Term
| What is the basis for electrical signaling in the nervous system? |
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Definition
| The ability of the plasma membrane to generate an electron potential |
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Term
| What are the molecules that carry negative charges and are confined within the cell? |
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Definition
| Anions. Generally nucleic acids and proteins. |
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Term
| What are cell membrane channels that are always open known as? |
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Definition
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Term
| What is the electrical potential where equilibrium is reached called? |
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Definition
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Term
| What is the resting membrane potential for most cells? |
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Definition
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Term
| Are there normally more negative charges inside or outside a cell? |
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Definition
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Term
| Where is NA+ in high concentration? |
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Definition
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Term
| Where is K+ in high concentration? |
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Definition
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Term
| What determines the resting membrane potential? |
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Definition
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Term
| What causes Na+ channels to open? |
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Definition
| Increased positive charge in the local environment. |
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Term
| What are channels that respond to increased positive charge in the local environment called? |
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Definition
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Term
| What is the electrical mechanism for carrying signals along membranes rapidly and for long distances? |
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Definition
|
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Term
| What is action potential? |
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Definition
| All or nothing signal that transmits information for long distances. |
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Term
| Where do action potential signals propagate? |
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Definition
| Along the conductile region of neurons in the CNS and PNS and in skeletal muscle fibers. |
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Term
| What inactivates the NA+ voltage-gated channels? |
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Definition
| The movement of the "ball and chain" into the mouth of the channel. |
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Term
| What are K+ voltage-gated channels known as? |
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Definition
| Delayed rectifier channels. |
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Term
| In myelinated axons, what are the only sites where the plasma membrane directly contacts the extracellular fluid? |
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Definition
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Term
| What are the sections between the nodes of Ranvier known as? |
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Definition
|
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Term
| What are internodal regions? |
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Definition
| The regions between the nodes of Ranvier that are wrapped in layers of myelin. |
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Term
| Where are Na+ and K+ voltage-gated channels found in myelinated axons? |
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Definition
| In the plasma membrane of the nodes. |
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Term
| Why is myelin important in myelinated axons? |
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Definition
| It provides a high resistance pathway between the neuronal cytoplasm and the extracellular space. |
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Term
| What is the saltatory conduction? What does the "saltatory" root mean? |
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Definition
| Action potential propagation. Latin for "to hop." |
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Term
| What can action potential propagation velocities reach with saltatory conduction? Nonmyelinated neurons? |
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Definition
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Term
| In an electric wire, current is carried by electrons. What is it carried by in biological systems? |
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Definition
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Term
| What can the plasma membrane be thought of in reference to action potential? |
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Definition
| A resistor. It prevents the passage of ions unless channels are open. |
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Term
| What lays down myelin wrap? |
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Definition
| Oligdendrocytes in the CNS and Schwann cells in the PNS. |
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Term
| What does the influx of Na+ at one node do to the membrane at the next node? |
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Definition
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Term
| In what kind of neurons is the membrane depolarized by opening stretch-activated channels? |
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Definition
| Sensory neurons in the periphery. |
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Term
| What varies the amplitude of generator potentials? |
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Definition
| The intensity of the stimulus. |
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Term
| What is generator potential said to be? |
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Definition
| Graded with the strength of the stimulus. (The stronger the stimulus, the larger the graded potential.) |
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Term
| How do receptor potentials decay? |
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Definition
| Passively- the size of the potential becomes smaller and smaller the farther it spreads from the site of initiation. |
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Term
| When is action potential initiated? |
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Definition
| When the graded potential depolarizes the membrane to the point that threshold is reached. |
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Term
| How many action potentials can be propagated along the axon every second? |
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Definition
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Term
| What do the roots in synapse mean? |
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Definition
| Syn- together, haptein- to clasp. |
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Term
| In what terms are excitation and inhibition defined? |
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Definition
| Whether the membrane potential is driven toward threshold or away from threshold. |
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Term
| What is a site where one neuron communicates to another neuron? |
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Definition
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Term
| What type of synapses are formed by gap junctions? |
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Definition
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Term
| What type of synapses of the CNS are the vast majority? |
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Definition
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Term
| What neuron are neurotransmitters released from? |
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Definition
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Term
| What neuron are neurtransmitters bound? |
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Definition
|
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Term
| What are the purposes of neurotransmitters? |
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Definition
| Excite the cell by admitting cations or inhibit the cell by admitting CL- |
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Term
| What are seven excitatory neurotransmitters? |
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Definition
| Acetylcholine, glutamate, serotonin, epinepherine, norepinepherine, dopamine, and peptides such as endorphins. |
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Term
| What are the two inhibitory neurotransmitters? |
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Definition
| Gamma amino butyric acid (GABA) and glycine. |
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Term
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Definition
| Excitatory postsynaptic potential. |
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Term
| Where is action potential initiated? |
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Definition
|
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Term
| What happens when an action potential arrives at an axon terminal? |
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Definition
| Depolarization opens V-gated CA2+ channels which leads to the fusion of a synaptic vesicle with the plasma membrane. |
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Term
| What are the two main groups of receptors that respond to transmitters (ligand-gated channels)? |
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Definition
| Directly gated channels and second messenger mediated channels. |
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Term
| What does the most common directly gated channel in the CNS respond to? |
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Definition
| The amino acid glutamate. |
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Term
| What channels must bind two molecules of neurotransmitter before the channel can open? |
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Definition
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Term
| What is a characteristic of the directly gated channels? |
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Definition
| They respond quickly; within a matter of a millisecond or less. |
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Term
| What do excitatory neurotransmitters allow through by opening directly gated channels? |
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Definition
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Term
| What do inhibitory transmitters allow through by opening directly gated channels? |
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Definition
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Term
| What does the influx of NA+ produce? |
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Definition
|
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Term
| What does the influx of CA- produce? |
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Definition
|
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Term
| What determines the type of response to a transmitter? |
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Definition
| The type of receptor that is incorporated into the post synaptic membrane. |
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