Physiology - Neuro III (Lec6)
About this set
Created by:
dakotadll on April 1, 2009
Classes:
CCRI Human Physiology 2013, Physiology CCRI (Knight)
Log in to favorite or report as inappropriate.
Order by
47 terms
Terms | Definitions |
|---|---|
 threshold potential | Depolarization must reach the ___ ___ for A.P. to occur |
| threshold stimuli | The stimuli that is just strong enough to reach the threshold potential is called ___ ___. |
| number, frequency, A.P. | The brain distinguishes the intensity by ___ and ___ of ___. There is a limit to the frequency of A.P's that can be generated. |
| can not, absolute refractory period | During an A.P. a second stimulus ___ ___ produce a second A.P., the membrane is in the ___ ___ ___. |
| absolute refractory period, relative refractory period | Following __ __ __ there is a period when a second A.P. can be generated but the stimulus strength has to be much greater than usual, this is the ___ ___ ___ |
| voltage-gated Na+ | High number of ___-___ ___+ channels in the axonal membrane is why A.P's can travel along distances and don't fade out. |
| Action potential propagation | ___ ___ ___ is when a new A.P. produces local currents of its own. |
| depolarizes | A.P. propagation - new A.P. produces local currents of its own which ___ the region adjacent to it, producing another A.P. at the next site, and so on. |
| domino, strength | A.P. propagation - like a ____ effect, it creates its own A.P. each membrane charge is all the same ____. |
| Na+, K+ | A.P. propagation - there is a sequential opening and closing of __ and __ channels along the membrane. |
| refractory, away from | Because membrane areas that have just undergone an A.P. are ___, the only direction of an A.P. is ___ ___ region that just undergone one. |
| refactory period | ___ ___ ensures that the A.P. signal only travels in one direction. |
| Myelin, leakage | ___ is an insulator that prevents ___ in a graded potential, allowing it to spread further. |
| low | Concentration of voltage-gated Na+ channels in myelinated region of axons is ___.(low or high) |
| nodes Ranvier, high | A.P.'s occur only at the ___ of ___ (where concentation of Na+ channels is ___). |
| saltatory conduction | A.P.'s literally jump from one node to the next as they prpoogate along myelinated fiber. Called ___ ___ (hint: 2nd word think of leader of a band) |
| less, myelin | Propagation via saltatory conduction is faster because ___ charge leaks out through ___- covered areas. |
| more, action potential | Saltatory conduction, ___ charge arrives at the node adjacent to the active node, and ___ ___ is generated there sooner. |
| speed efficiency, thinner | Myelinated fibers add ___ and ___ and saves room in the nervous sytem because axons can be ___ |
| convergence | ___ : many synapses from many different presynaptic cells affect a single postsynaptic cell; allowing information from many sources to influence a cell's activity. |
| divergence | ___: When a single presynaptic cell affects many postsynaptic cells; one information source affects multiple pathways. |
| synaptic vesicles, synaptic cleft | In the axon terminal, the ___ ___, containing neurotransmitters, empty into the ___ ___. |
| receptors | The neurotransmitters then bind to ___ on the postsynaptic cell (typically a dendrite). |
| postsynaptic density | The postsynaptic membrane has a high density of membrane proteins that make up the ___ ___. |
| synaptic, chemical synapses | The ___ cleft prevents direct propagation of the current from pre to post. ___ ___ operate in one-way conduction of A.P.'s. |
| Na+ channels | Neurotransmitters attach to receptors which trigger ___ ___ in the postsynaptic density to open. |
| electrical synapses | ___ ___ allow currents from presynaptic cell to flow directly through gap junctions to postsynaptic cell, initiating action potentials. |
| cardiac, smooth | Electrical synapses are very rapid and numerous in ___ and ___ muscle. Rare in mammalian nervous sytems. |
| chemical synapses | Electrical synapses are the opposte of ___ ___. |
| voltage gated, terminal | Step 1: AP moving along axon's ___-___ Na+ and K+ channels arrives at axon ___. |
| Ca++ | Step 2: At axon terminal, AP opens voltage-gated ___ channels. |
| Ca++, neurotransmitters | Step 3: An influx of ___ triggers the release of ___ into the synaptic cleft. |
| receptor | Step 4: The binding of neurotransmitters to ___ proteins in the postsynaptic membrane is linked to an alteration in it's ion permeability. |
| Na+, Na+ | The neurotransmitters bind to the ___ channels and opens the channels up to more ___ |
| excitatory synapse | ___ ___: the postsynapse response to the neurotransmitter is a depolarization, bringing the membrane potential closer to threshold. |
| Na+, K+ | With excitatory synapse, postsynaptic membrane channels are opened to ___, ___ and other small (+) ions. |
| excitatory postsynaptic potential | The "net" movement of (+) ions "into" the postsynaptic cell (slight depolarization)....this potential change is called an ___ ___ ___ |
| graded, action potential | An EPSP is a ___ depolarization that moves the membrane potential closer to the threshold for firing an ___ ___ (excitement). |
| excitable, neuron, muscle | ___ refers to a cell that responds to stimuli by generating an electrical signal at the cell membrane. ___ and ___ cells are excitable. |
| depolarization, excitable | EPSP: a local, graded, ___ of an ___ cell. Function is to generate an action potential in the postysnpatic cell. |
| hyperpolarizing, inhibitory postsynaptic potential | At inhibitory synapses, the potential change in the postsynaptic neuron is generally a ___ graded potential called an ___ ___ ___ |
| lessens | Activation of an inhibitory synapse ___ the likelihood of an A.P. |
| opened, hyperpolarization | In IPSP Na+ channels are never ___ (opened or closed), only K+ and Cl-. Cl- entering and K+ leaving causes ___. |
| grand postsynaptic potential | The ___ ___ ___ composite of all EPSP's and IPSP's occuring at the same time. |
| refractory | Graded potentials have no ___ period, they can have an additive effect when stimulated more than once. |
| temporal summation | ___ ___ is the summing of several EPSPs occurring close together in time from the "same" presynaptic neuron. (2nd one begins before the 1st one ends) |
| spatial summation | ___ ___ is the summation of two or more EPSP's that add to each other (occurred at different locations on the same cell) bringing the postsynaptic membrane to threshold. |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.