BCS 110 Lecture Notes - Lecture 6: Potassium Channel, Axon Hillock, Epsp Synthase
29 Oct 2018
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At rest, the cell membrane is most permeable to k+ because more k+ channels. At rest (at -70mv), k+ leaks out (because its at -100mv = i want to leave, too many potassium). Na+ leaks in (because it"s at +40mv) and cl- is at equilibrium. Sodium-potassium pumps transport 2 k+ in for every 3na+ they transport out to maintain the respective concentration gradients. Depolarization, sodium is free to come in = excitatory postsynaptic potentials; making inside more positive ( epsps make the membrane potential more positive ) Hyperpolarizations, letting potassium flow - making inside more negative, = inhibitory postsynaptic potentials, ipsps make the membrane potential more negative. Graded: amplitude proportional to intensity of stimulus. Rapid: epsps and ipsps travel quickly from receptor to the soma. Dendrites are leaky hoses (receptor at high level, soma much lower level because dendrites are leaky hoses) Decremental: they get smaller as they travel towards the soma.
