Term
| What is the role of sodium-potassium ATPase? |
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Definition
| maintain sodium/potassium gradient |
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Term
| What is the role of calcium ATPase? |
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Definition
| maintain calcium gradient |
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Term
| What is the role of proton ATPase? |
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Definition
| maintain pH & proton gradient |
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Term
| Ion exchangers use _____ as energy to move ions |
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Definition
| chemical gradients (mainly sodium) |
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Term
| What is the role of the sodium/calcium exchanger? |
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Definition
| maintain low intracellular calcium |
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Term
| What is the role of the sodium/hydrogen exchanger? |
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Definition
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Term
| What kind of calcium is removed thanks to the sodium/calcium exchanger? |
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Definition
| calcium that enters during activity (ex. calcium that enters due to action potentials) |
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Term
| What kind of calcium is removed thanks to calcium ATPase? |
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Definition
| calcium that "leaks" into the cell |
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Term
| What do the sodium/calcium exchanger & calcium ATPase have in common? |
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Definition
| both keep intracellular calcium concentrations low |
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Term
| Does the sodium/calcium exchanger or the calcium ATPase move more calcium? |
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Definition
| sodium/calcium exchanger (more numerous than ATPase which counteracts its lower affinity) |
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Term
| Is the gradient for calcium highly or loosely regulated? |
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Definition
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Term
| Why is it important to keep intracellular calcium levels so low? |
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Definition
| transient increases in intracellular calcium act as a signal to regulate neural function (any calcium that comes in is easily detected by calcium binding proteins in the cell) |
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Term
| 5 main effects of calcium in the cell |
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Definition
1. regulate electrical activity of neuron via sodium & potassium channels
2. stimulate neurotransmitter release
3. modification of synaptic strength
4. regulate metabolic activity & cell growth
5. implicated in cell death |
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Term
| What is the role of the sodium/calcium exchanger? |
|
Definition
| keep intracellular calcium very low |
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Term
| The sodium/calcium exchanger exchangers _____ sodium for _____ calcium |
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Definition
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Term
| What is the electrogenic nature of the sodium/calcium exchanger? |
|
Definition
| one extra positive charge |
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Term
| Is the sodium/calcium exchanger reversible? |
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Definition
| yes! direction of calcium movement depends on membrane voltage & equilibrium potential for calcium & sodium |
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Term
| What is the main thing to remember when doing calculations using calcium? |
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Definition
| you need to use the valence of two!! |
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Term
| Where does the energy come from for the sodium/calcium exchanger? |
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Definition
| the amount of charge that crosses the membrane |
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Term
| For the sodium/calcium exchanger, what does it mean when 3 x sodium driving force = 2 x calcium driving force? |
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Definition
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Term
| For the sodium/calcium exchanger equation, if Vm < Vo what happens? If Vm > Vo? |
|
Definition
Vm < Vo --> sodium enters the cell (calcium is being excreted)
Vm > Vo --> sodium leaves the cell (calcium is entering |
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Term
| Where is the energy driving the sodium/calcium exchanger pump coming from? |
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Definition
| the exchanger is powered by the concentration gradient on sodium (but the calcium concentration gradient also has an effect!) |
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Term
|
Definition
| carry multiple ions in the same direction across the membrane |
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Term
| Co-transporters primarily regulated _____ levels in the neuron |
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Definition
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Term
| When do chloride co-transporters use the sodium gradient for energy? |
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Definition
| to bring chloride into the cell |
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Term
| The sodium/chloride co-transporter brings in _____ sodium & _____ chloride |
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Definition
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Term
| The sodium/potassium/chloride co-transporter brings in _____ sodium, _____ potassium, & _____ chloride |
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Definition
| 1 sodium, 1 potassium, 2 chloride |
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Term
| When does the chloride co-transporter use the potassium gradient for energy? |
|
Definition
| to move chloride out of the cell |
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Term
| Chloride regulation is important for _____ |
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Definition
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|
Term
| All chloride transport systems are electrically _____ |
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Definition
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Term
| 5 ions that we learned about pumps maintaining their concentration gradients |
|
Definition
1. sodium
2. potassium
3. calcium
4. chloride
5. hydrogen |
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|
Term
| 2 possible sources of energy for pumps |
|
Definition
1. ATP
2. chemical gradients |
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|
Term
|
Definition
1. ATPases
2. exchangers
3. co-transporters |
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|
Term
| _____ pumps influence membrane potential |
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Definition
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|
Term
|
Definition
| slow! 100's of ms to a few seconds |
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