Ch 4 Neural Conduction & Synaptic Transmission Flashcards
Ionotropic Receptors
Receptors that are associated with ligandactivated ion channels.
Norepinephrine
One of the three catecholamine neurotransmitters.
Catecholamines
The three monoamine neurotransmitters that are synthesized from the amino acid tyrosine: dopamine, epinephrine,and norepinephrine.
Opioid Peptides
One of the five classes of neuropeptide transmitters; it consists of those with a structure similar to the active ingredients of opium.
Metabotropic Receptors
Receptors that are associated with signal proteins and G proteins.
Atropine
A receptor blocker that exerts an antagonistic effect at muscarinic receptors.
Nondirected Synapses
Synapses at which the site of neurotransmitter release and the site of neurotransmitter reception are not close together
Anandamide
The first endogenous endocannabinoid to be discovered and characterized.
Excitatory postsynaptic potentials(EPSPs)
Graded post-synaptic depolarizations, which increase the likelihood that an action potential will be generated.
Axon initial segment
The segment of the axon where action potentials are generated—located immediately adjacent to the axon hillock.
Directed Synapses
Synapses at which the site of neurotransmitter release and the site of neurotransmitter reception are in close proximity.
Neuropeptide Transmitters
Peptides that function as neurotransmitters, of which about 100 have been identified; also called neuropeptides.
Spatial Summation
The integration of signals that occur at different sites on the neuron’s membrane.
Soluble-gas neurotransmitters
A class of unconventional neurotransmitters that includes nitric oxide and carbon monoxide.
Transporters
Mechanisms in the membrane of a cell that actively transport ions or molecules across the membrane.
Ligand
A molecule that binds to another molecule; neurotransmitters are ligands of their receptors.
Ions
Positively or negatively charged particles.
Gamma-aminobutyric acid(GABA)
The amino acid neurotransmitter that is synthesized from glutamate; the most prevalent inhibitory neurotransmitter in the mammalian nervous system.
Enzymes
Proteins that stimulate or inhibit biochemical reactions without being affected by them.
Exocytosis
The process of releasing a neurotransmitter.
Sodium−potassium pumps
Active transport mechanisms that pump Na+ ions out of neurons and K+ ions in.
Graded Responses
Responses whose magnitude is indicative of the magnitude of the stimuli that induce them.
Autoreceptors
A type of metabotropic receptor located on the presynaptic membrane and sensitive to a neuron’s own neurotransmitter.
Aspartate
An amino acid neurotransmitter that is a constituent of many of the proteins that we eat.
Reuptake
The drawing back into the terminal button of neurotransmitter molecules after their release into the synapse; the more common of the two mechanisms for deactivating a released neurotransmitter.
Glycine
An amino acid neurotransmitter that is a constituent of many of the proteins that we eat.
Microelectrode
Extremely fine recording electrodes, which are used for intracellular recording.
Amino acid neurotransmitters
A class of small-molecule neurotransmitters, which includes the amino acids glutamate and GABA.
Dendritic Spines
Tiny nodules of various shapes that are located on the surfaces of many dendrites and are the sites of most excitatory synapses in the mature mammalian brain.
All or none responses
Responses that are not graded, that either occur to their full extent or not at all.
Endogenous
Naturally occurring in the body (e.g., endogenous opioids).
Dopamine
One of the three catecholamine neurotransmitters; dopaminergic neurons are damaged in Parkinson’s disease and too much of it in schizophrenia people
Threshold of excitation
The level of depolarization necessary to generate an action potential, usually about -65 mV.
Nitric Oxide
A soluble-gas neurotransmitter.
Monoamine neurotransmitters
Small-molecule neurotransmitters that are synthesized from monoamines and comprise two classes: catecholamines and indolamines.
G Proteins
Proteins that are located inside neurons (and some other cells) and are attached to metabotropic receptors in the cell membrane.
Endorphines
A class of endogenous opioids.
Indolamines
The class of monoamine neurotransmitters that are synthesized from tryptophan; serotonin is the only member of this class found in the mammalian nervous system.
Epinephrine
One of the three catecholamine neurotransmitters.
Miscellaneous peptides
One of the five classes of neuropeptide transmitters; it consists of those that don’t fit into the other four classes.
Membrane Potential
The difference in electrical charge between the inside and the outside of a cell.
Voltage-activated ion channels
Ion channels that open and close in response to changes in the level of the membrane potential.
Orthodromic conduction
Axonal conduction in the normal direction—from the cell body toward the terminal buttons.
Acetylcholine
A neurotransmitter that is created by the addition of an acetyl group to a choline molecule.
Agonists
Drugs that facilitate the effects of a particular neurotransmitter.
Periaqueductal gray (PAG)
The gray matter around the cerebral aqueduct, which contains opiate receptors and activates a descending analgesia circuit.
Antidromic conduction
Axonal conduction opposite to the normal direction; conduction from axon terminals back toward the cell body.
Antagonists
Drugs that inhibit the effects of a particular neurotransmitter.
Brain−gut peptides
One of the five classes of neuropeptide transmitters; consists of those first discovered in the gut.
Receptors
Cells that are specialized to receive chemical, mechanical, or radiant signals from the environment; also proteins that contain binding sites for particular neurotransmitters.
Receptor Subtypes
The different types of receptors to which a particular neurotransmitter can bind.
Integration
Adding or combining a number of individual signals into one overall signal.
Absolute refractory period
A brief period (typically 1 to 2 milliseconds) after the initiation of an action potential during which it is impossible to elicit another action potential in the same neuron.
Coexistence
The presence of more than one neurotransmitter in the same neuron.
Enkephalins
The first class of endogenous opioids to be discovered.
Ion Channels
Pores in neural membranes through which specific ions pass.
Inhibitory postsynaptic potentials(IPSPs)
Graded post-synaptic hyperpolarizations, which decrease the likelihood that an action potential will be generated.
Nodes of Ranvier
The gaps between adjacent myelin segments on anaxon.
Action Potential
A massive momentary reversal of a neuron’s membrane potential from about –70 mV to about +50 mV.
Synaptic vesicles
Small spherical membranes that store neurotransmitter molecules and release them into the synaptic cleft.
Enzymatic Degradation
The breakdown of chemicals by enzymes—one of the two mechanisms for deactivating released neurotransmitters
Hyperpolarize
To increase the resting membrane potential.
Temporal Summation
The integration of neural signals that occur at different times at the same synapse.
Axon Hillock
The conical structure at the junction between the axon and cell body.
Depolarize
To decrease the resting membrane potential.
Pituitary peptides
One of the five classes of neuropeptide transmitters; it consists of those first identified as hormones released by the pituitary.
Acetylcholinesterase
The enzyme that breaks down the neurotransmitter acetylcholine.
Saltatory conduction
Conduction of an action potential from one node of Ranvier to the next along a myelinated axon.
Serotonin
An indolamine neurotransmitter; the only member of this class of monoamine neurotransmitters found in the mammalian nervous system.
Resting Potential
The steady membrane potential of a neuron at rest, usually about -70 mV.
Glutamate
The brain’s most prevalent excitatory neurotransmitter, whose excessive release causes much of the brain damage resulting from cerebral ischemia.
Second messenger
A chemical synthesized in a neuron in response to the binding of a neurotransmitter to a metabotropic receptor in its cell membrane.
Gap Junctions
Narrow spaces between adjacent neurons that are bridged by fine tubular channels containing cytoplasm, through which electrical signals and small molecules can pass readily.
Relative refractory period
A period after the absolute refractory period during which a higher-than-normal amount of stimulation is necessary to make a neuron fire.
Carbon Monoxide
A soluble-gas neurotransmitter.
Receptor Blockers
Antagonistic drugs that bind to postsynaptic receptors without activating them and block the access of the usual neurotransmitter.
Endocannabinoids
A class of unconventional neurotransmitters that are chemically similar to the active components of marijuana.
Hypothalamic peptides
One of the five classes of neuropeptide transmitters; it consists of those first identified as hormones released by the hypothalamus.
Neuropeptides
Short amino acid chains comprising between 3 and 36 amino acids.
Golgi complex
Structures in the cell bodies and terminal buttons of neurons that package neurotransmitters and other molecules in vesicles.
