Unit 2 Flashcards
Neuron
A nerve cell; a basic building block of the nervous system.
Cell body
Part of a neuron; contains the nucleus.
Dendrites
Neuron’s bushy, branching extensions that receive and integrate messages.
Axon
Neuron extension; passes messages through branches to other neurons/muscles/glands.
Myelin Sheath
The fatty tissue layer encasing axons; enables greater transmission speed (looks like hotdog buns).
Multiple Sclerosis
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Myelin sheath degenerates; communication to muscle slows and eventual loss of muscle control.
Glial Cells
Cells in the nervous system that support, nourish, and protect neurons.
Action potential
A neural impulse; a brief electrical charge travels down an axon.
Threshold
Level of stimulation required to trigger a neural impulse.
Refractory period
A brief resting period that occurs after a neuron has fired (goes down like a chain).
All-Or-None response
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Neuron’s reaction of either firing (with full strength) or not firing.
Synapse
The junction between the axon tip of the sending neuron and the dendrite/cell body of the receiving neuron.
Neurotransmitter
Chemical messengers that cross synaptic gaps between neurons.
Reuptake
Neurotransmitter reabsorption by sending neurons.
Acetylcholine (ACh)
Enables muscle action, learning, and memory (Increased secretions, memory, and muscle contractions. Decreased heart rate).
Dopamine
Influences movement, learning, attention, and emotion (Increased alertness and happiness. Decreased hunger).
Serotonin
Affects mood, hunger, sleep, and arousal (Increased happiness and fullness. Decreased pain).
Norepinephrine
Helps control alertness and arousal (Increased heart rate, alertness, happiness. Decreased blood circulation and pain).
GABA (gamma-aminobutyric acid)
A major inhibitory neurotransmitter (Increased sleepiness. Decreased anxiety, alertness, memory, muscle tension).
Glutamate
A major excitatory neurotransmitter is involved in memory (most common).
Endorphins
Natural opiates - Neurotransmitters that influence the perception of pain and pleasure.
Agonist
A molecule that increases a neurotransmitter’s action
3 ways agonists can work
- Increase neurotransmitter action.
- Increase production/release neurotransmitters, or block reuptake in synapse.
- May be similar enough to neurotransmitters to bind to its receptor and mimic its ex/in effects.
Antagonist
A molecule that inhibits/blocks the action of a neurotransmitter (causes paralysis by blocking ACh release).