BIO304H5 Lecture Notes - Lecture 3: Squid Giant Axon, Electrophysiology, Neuroglia
Document Summary
If 10 neurons are firing you look at the sum total. Classical is more interference as it is manually manipulated. [k+] out v/s [k+] in sets the rmp. Introduction to squid giant axon preparation: resting membrane potential. There are three types of potentials" to consider: Membrane voltage when the neuron/cell is at rest. Action and graded potentials are fluctuations from rmp caused by the opening of ion channels. Excitation equates to transient depolarization from rmp. Inhibition equates to transient hyperpolarization from rmp. Neurons muscles and glial cells have different rmps. Rmp represents a difference in charge across the cell membranes. If no movement of charges perfect insulator. Later : ion pumps and exchangers establish the necessary ion concentration gradients. Shuffle ions across the membrane against their gradient. Directly use energy to do this (mostly atp) Because moving ions against their concentration gradient. Use energy from already-established ion concentration gradients (e. g. na + ) to shuffle other molecules/ions across the membrane.
