Unformatted text preview: Neural Neural Communication Basic Terminology – Neuronal Parts Basic Terminology – Neuronal Parts Neuron – basic building block of the nervous Neuron system system Dendrite – part of neuron that receives Dendrite messages from other cells and passes the messages to the cell body messages Cell Body – control center of neuron Axon – sends messages to other neurons, Axon glands, muscles, etc glands, Cont. Cont. Myelin Sheath – fatty tissue covering some Myelin axons, speeds conduction of neural impulse axons, Synapse – Junction between axon of one Synapse neuron and dendrite of another neuron Action potential – brief electrical charge that Action travels down an axon. Caused by positively charged atoms moving in and out of channels on the axon’s membrane. on Threshold – the level of stimulation required Threshold to trigger an action potential. Threshold is reached through depolarization. reached Basic Terminology – Neural Basic Terminology – Neural Communication Cont. Cont. Depolarization – When the inside of an axon Depolarization switches from a negative to positive charge, through an inward flow of ions. through Hyperpolarization – Return of the inside of the Hyperpolarization axon to a negative charge. axon Cont. Cont. All-or-none – Action potentials can’t be All-or-none partial, they either happen or they don’t. partial, Refractory period – the period in which a new Refractory action potential can’t occur Neurotransmitters Neurotransmitters
- Chemical messengers that traverse the Chemical synaptic gaps between neurons. synaptic Dopamine – movement, learning, attention, Dopamine emotion, reward (linked with schizophrenia, Parkinson’s) Parkinson’s) Cont. Cont.
- - Serotonin – mood, hunger, sleep, arousal Serotonin (linked with depression) (linked Norepinephrine – alertness and arousal Endorphins – natural opiate-like transmitters Endorphins linked to pain control and pleasure linked Sequence of Events Sequence of Events
1. 2. 3. 4. Dendrite receives messages in the form of Dendrite neurotransmitters. neurotransmitters. Through temporal and spatial summation, Through message is passed to cell body. message Depolarization of cell body begins. If depolarization is sufficient to reach If threshold, action potential occurs. threshold, Cont. Cont.
1. 2. 3. 4. Action potential travels down axon. At the synapse, action potential is At “converted” to neurotransmitter which is released into synaptic cleft. released NT binds to receptors on dendrites of next NT neuron (Process starts over in new neuron) . neuron Hyperpolarization occurs in original neuron Hyperpolarization and refractory period is entered. and ...
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- Spring '08
- neuron axon, Cont. Cont