scared of water... non***
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Is hydrophilic polar or non-polar?
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polar ***polar bears love water**
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Polar region is head or tail of phospholipid?
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"head" ***polar bears have heads**
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Is the non-polar region of a phospholipid the "head" or "tail" region?
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tail **not to mess w/ polar bears tails**
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Describe an integral protein
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amphiphathic, embedded in bilayer and sometimes broken up **integral into**
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Describe a peripheral protein
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non amphipathic, not embedded in phospholipid bilayer (floating right below)
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non-gated channel
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always open
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chemically (ligand) gated channel
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needs chemical messenger to help it through
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mechanically gated channel
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plasma membrane needs to stretch or deform to open
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depolarization
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membrane potential becomes less negative and moves closer to 0
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repolarization
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after membrane potential polarizes it returns to resting level
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hyperpolarization
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when the membrane potential is more negative than the resting level
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overshoot
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reverse of mp polarity, inside is positive in relationship to the outside
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What direction does the membrane potential drift?
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in the direction of that ion's equilibriumn potential
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Another name for leak channels
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non-gated channels
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Voltage gated channels
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need membrane potential to reach a certain level to open
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How many mV when a the voltage gated channel is open & closed?
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Open & Closed
Open = -55 mV (anything larger than about -55 would be open) Closed = -70 mV (Resting potential) |
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When the membrane potential changes (usually positive) what happens?
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the channel changes shape and opens
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What happens after the membrane repolarizes?
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it closes
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threshold
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the point at which an effect begins to be produced (where it starts to open)
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all-or-none
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either the action potentials occure maximally or not at all
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refractory period
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period following the response especially if a muscle or nerve before it recovers capacity to make a second respose
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