PHYS20009 Lecture Notes - Lecture 14: Alpha Motor Neuron, Resting Potential, Tendon Reflex

• School: University of Melbourne
• Department: Physiology
• Course: PHYS20009
• Professor: Charles

Document Summary

* change in permeability of sodium or potassium ions will change membrane potential e. g. If (cid:449)e a(cid:396)e (cid:373)o(cid:396)e pe(cid:396)(cid:373)ea(cid:271)le to potassiu(cid:373), (cid:449)e sit (cid:272)lose(cid:396) to potassiu(cid:373)"s e(cid:395)uili(cid:271)(cid:396)iu(cid:373) pote(cid:374)tial. * at rest we have more potassium leak channels than sodium leak channels, so we sit closer to potassiu(cid:373)"s e(cid:395)uili(cid:271)(cid:396)iu(cid:373) pote(cid:374)tial, so (cid:396)esti(cid:374)g (cid:373)e(cid:373)(cid:271)(cid:396)a(cid:374)e pote(cid:374)tial = -70mv. * if all sodium leak channels are blocked at rest this means that there is no sodium permeability and hence resting membrane potential would be -90mv (at potassium equilibrium potential) We maintain concentrations through the sodium potassium pump. * the lower/small the concentration gradient, the closer it is to 0mv. * at resting membrane potassium, sodium has a greater drive to enter the cells than potassium has to leave this cell (this is due to the charge difference) * so concentrations of ions and permeability of ions determine the resting membrane potential.