Electrical Signals Are Turned into Chemical Signals at Synapses Flashcards
Exogenous
Arising from outside the body.
Endogenous
Produced inside the body.
Figure 4.1
Synapses convert Electrical Signals into Chemical SIgnals
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Presynaptic
Located on the “transmitting” side of a synapse.
Synapse
The location at which information flows between a presynaptic neuron and a postsynaptic neuron, often through the conversion of electrical activity in the presynaptic neuron into a secretion of chemical neurotransmitter that alters the functioning of the postynaptic neuron.
Exocytosis
A cellular process that results in the release of a substance into the extracellular space.
Neurotransmitter
Also called simply transmitter. A signaling chemical, released by a presynaptic neuron, that diffuses across the synaptic cleft to alter the functioning of the postsynaptic neuron.
Neurotransmitter receptor
Also called simply receptor. A specialized protein that is embedded in the cell membrane, allowing it to selectively sense and react to molecules of the corresponding neurotransmitter.
Postsynaptic
Located on the “recieving” side of a synapse.
Reuptake
The reabsorbtion of moleules of neurotransmitter by the neurons that release them, thereby ending the signaling activity of the transmitter molecules.
Transporter
A specialized membrane component that returns transmitter molecules to the presynaptic neuron for reuse.
Ionotropic receptor
Also called ligand-gated ion channel. A receptor protein containing an ion channel that opens when the receptor is bound by an agonist.
Figure 4.2
The Versatility of Neurotransmitters

Metabotropic receptor
A receptor protein that does not contain ion channels but may, when activated, use a G protein system to open nearby ion channels or to produce other cellular effects.
Amine neurotransmitter
A neurotransmitter based on modifications of a single amino acid nucleus. Examples include acetylcholine, serotonin, and dopamine.
Amino Acid neurotransmitter
A neurotransmitter that is itself an amino acid. Examples include GABA, glycine, and glutamate.
Peptide neurotransmitter
Also called neuropeptide. A neurotransmitter consisting of a short chain of amino acids.
Gas neurotransmitter
A neurotransmitter that is a soluble gas. Examples include nitric oxide and carbon monoxide.
Box: The first transmitter to be discovered was actylcholine

Acetylcholine (ACh)
A neurotransmitter found in the autonomic nervous system, motor systems, and throughout the brain.