PSYC1004 Lecture Notes - Lecture 9: Hermann Von Helmholtz, Resting Potential, Membrane Potential

• School: ANU
• Department: Psychology
• Course: PSYC1004
• Professor: Professor Michael Platow

Document Summary

Intracellular fluid/space (cytosol) = inside the neuron: extracellular fluid/space = outside the neuron. Hermann von helmholtz: fou(cid:374)d that the (cid:374)euro(cid:374) has a(cid:374) ele(cid:272)tri(cid:272)al (cid:272)harge a(cid:272)ross the (cid:373)e(cid:373)(cid:271)ra(cid:374)e, i(cid:374)tra(cid:272)ellular spa(cid:272)e is (cid:374)egati(cid:448)el(cid:455) (cid:272)harged (cid:272)o(cid:373)pared to the positi(cid:448)el(cid:455) (cid:272)harged e(cid:454)tra(cid:272)ellular space. The difference between the electrical charge inside and outside of the cell is called the membrane potential. Resting membrane potential: whe(cid:374) the (cid:374)euro(cid:374) is (cid:374)ot tra(cid:374)s(cid:373)itti(cid:374)g a (cid:373)essage, (cid:449)e sa(cid:455) that the (cid:272)ell is at (cid:858)rest(cid:859, the resti(cid:374)g (cid:373)e(cid:373)(cid:271)ra(cid:374)e pote(cid:374)tial is t(cid:455)pi(cid:272)all(cid:455) arou(cid:374)d -70millivolts (mv) Crossing the membrane: terminology: permeable: can diffuse freely across the membrane - water (h2o), oxygen (o2 ) and. Carbon dioxide (co2 : semi-permeable cannot diffuse across as easily, but still possible - includes some ions (molecules that carry electrical charge) eg. , potassium (k+) and chloride (cl- ) Impermeable cannot cross the membrane unless through a channel - includes larger molecules and other ions eg. , sodium (na+) and calcium (ca2+)