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Sab - Physiology
Physiology Terms etc.
| Question | Answer |
|---|---|
| Conduction with decrement | when graded potentials decrease in strength as they move farther away from the opened ion channel |
| Graded Potential? | When a change in membranes permeability also alters membrane potential and causes an electrical signal |
| Electronic current speed | When a charge spreads along the inside of a membrane |
| Action Potential | -Triggered by the net graded potential at the membrane of the axon hillock -Independent of the stimulus strength -Regenerative |
| Threshold potential | -Membrane potential at which the axon initiates the action potential -Happens at the axon hillock |
| Subthreshold potential | A graded potential that is not large enough to trigger an action potential |
| Suprathreshold potential | A graded potential that is larger than needed to trigger an action potential |
| Excitatory potential | A depolarizing graded potential -brings the membrane potential closer to the threshold potential so that the action potential becomes more likely to happen |
| Inhibitory potential | A hyperpolarizing graded potential -brings the membrane potential farther from the threshold potential, making the action potential less likely to happen |
| Spatial summation | When graded potentials from different sites interact with each other to influence the net change in membrane potential at the axon hillock |
| Where is the axon hillock located on the neuron? | At the junction of the cell body and the axon |
| Synapse | A neuromuscular junction |
| Depolarization | A decrease in the charge difference between the inside and the outside of the cell -positive ions moving into cell -negative ions moving out of cell |
| Hyperpolarization | An increase in the negativity of the membrane potential -negative ions enter cell -positive ions leave cell |
| Repolarization | Cell membrane returns to the resting membrane potential after a depolarization or hyperpolarization event |
| Equilibrium potential | The membrane potential at which the electrical and chemical gradients favoring the movement of a particular ion exactly balance each other out, and there is no net movement of that ion across the membrane |
| Temporal summation | When depolarizations occur at two slightly different times and combine to to determine the net change in membrane potential at the axon hillock |
| Absolute refractory period | Period in which the axon is incapable of generating a new action potential no matter how strong the stimulus |
| Depolarization phase | When the net graded potential at the axon hillock reaches threshold potential |
| Repolarization phase | When the membrane potential rapidly returns to the resting membrane potential after a depolarization event |
| After-hyprepolarization phase | When the membrane potential becomes even more negative than the resting membrane potential, after a repolarization event |
| Relative refractory period | Phase in which a new action potential can be generated but only by very large stimuli |
| Activation gate | Gate that opens a Na+ channel, increasing the permeability of the membrane to Na+ ions. |
| Myelin | Insulating layer covering the axon |
| Schwann cells | Lipid-rich cells that form the myelin sheath by wrapping in a spiral pattern around the axon of the neuron |
| Nodes of Ranvier | Areas of exposed axonal membrane in between myelin sheaths along the axon |
| Internodes | Myelinated regions of the axon |
| Satlatory conduction | -The way neurons conduct signal -Current spreads electronically through internodes, while action potentials occur only in the nodes of Ranvier |
| Pre-synaptic cell | Cell transmitting the signal |
| Postsynaptic cell | Cell receiving the signal |
| Synaptic cleft | Space between the presynaptic and postsynaptic cell |
| Length constant | The distance over which a change in membrane potential will decrease to 37% of its original value |
| Time constant | The time it takes for the membrane potential to decay to 37% of its original value (or reach 63% of its maxinmal value) |
Created by:
admire-brains
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