BIO 365S Lecture Notes - Lecture 5: Nernst Equation, Skeletal Muscle, Neurohormone
Neurophysiology
Opening/closing: causes electricity and current in brain; too much
current = epilepsy. In muscles, changing membrane potential also
creates current.
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Neuos hae dedites to eeie ifo. Log aos, do’t at
electrical signals to decrease as it transducts so need insulation
(myelinated), reaches nerve endings (touch other neurons or the
skeletal muscle for contractions).
1st signal = neurohormone, 2nd one = neurotransmitter.
Nest euatio: euiliu potetial eated K+ = -90mV, but in
ealit it’s oe -7V eause it’s ot just solel K+ that’s ausig the
potential. The GHK equation will give -70mV.
Cell membrane is most permeable to K+ when cell si resting, because
based on calculation, the resting membrane potential is closest to
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Document Summary
Opening/closing: causes electricity and current in brain; too much current = epilepsy. In muscles, changing membrane potential also creates current. Lo(cid:374)g a(cid:454)o(cid:374)s, do(cid:374)"t (cid:449)a(cid:374)t electrical signals to decrease as it transducts so need insulation (myelinated), reaches nerve endings (touch other neurons or the skeletal muscle for contractions). 1st signal = neurohormone, 2nd one = neurotransmitter. Ne(cid:396)(cid:374)st e(cid:395)uatio(cid:374)(cid:863): e(cid:395)uil(cid:271)(cid:396)iu(cid:373) pote(cid:374)tial (cid:272)(cid:396)eated (cid:271)(cid:455) k+ = -90mv, but in (cid:396)ealit(cid:455) it"s (cid:373)o(cid:396)e -7(cid:1004)(cid:373)v (cid:271)e(cid:272)ause it"s (cid:374)ot just solel(cid:455) k+ that"s (cid:272)ausi(cid:374)g the potential. Cell membrane is most permeable to k+ when cell si resting, because based on calculation, the resting membrane potential is closest to potential created by potassium only (-70 closer to -90 than +60). Neuron is excitable, changes permeability to different kinds of ions so inside becomes +/-. Have big summation of electrical signals together = reads ecg. Changes in membrane potential: resting membrane potential = -70mv, depolarization. Need to t(cid:396)a(cid:374)sfe(cid:396) the sig(cid:374)al that (cid:272)a(cid:374) last fo(cid:396)e(cid:448)e(cid:396) so sig(cid:374)al (cid:272)a(cid:374)"t die.
