Lecture 7 - Synaptic Transmission I. Synapses a....

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Synaptic Transmission I. Synapses a. Features/Functions b. Challenges c. Types II. Electrical Synapses a. Structure i. Presynaptic and post synaptic neurons are linked together by the gap junction. Each contains pores that are closely paired to create a channel much larger than the voltage gated ion channels, allowing substances to diffuse between the membranes. ii. Connexons are the protein subunits that make up these pores. b. Function i. Ionic current flows passively (Direct charge transfer) from one neuron to another. The source of the current is the potential difference locally, created by the AP. The transmission is bidirectional, depending on which neuron has the AP. ii. The current transmitted between the neurons is almost instantaneous thus communication can occur without delay. III. Chemical Synapses a. Overview i. Chemical synapses have a substantially greater gap between them called the synaptic cleft. ii. When an AP reaches the synapse of a presynaptic neuron, the change in membrane potential causes the voltage gated ion channels to open. Because there is a greater concentration of Ca outside than inside, once the channels open, the Ca rushes into the
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This note was uploaded on 02/07/2009 for the course BIPN BIPN 140 taught by Professor Spitzer during the Fall '07 term at UCSD.

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Lecture 7 - Synaptic Transmission I. Synapses a....

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