neuron-->substance-p

Module 1.3a

•Neurons – Nerve cells; the basic building blocks of the nervous system.

•Cell body (soma) – The neuron’s life-support center that processes information. (nucleus)

•Dendrites – Branchlike fibers that receive messages from sensory receptors or other neurons and conduct impulses toward the cell body.

•Axon hillock – Region where the neuron integrates signals and may trigger an action potential.

•Axon – Long fiber that transmits electrical impulses away from the cell body.

•Myelin sheath – Fatty tissue that insulates axons and speeds neural impulses. Multiple sclerosis

•Nodes of Ranvier – Gaps in the myelin sheath that help speed up signal transmission.

•Terminal buttons – Small structures at axon ends that release neurotransmitters.

•Glial cells – Support, nourish, and protect neurons; play a role in learning and memory.

•Resting potential – The neuron’s stable, negative charge when not firing.

•Threshold – The level of stimulation required to trigger a neural impulse.

•Action potential (nerve impulse) – A brief electrical charge that travels down the axon.

•All-or-none response – A neuron fires completely or not at all.

•Refractory period – A brief resting phase after a neuron fires when it cannot fire again.

•Synapse – The gap between neurons where neurotransmitters are released.

•Reuptake – The reabsorption of neurotransmitters by the sending neuron.

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Neurotransmitters - chemical messengers that cros the synaptic gaps between neruons; 60 of them.

•Acetylcholine (ACh) – Enables muscle action, learning, and memory. Too much is movement without control : convulsions. Too little : alzheimers

•Dopamine – Influences movement, learning, attention, and emotion. Deals with fluidity of movement. Too much: delusions, hallucinations, found in people with schizophrenia,

Too little: parkinsons

•Serotonin – Affects mood, hunger, sleep, and arousal. Also deals with impulsive or aggresive behavior. Too much: addiction; Too little: depression

•Norepinephrine – Helps control alertness and arousal. Too much: schizophrenia Too little: depression

•GABA – Major inhibitory neurotransmitter, calming neural activity. Too much: sedation; Too little: seizures, tremors, insomnia, anxiety disorders

•Glutamate – Major excitatory neurotransmitter, involved in memory. Too much: overstimulation, migraine, and seizures Too little: no energy to do anything

•Endorphins – Natural opiates that reduce pain and boost pleasure. Too much: euphoria/dependence; Too little: stress or pain

•Substance P – Neurotransmitter involved in pain perception. Too much: chronic pain;