2.02 Flashcards
Diffusion
Process of molecules moving from areas to high concentration to areas of low concentration.
Resting Potential
The state of a neuron when not firing a neural impulse.
Action Potential
The release of the neural impulse, consisting of a reversal of the electrical charge within the axon.
All-or-none principle
The strength by which a neuron responds to a stimulus is independent of the strength of the stimulus. If that stimulus exceeds the threshold potential, the neuron will give a complete response; otherwise, there is no response.
Synaptic vesicles
Saclike structures found inside the synaptic knob containing chemicals.
Neurotransmitters
Chemical found in the synaptic vesicles that, when released, has an effect on the next cell.
Synaptic gap (or synapse)
Microscopic fluid-filled space between the axon terminal of one cell and the dendrites or surface of the next cell. (Neurons never touch)
Receptor sites
Three dimensional proteins on the surface of the dendrites or certain cells of the muscles and glands, which are shaped to fit only certain neurotransmitters.
Excitatory synapses
Synapse at which a neurotransmitter causes the receiving cell to fire.
Inhibitory synapses
Synapse at which a neurotransmitter causes the receiving cell to stop flirting.
Antagonist
Chemical substances that block or reduce a cell’s response to the action of other chemicals or neurotransmitters.
Agonist
Chemical substances that mimic or enhance the effects of neurotransmitter on the receptor sites of the next cell, increasing or decreasing the activity of that cell.
Acetylcholine
Messenger at every junction between motor neuron and muscle. Motor control over large muscle movement. Learning, memory, attention, arousal, emotion, dreaming, sleeping.
Epinephrine
Energy, arousal (adrenaline rush).
Norepinephrine
Eating behavior, learning, and mood. Attention and arousal. Deficiency associated with depression.
Dopamine
Motivation, reward, alertness, learning, emotion. Motor control over voluntary movement. Parkinson’s disease is a result of deterioration of neurons that produce dopamine. Excess receptors for dopamine are found in schizophrenic patients. Studies show that addiction is linked to the dopamine reward centers because certain drugs act as agonists, causing prolonged pleasure.
Serotonin
Mood, emotional states, sleep, temperature regulation, appetite, dreaming, impulsiveness.
GABA
Inhibitor of action potentials. Anxiety and intoxication.
Glutamate
Excitatory, enhances action potentials. Learning, memory, nervous system development, and synaptic plasticity.
Endorphins
Pain reduction, reward and pleasure. Natural opiates that are released in response to pain and exercise (i.e., Runner’s high).
Substance P
Pain perception
Reuptake
Process by which neurotransmitters are taken back into the synaptic vesicles.
Enzygmatic degradation
Process by which the structure of a neurotransmitter is altered so it can no longer act on a receptor.
Selectively Permeable
Permeable to only certain molecules and not to all molecules.
Threshold
The point that must be exceeded to begin producing a given effect or result or to elicit a response.
Refractory period
The amount of time it takes for an excitable membrane to be ready for a second stimulus once it returns to its resting state following excitation.
Presynaptic
Relating to the transmitting end of a discharge across a synapse.
Postsynaptic
Pertaining to or being on the receiving end of a discharge across a synapse.
