Communications at synapses

Communications at synapses - potassium ions will not be...

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AP Biology Communications at Synapses - Synapses = a little tiny gap where neurons use to communicate with one another - Two Types of Synapses: Electrical Synapses and Chemical Synapses a) Electrical Synapses = electrical current between cells by a type of gap junction - Very significant for rapid response (i.e brain activities) b) Chemical Synapses = communicated by neurotransmitters between presynaptic cells and postsynaptic cells 1) Depolarization (Action Potential) opens the calcium ion channels 2) High concentration of calcium ions will for synaptic vesicles 3) Neurotransmitters will be released into the synaptic cleft by exocytosis 4) These neurotransmitters will determine whether the sodium or potassium ions move in or out 5) If neurotransmitters bind to the ion-gated channels, then sodium and potassium ions will in and out: Action potential (depolarization) will be formed and it will be propagated through the axon 6) If neurotransmitters are released from the ion-gated channels, the sodium and
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Unformatted text preview: potassium ions will not be transported-Generation of Postsynaptic Potentials a) Neurotransmitters affect postsynaptic cells by 1) Affecting ion-channel proteins 2) Altering the permeability of cells 3) Causing molecular changes in the cells 4) Initiating signal transduction pathway in the cells b) At the postsynaptic cell, there are two different types of potentials 1) Excitatory Postsynatpic Potentials (EPSPs) Makes the membrane potential positive so that it can reach to the threshold and makes positive Permeable for potassium and calcium ions 2) Inhibitory Postsynatpic Potentials (IPSPs) Makes the membrane potential negative so that it can go back to the refractory period and makes inside Permeable for chloride and sodium ions -Why is the signaling in neurons only one certain direction? a) The generation of electrical signal from axon hillock b) The activation of sodium channels right after inactivation of potassium channels...
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This note was uploaded on 02/11/2012 for the course ZOOLOGY 152 taught by Professor Stephengammie during the Fall '11 term at University of Wisconsin.

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