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Terms in this set (11)
A space between neurons that are close enough to send a chemical signal.
Presynaptic Neuron Axon Terminal
Postsynaptic Neuron Dendrite
1. Action Potential travels down axon
2. Change in Membrane Potential causes neurotransmitters to be released into the synapse
Neurotransmitters are chemical messengers that diffuse across the synapse to excite or inhibit a neuron or effector. (Acetylcholine is an excitatory neurotransmitter that assists with movement, memory, learning and attention)
3. The neurotransmitters diffuse across the synaptic cleft
4. The neurotransmitter bonds with a receptor on the postsynaptic neuron. If the transmitter is excitatory, channel protein will open and allow Na+ ions into the neuron. If enough neurotransmitters bond to allow enough change in membrane potential, an action potential is sent. If it is inhibitory, channel proteins will allow Cl- ions in or K+ ions out and further hyperpolarize the neuron, making it difficult to send an impulse
5. Enzymes such as cholinesterase will break down the neurotransmitter (acetylcholine) in the synapse and receptors so that the neuron's gates close and allow the neuron to depolarize and send another signal. This rapid cleanup allows for 1000 impulses a second to be sent. Neurotransmitters are broken down (acetate and choline) and are reabsorbed and resynthesized in the presynaptic neuron.
Action Potential is sent
Individually, a neuron cannot depolarize the next one. However, if two neurons fire at the same time and their COMBINED impulses are above the threshold level, the neuron can fire. Produced by the accumulation of neurotransmitters. An excitatory neurotransmitter firing at the same time as an inhibitory neurotransmitter will likely inhibit the impules