Module 1.3a Flashcards
(31 cards)
Neuron
A nerve cell; the basic building block of the nervous system
Cell Body
The part of a neuron that contains the nucleus; the cell’s life-support center
Dendrites
A neuron’s often bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body
Axon
The segmented neuron extension that passes messages through it’s branches to other neurons or to muscles or glands
Myelin Sheath
A fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop 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
Refractory Period
In neural processing, a brief resting pause occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting place
All or None Response
A neuron’s reaction of either firing (with all strength) or not. all or nothing. Go big or go home.
Synapse
The junction between the axon tip of the sending neuron & the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft.
Neurotransmitters
Chemical messangers cross the synaptic gap between neurons. When released by the sending neuron, neurotransmitters travel across the synapse & 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
Endorphins
“morphine within” is; natural, opioid-like neurotransmitter linked to pain control and to pleasure. “Feels so good it hurts”
Agonist
A molecule that increases a neurotransmitter’s action
Antagonist
A molecule that inhibits or blocks a neurotransmitter’s action Neurotransmitter = protagonist Molecule = Antagonist
Endocrine System
The body’s “slow” chemical communication system; a set of glands & fat tissue that secrete hormones into the bloodstream
Hormones
Chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream & affect other tissues
Reuptake Inhibitor
Are antidepressants that relieve depression by partially blocking the reuptake of the neurotransmitter serotonin
Acetylcholine (ACh)
Enables muscle action, learning, and memory Ex) with Alzheimer’s disease, Ash-producing neurons deteriorate
Dopamine
Influences movement, learning, attention, & emotion. Ex) Oversupply linked to Schizophrenia. Undersupply linked to tremors & decreased mobility in Parkinsons’ disease
Serotonin
Affects mood, hunger, sleep, & arousal. Ex) undersupply linked to depression. Some drugs that raise serotonin levels are used to treat depression
Norepinephrine
Helps control alertness & arousal. Ex) Undersupply can depress mood. Epinephrine = adrenaline Norepinephrine = counterpart
Gamma-aminobutyric acid (GABA)
A major inhibitory neurotransmitter Ex) Undersupply linked to seizures, tremors, and insomnia
Glutamate
A major excitatory neurotransmitter; involved in memory Ex) Oversupply can overstimulate the brain, producing migraines or seizures
