UConn PNB 2274 Exam 2 – Tanner Questions and Answers 100% Pass

UConn PNB 2274 Exam 2 – Tanner Questions and Answers 100% Pass Principles Electrostatic Attraction - - charge attraction - positively charged ions will be attracted to negatively charged ions Principles Chemical (diffusional) Gradients - - when a membrane is selectively permeable positively charged ions will flow to the one side making the other side negative due to leak channels. - making one side harder to diffuse with the outside of the cell because it is attracted to the more charged side. Relate diffusional and electrical gradients to behavior of ions - - individually ions will be attracted to one another if opposite charges - A Nernst equilibrium forms when there is a balance of ions between the electrostatic attraction and diffusional gradient of the ions - no ion wants to flow either in or out of the cell. Principles of Equilibrium - membrane potential at which an ion's net flux is 0 2Katelyn Whitman, All Rights Reserved © 2025 Nernst Equation - -used for only one ion at a time -Ex = equilibrium potential -determines the electrical potential (voltage) at which diffusion flow of an ion one way is balanced by electrostatic attraction in the other What effect Equilibrium Potential ( Ex) ? - - temperature - Concentration of ion Mammalian ion concentrations and Nernst Potentials - Ek = -90, ECl = -70, ENa = +60, ECa = +130 - these values can change based on condition Goldman- Hodgkin- Katz Equation - -the membrane is permeable to more than 1 ion at rest -Vm = membrane potential when net flux of all other ions together is 0 -membrane have one Vm value; it is the average Ex values for each ion - ** permeability matters Goldman Equation: Multiple ion Case - Vm is somewhere between the largest Ex and smallest Ex. Goldman Equation: One ion Case - - GHK reduces to Nernst 3Katelyn Whitman, All Rights Reserved © 2025 - Vm approximates Ex of the most permeant ion Depolarization - - Changing membrane potential to be more positive (MORE +) Hyperpolarization - - Changing membrane potential to be more negative (MORE -) Repolarization - Returning membrane potential towards rest potential Dendrite - - input signal -receive incoming signals -passive, graded synaptic potentials Axon - -output signal -an all-or-nothing action potential Action Potentials - - Active - no decrement with distance or tim