3 Synapses/Neural Integration (pt 2)
Objectives
- Neural Integration
- Presynaptic Modulation
- Neurotransmitter: Structure, Synthesis, and Degradation
Interactive Activities
Critical Thinking Questions
Learning Summary
- Neurons communicate with one another at junctions called synapses.
- At a chemical synapse, an action potential triggers the presynaptic neuron to release neurotransmitters.
- Chemical transmission involves release of chemical messengers known as neurotransmitters.
- There is a small gap between the axon terminal of the presynaptic neuron and the membrane of the postsynaptic cell, and this gap is called the synaptic cleft.
- An EPSP is depolarizing: it makes the inside of the cell more positive, bringing the membrane potential closer to its threshold for firing an action potential.
- IPSPs have the opposite effect. That is, they tend to keep the membrane potential of the postsynaptic neuron below threshold for firing an action potential.
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The integration of postsynaptic potentials that occur in different locations—but at about the same time—is known as spatial summation.
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The integration of postsynaptic potentials that occur in the same place—but at slightly different times—is called temporal summation.
- Divergence has several axon collaterals that communicate with several other neurons.
- Convergence receives communication from hundreds or thousands of neurons.
- Temporal summation has only one synapse through time.
- Spatial summation have several synapse at the same time.
- The regulation of communication across another synapse is called presynaptic modulation.
