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24 terms

Unit 3 A: The Neuron

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biological psychology
a branch of psychology concerned with the links between biology and behavior
neuron
a nerve cell; the basic building block of the nervous system
sensory neurons
type of neuron that carries INCOMING MESSAGES FROM THE SENSORY RECEPTORS (found in the eyes, ears, skin, etc.) to the brain or the spinal cord; known also as afferent neurons
motor neurons
neurons that carry outgoing information from the central nervous system to the muscles and glands; also known as efferent neurons
interneurons
neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs.
dendrite
the bushy, branching extensions of a neuron that RECEIVE messages and conduct impulses toward the cell body
axon
the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands
cell body
the neuron's life-support center; also known as the soma
myelin sheath
a layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next
action potential
a neural impulse; a brief electrical charge that travels down an axon
threshold
the level of stimulation required to trigger a neural impulse
synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
neurotransmitters
chemical messengers that traverse the synaptic gaps between neurons. When released by the sending neuron, they travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.
reuptake
a neurotransmitter's reabsorption by the sending neuron
acetylcholine (Ach)
enables muscle action, learning, and memory; with Alzheimer's disease, the neurons that produce it deteriorate
dopamine
a neurotransmitter associated with movement, attention and learning and the brain's pleasure and reward system; excess activity of this neurotransmitter is linked to schizophrenia, and the lack of it is related to the decreased mobility and tremors of Parkinson's disease
serotonin
a neurotransmitter that affects hunger, sleep, arousal, and mood; it appears in lower than normal levels in depressed persons
norepinephrine
helps control alertness and arousal; an undersupply can depress mood; while an oversupply can lead to mania
GABA (gamma-aminobutyric acid)
a major inhibitory neurotransmitter; an undersupply linked to seizures, tremors, anxiety and insomnia
glutamate
a major excitatory neurotransmitters: involved in memory. Oversupply can overstimulate brain,producing migraines or seizures (which is why some people avoid MSG (monosodium glutamate) in food
endorphins
natural, opiatelike neurotransmitters linked to pain control and to pleasure
agonists
a drug that is similar enough in structure to a neurotransmitter molecule to mimic its effects (e.g., morphine mimics the action of endorphins)
antagonists
a drug that is similar enough in structure to a neurotransmitter to occupy its receptor site and block its action, but not similar enough to stimulate the receptor (e.g., the poison called curare paralyzes its victims by blocking the receptor sites for Ach)
Resting potential
State in which a neuron is NOT transmitting a nerve impulse. A neuron in this state has a net negative charge relative to its outside environment, and this state of potential energy prepares it to be activated by an impulse from an adjacent neuron.