Term
| What are the three classes of phospholipids? |
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Definition
| Phosphoglycerides, sphingolipids, and sterols |
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Term
| What is the model that describes how amphipatic molecules behave in the cell membrane? |
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Definition
| Singer-Nicholson fluid-mosaic model |
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Term
| What are two main types of molecules that make up the cell membrane? |
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Definition
| Phospholipids and proteins |
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Term
| What is Fick’s Law of Diffusion and what does it do? |
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Definition
| dS/dt = Px(C1 – C2), describes the passive diffusion of a single substance across a barrier |
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Term
| How do you calculate the permeability constant? |
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Definition
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Term
| What is the Neuron Doctrine? Who proposed it? |
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Definition
| The nervous system is not made of fibers, but rather discreet signaling elements (cells) called neurons, Santiago Ramón y Cajal (Spain) |
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Term
| Who discovered a staining technique for neurons? How does the technique work? |
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Definition
| Camillo Golgi (Italy), impregnating cell with silver grains. |
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Term
| What are the components of a circuit? How are they manifested in the membrane? |
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Definition
| Battery (voltage source) is the source of positive charge, usually the extracellular stimulation, current is the flow of ions, capacitor is the actual membrane, resistors can be membrane and cytoplasm (constant) and channels (variable) |
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Term
| Why does the resting potential exist? |
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Definition
The cell membrane is semi-permeable, and has differing ionic concentrations on the inside and outside
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Term
| What is the name of the equilibrium that helps explain the resting potential? |
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Definition
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Term
| What are the three equations to determine resting potential? |
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Definition
| Nernst equation, Goldman equation, and Ohm's Law |
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Term
| Which one is least accurate, and how does it calculate the resting potential? |
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Definition
| Nernst equation, approximates En as Vm |
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Term
| What is the Nernst equation? |
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Definition
| Fe = Fc, Fe = zFVm, Fc = RT ln([X]out/[X]in), set them equal and solve for Vm |
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Term
| What was the experiment that supported the Nernst explanation of the resting potential? |
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Definition
| Baker, Hodgkin, and Shaw (1961) squeezed our SGA cytoplasm, switched cytoplasm with extracellular fluid, saw Vm reverse back to ~+90 mV |
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Term
| How do you calculate how many charges are needed to cross to develop resting potential? |
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Definition
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Term
| What is the Goldman equation? |
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Definition
| Vm = (RT/F) ln (Ptot[N]o/Ptot[N]i), make sure it is total out on top, total in on bottom |
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Term
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Definition
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Term
| Who was the proponent of the first primitive action potential theory, and what was the theory? |
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Definition
| Bernstein (1917) described an event in which all the channels would open, making the membrane totally permeable, and Vm = 0 mV |
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Term
| Who were the researchers to discovered how the action potential really occurs, and how did they do it? |
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Definition
| Hodgkin, Huxley and Katz experimented on SGA |
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Term
| What are the two general kinds of potentials? |
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Definition
| Graded potentials and action potentials |
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Term
| What are the basic traits of graded potentials? |
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Definition
| Local, decremental, and non-propagating |
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Term
| What are the basic traits of action potentials? |
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Definition
| "All-or-none", non-decremental, and propagating |
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Term
| What does "all-or-none" mean when referring to action potentials? |
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Definition
| Increasing the stimulus to create an action potential does not increase the amplitude of the potenial, it only creates more action potentials |
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Term
| Who invented the patch clamp, and what does it do? |
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Definition
| Neher, Sackmann, and Sigworth, it records measurements of a single channel |
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Term
| How many subunits does the voltage-gated Na+ channel have, and what are they? |
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Definition
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Term
| Which of the Na+ channel subunits is the largest? |
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Definition
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Term
| What is the structure of the α subunit? |
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Definition
| It has 4 transmembrane domains, each of which are made up of 6 transmembrane segments |
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Term
| Which part of the α subunit is responsible for detecting voltage? |
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Definition
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Term
| Who invented the voltage clamp, and what does it do? |
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Definition
| K.C. Cole at Woods Hole, MA, allows experimenter to maintain Vm at a fixed value (Vcom) |
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Term
| What cells produce myelin? |
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Definition
| In the PNS, Schwann cells; in the CNS, oligodendrocytes |
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Term
| What effect does myelin have on resistance and capacitance? |
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Definition
| Capacitance is lowered, resistance is increased |
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Term
| Who used the voltage clamp to illustrate how certain channels behave? |
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Definition
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Term
| Which ion has a higher selectivity through the Na+ channel than Na+? |
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Definition
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Term
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Definition
| A drug or toxin that blocks the normal action of a protein or a biochemical process |
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Term
| What is a receptor agonist? |
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Definition
| A receptor agonist binds to a receptor and mimics the action of the naturally-occurring neurotransmitter |
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Term
| What is a receptor antagonist? |
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Definition
| A receptor antagonist binds to a receptor and blocks (antagonizes) the action of the neurotransmitter |
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Term
| What is the difference between a receptor agonist and a receptor antagonist? |
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Definition
| A receptor agonist mimics the action of the naturally-occurring neurotransmitter, while a receptor antagonist blocks it instead |
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Term
| What is the difference between a receptor antagonist and an inhibitor? |
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Definition
| A receptor antagonist is an inhibitor, but it is a specific kind |
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Term
| What defines whether a synapse is excitatory or inhibitory? |
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Definition
| Excitatory synapses depolarize, while inhibitory synapses hyperpolarize |
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Term
| What is spatial summation? |
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Definition
| Summing of simultaneous (or close to simultaneous) EPSPs and IPSPs from multiple synapses at the axon hillock |
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Term
| What is temporal summation? |
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Definition
| Summing of sequential EPSPs (or IPSPs) to create a single larger EPSP (or IPSP) to be sent to the axon hillock |
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Term
| What is the average amplitude of an EPSP or IPSP? |
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Definition
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Term
| What are the two types of neurotransmitter receptors? |
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Definition
| Ionotropic and metabotropic |
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Term
| What is an ionotropic receptor? |
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Definition
| Receptors that are directly associated with the ion channel, faster and short-lasting |
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Term
| What is a metabotropic receptor? |
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Definition
| Receptors that induce changes in the cell membrane that lead secondarily to changes in ion channels, slower and long-lasting |
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Term
| What is the end plate potential? |
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Definition
| Same thing as a EPSP but in a muscle cell, brings muscle to threshold |
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Term
| What is the reversable potential? |
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Definition
| Vrev is the potential in a muscle cell in which the amount of Na+ flowing in and K+ flowing out is equal, Vrev = 1/2 (EK + ENa) |
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Term
| What is the receptor density of a normal muscle at the neuromuscular plate? |
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Definition
| About 10,000 receptors per μm2 |
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Term
| What happens to receptor density in denervated and hypersensitive muscle? |
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Definition
| The receptor density spreads out across the entire muscle, and is around 1000-2000 receptors per μm2 |
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Term
| What is long-term potentiation and how does it occur? |
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Definition
| LTP makes a neuron more sensitive to inputs as a response to rapid repeated stimulation, it occurs as a result of NMDA receptors responding to higher levels of stimulation |
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Term
| What are trophic effects and how do they occur? |
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Definition
| Trophic effects are long-term effects that do not involve the neurotransmitter, usually occur either by secretion of a substance other than the neurotransmitter, or mediation by the postsynaptic cell |
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Term
| What are the numbers that should be remembered about a typical mammalian muscle cell? |
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Definition
| Vm = -70 mV, EK = -90 mV, ENa = +63 mV |
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