PSB-2000 Study Guide - Midterm Guide: Resting Potential, Axon Hillock, Chemical Synapse
Document Summary
Describe the resting membrane potential and its ionic basis: resting membrane potential; difference in electrical charge between inside and outside of cell. Inside of neuron is negative, resting membrane potential is about -70mv. Ionic basis of resting potential: factors contributing to even ion distribution; random motion; particles tend to move down their connection gradient. Electrostatic pressure; like repels like, opposites attract: factors contributing to uneven ion distribution; selective permeability to certain ions, sodium-potassium pumps. Explain postsynaptic potentials: neurotransmitters bind at postsynaptic receptors chemical messengers bind and cause electrical changes = changes in the membrane potential of the postsynaptic terminal of a chemical synapse. Depolarization makes the membrane potential less negative. Hyperpolarization makes the membrane potential more negative. Describe the summation of postsynaptic potentials: o(cid:374)e ep p (cid:449)ill (cid:374)ot (cid:271)e e(cid:374)ough to (cid:272)ause a (cid:862)fire(cid:863) a(cid:374)d release a (cid:374)eurotransmitter summation is needed, to do this, the threshold of activation must be reached near the axon hillock.
