PSYCH 330 1st Edition Exam #2 Study GuideLecture #3(February 13th)Discussion of the membrane and the different pathways ions travel through that in turn affect the neuron’s action potential. What are the mechanics of this communication between cells?Electrical Signaling in the membrane:electrical signal that flows through membrane-action potential every cell has a resting potential of 70 mvchanges in action potentiala change in action potential to 50 causes an action potential to pass through the axon and signal a neurotransmitter(a chemical signal) to be releasedall or nothing if cell doesn’t reach threshold then it doesn’t firecells get closer to action potential by depolarization which moves the membrane potential closer to zero, excites itK+ have a higher concentration inside the membrane but A, big proteins, make the resting potential negativehigher concentrations of NA+, Cl outside, positively charged outside a synapse is where this neurotransmitter is receivedchemical signal received by dendrite>electrical signal passes through cell>chemical signal to next cellThe Membranemade of bilipids with proteins embeddedintercellularinside the cell, intracellular outside the membranemembrane is semipermeable because of channels made of proteins that allow electrons to passThese channel proteins are important for the resting potential of the cells: ion channelspassive, use diffusion(high>low), potassiumgated channelsdriven by the concentration gradient if the gate isopened, when a neurotransmitter binds to the gate they openpumps take ATP to transport substances against the concentration gradient, resets the cell by rearranging sodium/potassium concentrations to get back to its resting potentialLecture#4(February 17th)How does depolarization and polarization influence the action potential of the cell? How does the message travel through the cell?Action Potentialmembrane potentialcharge difference across membrane, more positive outside, more negative insidedepolarizationEPSPwhen cell is excited, makes the cell more positive, moves membrane potential toward zero, ex. letting NA+ insidepolarizationIPSPinhibitory, hyperpolarizes, pushes membrane potential farther from zero, further away from being excited, ex. when Cl channel opens and Cl moves into the cell or if the potassium channel opens letting K+ out of the cell> both making the membrane more negative Action potential is EPSP with a threshold of 50 mvrepolarization=getting the cell ready to fire again=1. potassium leaving the cell 2. refractory period= hyperpolarizes and goes below zero resting state, cannot bestimulated 3. pumps out Na+, brings in K+ to return to resting potential, axon is ready to fireagain Physical factors that take part in communicationsummation=how close the synapses are(spatial) and how synchronized the stimulations are(temporal)axon hillockjunction of body to axon, if summed EPSP equals 50 mv at axon hillock, axon will fire/initiate action potentialaction potential flows, with sodium channels regenerating the action potential within the nodes of Ranvier, strictly node to node