Term
|
Definition
| The summation of postsynaptic potentials that reach the axon hillock at different times. The closer in time that the potentials occur, the more complete the summation. Compare spatial summation. |
|
|
Term
|
Definition
| Also known as chemically gated ion channel. An ion channel that opens or closes in response to the presence of a particular chemical; |
|
|
Term
|
Definition
| A receptor protein that does not contain an ion channel but may, when activated, use a G protein system to open a nearby ion channel |
|
|
Term
|
Definition
| The form of conduction that is characteristic of myelinated axons, in which the action potential jumps from one node of Ranvier to the next. |
|
|
Term
| resting membrane potential |
|
Definition
| A difference in electrical potential across the membrane of a nerve cell during an inactive period |
|
|
Term
|
Definition
| An equation predicting the voltage needed to just counterbalance the diffusion force pushing an ion across a semipermeable membrane from the side with a high concentration to the side with a low concentration. |
|
|
Term
|
Definition
| An increase in membrane potential (the interior of the neuron becomes even more negative) |
|
|
Term
|
Definition
| A variant of the stretch reflex in which stretching of the tendon beneath the knee leads to an upward kick of the leg |
|
|
Term
|
Definition
| The fact that the amplitude of the action potential is independent of the magnitude of the stimulus |
|
|
Term
|
Definition
| Variation of the concentration of a substance within a region. Molecules and ions tend to move down the concentration gradient from areas of high concentration to areas of low concentration. |
|
|
Term
| excitatory postsynaptic potential |
|
Definition
| A depolarizing potential in the postsynaptic neuron that is caused by excitatory connections. EPSPs increase the probability that the postsynaptic neuron will fire an action potential. |
|
|
Term
| inhibitory postsynaptic potential |
|
Definition
| A hyperpolarizing potential in the postsynaptic neuron that is caused by inhibitory connections. IPSPs decrease the probability that the postsynaptic neuron will fire an action potential |
|
|
Term
|
Definition
| The summation at the axon hillock of postsynaptic potentials from across the cell body. If this summation reaches threshold, an action potential is triggered |
|
|
Term
|
Definition
| A receptor protein that includes an ion channel that is opened when the receptor is bound by an agonist. |
|
|
Term
|
Definition
| A slow-acting substance in the postsynaptic cell that amplifies the effects of synaptic activity and signals synaptic activity within the postsynaptic cell. |
|
|
Term
|
Definition
| A gap between successive segments of the myelin sheath where the axon membrane is exposed |
|
|
Term
|
Definition
| A local potential that is initiated by stimulation at a synapse, can vary in amplitude, and spreads passively across the cell membrane, decreasing in strength with time and distance |
|
|
Term
|
Definition
| In chemistry, the point at which all ongoing reactions are canceled or balanced by others, resulting in a stable, offset, or unchanging system. |
|
|
Term
|
Definition
| A reduction in membrane potential (the interior of the neuron becomes less negative). |
|
|
Term
|
Definition
| The property of a membrane that allows some substances to pass through, but not others. |
|
|
Term
|
Definition
| Transiently inactivated or exhausted. |
|
|
Term
|
Definition
| The spontaneous spread of molecules of one substance among molecules of another substance until a uniform concentration is achieved |
|
|
Term
|
Definition
| The structure of the neuronal cell membrane, which consists of two layers of lipid molecules, within which float various specialized proteins, such as receptors |
|
|
Term
|
Definition
| Also called nerve impulse. The propagated electrical message of a neuron that travels along the axon to the presynaptic axon terminals |
|
|
