Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Pema Lama
Nerve Signaling
| Term | Definition |
|---|---|
| Membrane potential | slight excess of positively charged ions on the outside of the membrane and slight deficiency of positively charged ions on the inside of the membrane |
| Polarized membrane | a membrane that exhibits a membrane potential |
| Resting membrane potential (RMP) | Membrane potential maintained by a nonconducting neuron’s plasma membrane; typically 70 mV. The slight excess of positive ions on a membrane’s outer surface is produced by ion transport mechanisms and the membrane’s permeability characteristics |
| Sodium-potassium pump | Active transport mechanism in plasma membrane that transports Na and K in opposite directions and at different rates Maintains an imbalance in the distribution of positive ions, in the inside surface becoming slightly negative with respect to its oute |
| Local potentials | slight shift away from the resting membrane in a specific region of the plasma membrane |
| Excitation | when a stimulus triggers the opening of additional Na channels, allowing the membrane potential to move toward zero (depolarization) |
| Inhibition | when a stimulus triggers the opening of additional K channels, increasing the membrane potential (hyperpolarization) |
| graded potentials | Local potentials are called graded potentials because the magnitude of deviation from the resting membrane potential is proportional to the magnitude of the stimulus |
| Action potential | —the membrane potential of a neuron that is conducting an impulse; also known as a nerve impulse |
| Absolute refractory period | brief period (lasting approximately 0.5 ms) during which a local area of a neuron’s membrane resists restimulation and will not respond to a stimulus, no matter how strong |
| Relative refractory period | time during which the membrane is repolarized and restoring the resting membrane potential; the few milliseconds after the absolute refractory period; will respond only to a very strong stimulus |
| Types of synapses (junctions): Electrical synapses | occur where cells joined by gap junctions allow an action potential to simply continue along postsynaptic membrane |
| Types of synapses (junctions): Chemical synapses | occur where presynaptic cells release chemical transmitters (neurotransmitters) across a tiny gap to the postsynaptic cell, possibly inducing an action potential there |
| Synaptic knob | tiny bulge at the end of a terminal branch of a presynaptic neuron’s axon that contains vesicles housing neurotransmitters |
| Synaptic cleft | space between a synaptic knob and the plasma membrane of a postsynaptic neuron |
| Arrangements of synapses: Axodendritic | axon signals postsynaptic dendrite; common |
| Arrangements of synapses: Axosomatic | axon signals postsynaptic soma; common |
| Arrangements of synapses: Axoaxonic | axon signals postsynaptic axon; may regulate action potential of postsynaptic axon |
| Plasma membrane of a postsynaptic neuron | has protein molecules that serve as receptors for the neurotransmitters |
| Spatial summation | adding together the effects of several knobs being activated simultaneously and stimulating different locations on the postsynaptic membrane, producing an action potential |
| Temporal summation | when synaptic knobs stimulate a postsynaptic neuron in rapid succession, their effects can summate over a brief period to produce an action potential |
| Short-term memories (seconds or minutes) | may result from axoaxonic facilitation or inhibition of the presynaptic axon terminal |
| Intermediate long-term memory (minutes to weeks) | happens when serotonin blocks potassium channels in the presynaptic terminal—thus prolonging the action potential and increasing the amount of neurotransmitter released |
| Long-term memories (months or years) | require structural changes at the synapse—for example, more vesicles, more vesicle release sites, more presynaptic terminals, more sensitive postsynaptic membranes |
| Neurotransmitters | means by which neurons communicate with one another; there are more than 50 compounds known to be neurotransmitters, and dozens of others are suspected |
| Function of a neurotransmitter | is determined by the postsynaptic receptor |
| Two major functional classifications of Neurotransmitters | excitatory neurotransmitters and inhibitory neurotransmitters |
Created by:
Pemalama