Flashcards in Chapter4 Deck (86):
Difference in electrical charge between the inside and the outside of the cell.
Extremely fine recording electrodes, which are used for intracellular recordings.
Resting state of a neuron, about -70mV. Neuron is said to be polarized.
Positively or negatively charged particles.
Specialized pores in the neural membranes that ions pass through. Each one is specialized for the passage of a specific particle.
Active transport mechanisms that pump Na+ ions out of neurons and K+ ions into the neurons.
Mechanisms in the membrane of a cell that actively transport opens or molecules across the membrane.
Decreasing the resting membrane potential of the neuron.....membranes becomes more positive
Increasing the resting membrane potential of the neuron.
Excitatory postsynaptic potentials (EPSPs)
Graded postsynaptic depolarizations, increase the likelihood of generating an action potential.
Inhibitory postsynaptic potentials (IPSPs)
Graded postsynaptic hyperpolarizations, decreases the likelihood of generating an action potential.
Amplitudes are proportional to the intensity of the signals that elicit them. Weak signals elicit small postsynaptic potentials, strong signals elicit large postsynaptic potentials.
Chemicals released from neurons at terminal buttons and interact with specialized receptor molecules on the next neuron- first messengers.
The conical structure at the junction between the cell body and the axon.
Axon initial segment
Where action potentials are generated, adjacent to the axon hillock.
Threshold of excitation
The level of depolarization necessary to elicit an action potential, usually about -65mV.
Massive, momentary reversal of the membrane potential from about -70mV to +50mV.
Responses that are not graded, they either occur to their full extent or do not occur at all.
Adding or combining a number of individual signals into one overall signal.
The integration of signals that occur at different sites on the neuron's membrane.
Postsynaptic potentials produced in rapid succession at the same synapse sum to form a greater signal.
Voltage-activated ion channels
Ion channels that open or close in response to the changes in the level of the membrane potential.
Absolute refractory period
Brief period of about 1 to 2 milliseconds after the initiation of an action potential during which it is impossible to elicit a second one.
Relative refractory period
Period during which it is possible to fire the neuron again but only by applying higher-than-normal levels of stimulation.
If electrical stimulation of sufficient intensity is applied to the terminal end of an axon, and action potential will be generated and will travel along the axon back to the cell body.
Axonal conduction in the natural direction -cell body to terminal ends.
Nodes of ranvier
Gaps between adjacent myelin segments.
Transmission of action potentials in myelinated axons.
Nodes of various shapes that are located on the surface of many dendrites. Where most axodendritic synapses terminate.
Synapse at which the site of neurotransmitter release and the sire of neurotransmitter reception are in close proximity.
Synapses at which the site of release is at some distance from the site of reception.
Short amino acid chains comprising between 3 and 36 amino acids. Large neurotransmitters.
Small spherical membranes that store neurotransmitter molecules and releases them into the synaptic clef.
Packages neurotransmitteres into synaptic vesicles.
Many neurons contain two neurotransmitters. Involves one small-molecule neurotransmitter and a neuropeptide.
Process of neurotransmitter release.
Where neurotransmitters bind in the postsynaptic membrane.
Any molecule that binds to another. Ex: neurotransmitter ___ of its receptor.
The different types of receptors to which a particular neurotransmitter can bind.
Associated with ligandactivated ion channels.
Associated with signal proteins and G proteins.
Guanosine-triphosphate-sensitive proteins. Proteins that are located inside neurons and are attached to metabotropic receptors in the cell membrane.
A chemical synthesized in a neuron in response to the binding of a neurotransmitter to a metabotropic receptor in it's cell membrane.
Metabotropic receptors that have two unconventional characteristics: bind to their neuron's own neurotransmitter molecules and they are located in the presynaptic rather than the post synaptic membrane.
More common of the two deactivating mechanisms. Draw neurotransmitters back into the presynaptic buttons by transporter mechanisms.
A deactivating mechanisms where there is a breakdown of the chemical by enzymes.
Proteins that stimulate or inhibit biochemical reactions without being affected by them.
An enzyme used to breakdown acetylcholine in enzymatic degradation.
Narrow spaces between adjacent cells that are bridged by fine, tubular, cytoplasms-filled proteins called, connexins. They transmit signals more rapidly than chemical synapses.
Synapses of axon terminal buttons on dendrites.
Synapses of axon terminal buttons on somas
Often capable of transmission in either direction.
Mediate presynaptic facilitation and inhibition.
Amino acid neurotransmitters
A class of small-molecule neurotransmitters, which includes the amino acids glutamate and GABA.... usually found in fast acting synapses
The brain's most prevalent excitatory neurotransmitter, whose excessive release cause much of the brain damage resulting from cerebra ischemia.
An amino acid neurotransmitter that is a constituent of many the proteins that we eat.
An amino acid neurotransmitter that is a constituent of the proteins that we eat.
Gamma-aminobutyric acid (GABA)
An amino acid neurotransmitter that is synthesized by a simple modification of the structure of glutamate and is the most prevalent inhibitory neurotransmitter.
Slightly larger than amino acid neurotransmitters with more diffuse effects.
One of the three catecholamine neurotransmitters; dopaminergic neurons are damages in Parkinson's disease.
One of the three catecholamine neurotransmitters.
One of the three catecholamine neurotransmitters.
An indolamine neurotransmitter; the only member of this class of monamine neurotransmitters found in the mammalian nervous system.
The three monoamine neurotransmitters that are synthesizes from the amino acid tyrosine: dopamine, epinephrine, and norepinephrine.
The class of monoamine neurotransmitters that are synthesized from tryptophan; serotonin is the only member of this class found in mammalian nervous system.
A small-molecule neurotransmitter that is at neuromuscular junctions, synapses in the autonomic nervous system, and at synapses at several parts of the central nervous system.
Produced in neural cytoplasm and immediately diffuse through the cell membrane into the extracellular fluid and into nearby cells. Exists for only a few seconds and are soluble in lipids.
A soluble-gas neurotransmitter.
A soluble-gas neurotransmitter.
A class of unconventional neurotransmitters that are similar to THC. They are produced immediately before they are released. They are synthesized in fatty compounds in the cell membrane, are released from dendrites and cell body, and have most the effects on the presynaptic neurons, inhibiting subsequent synaptic transmission.
Most widely studied endocannabinoids.
Large molecule neurotransmitters. Consists of 5 groups: pituitary peptides, hypothalamic peptides, brain-gut peptides, opioid peptides, and miscellaneous peptides.
Contains neuropeptides that were first identified as hormones released by the pituitary.
Contains neuropeptides that were first identified as hormones released by the hypothalamus.
Contains neuropeptides that were first discovered int he gut.
Contains neuropeptides that are similar in structure to the active ingredient in opium.
Catch-all category of neuropeptides that contain all of the neuropeptides that do not fit into one of the other four categories.
Drugs that facilitate the effects of a particular neurotransmitter.
Drugs that inhibit the effects of a particular neurotransmitter.
Antagonistic drug that binds to receptors without activating them, blocking the access of the usual neurotransmitter.
Receptor blocker that exerts it's antagonistic effect by binding to muscarinic receptors. Pupil dilating effect.
Botulinium toxin. A neurotoxin released by a bacterium often found in spoiled food. It is a nicotinic antagonist that blocks the release of acetylcholine at neuromuscular junctions.
Periaqueductal gray (PAG)
The gray matter around the cerebral aqueduct, which contains opiate receptors and activates a descending analgesia circuit. Connects the third and fourth ventricles.
Naturally occurring in the body.
The first class of endogenous opioids to be discovered.