BME 603 - Ch. 5

medicineman's version from 2016-02-21 19:57


Question Answer
Synaptic trasnmissionThe process of information transfer at a synapse
Electrical synapsesAllow the direct transfer of ionic current from one cell to the next. Occur at gap junctions. Bidirectional
Gap junctionsSpecial proteins called connexins span gap junctions
ConnexonFormed by six connexin subunits
Gap junction channelsFormed when two connexons (one from each cell) meet and combine
Secretory granules (dense-core vesicles)Larger vesicles in axon terminals. Contain soluble protein
Membrane differentiationsDense accumulations of protein adjacent to and within the membranes on either side of the synaptic cleft
Active zones (membrane differentiation)Site of neurotransmitter release on the presynaptic side
Postsynaptic density (membrane differentiation)Contains the neurotransmitter receptors
Axodendritic synapsesPostsynaptic membrane is on a dendrite
Axosomatic synapsesPostsynaptic membrane is on a cell body
Axoaxonic synapsesPostsynaptic membrane is on another axon
Axospinous synapsesWhen a presynaptic axons contains a postsynaptic dendritic spine
Dendrodendritic synapsesWhen dendrites form synapses with one another
Asymmetrical synapses (Gray's type I synapses)Membrane differentiation on the postsynaptic side is thicker than that on the presynaptic side. Usually excitatory
Symmetrical synapses (Gray's type II synapses)Membrane differentiations are of similar thickness. Usually inhibitory
Neuromuscular junctionOccur between axons and muscle. Always causes an action potential in the muscle. One of the largest synapses in the body and contains many active zones
Motor end plate Postsynaptic membrane of a neuromuscular junction. Contains shallow folds that align with active zones to ensure many neurotransmitters are released onto a large surface
Neurotransmitter categoriesAmino acids (synaptic vesicles), amines (synaptic vesicles), and peptides (synaptic granules)
Amino acidsGlutamate (Glu), gamma-aminobutyric acid (GABA), and glycine (Gly)
AminesAcetylcholine (ACh), dopamine (DA), epinephrine, histamine, norepinephrine (NE), serotonin (5-HT)
PeptidesCholecystokinin (CCK), dynorphin, enkephalins (Enk), N-acetylaspartylglutamate (NAAG), neuropeptide Y, somatostatin, substance P, thyrotropin-releasing hormone, vasoactive intestinal polypeptide (VIP)
TransportersSpecial proteins embedded in the vesicle membrane that concentrate neurotransmitters inside vesicles
Peptides in secretory granules Secretory granules containing the peptide neurotransmitter bud off from the the Golgi apparatus. Granule exocytosis does not occur at the active zone. High-frequency trains of action potentials are required for this so that calcium ion concentrations can build up
Voltage-gated calcium channelsLocated in the axon terminal. Depolarization of the terminal membrane causes them to open in the active zones. This results in an influx of calcium and then neurotransmitters to be released
Transmitter-gated ion channelsReceptors which have a pore that is closed until a specific neurotransmitter binds to it
Excitatory postsynaptic potential (EPSP)A transient postsynaptic membrane depolarization caused by the presynaptic release of neurotransmitter
Inhibitory postsynaptic potential (IPSP) A transient hyperpolarization of the postsynaptic membrane potential caused by presynaptic release of neurotransmitter
G-protein-coupled receptors (metabotropic receptors)Neurotransmitter molecules bind to receptor proteins, the receptor proteins then activate small proteins, called G-proteins, which are free to move along the intracellular face of the postsynaptic membrane, and then the activated G-proteins activate effector proteins. Effector proteins can be G-protein-gated ion channels or they can be enzymes that synthesize second messengers that diffuse away in the cytosol
Second messengers Can activate enzymes that regulate ion channel function and alter cellular metabolism
AutoreceptorsPresynaptic receptors that are sensitive to neurotransmitter released by the presynaptic terminal. Typically G-protein-coupled receptors that stimulate second messenger formation. Commonly inhibit neurotransmitter release or cause synthesis of neurotransmitter
Neuropharmacology The study of the effects of drugs on nervous system tissue
Synaptic integrationThe process by which multiple synaptic potentials combine within one postsynaptic neuron
Miniature PSP (mini)Generated by the transmitter contents of one vesicle
Shunting inhibitionInward movement of negative charges