Neurophysiology: Action Potentials, Ion Channels, Membrane Potential, and Ion Transport, Quizzes of Psychology

Download Neurophysiology: Action Potentials, Ion Channels, Membrane Potential, and Ion Transport and more Quizzes Psychology in PDF only on Docsity! TERM 1 Action Potential DEFINITION 1 a brief fluctuation in membrane potential caused by the rapid opening and closing of voltage-gated ion channels; also known as spike, nerve impulse, or discharge. action potentials sweep like a wave along axons to transfer information from one place to another in the nervous system. TERM 2 Excitable Membrane DEFINITION 2 Any membrane capable of generating action potentials. the membrane of axons and muscle cells is excitable. TERM 3 Resting Membrane Potential DEFINITION 3 the membrane potential, or membrane voltage, maintained by a cell when it is not generating action potentials; also called resting potential. neurons have a resting membrane potential of about -65mV. TERM 4 Ion DEFINITION 4 an atom or molecule that has a net electrical charge because of a difference in the number of electrons and protons. TERM 5 Cation DEFINITION 5 a positively charged ion. TERM 6 Anion DEFINITION 6 a negatively charged ion. TERM 7 Phospholipid Bilayer DEFINITION 7 the arrangement of phospholipid molecules that forms the basic structure of the cell membrane. the core of the bilayer is lipid, creating a barrier to water and to water-soluble ions and molecules. TERM 8 Peptide Bond DEFINITION 8 the covalent bond between the amino group of one amino acid and the carboxyl group of another. TERM 9 Polypeptide DEFINITION 9 a string of amino acids held together by peptide bonds. TERM 10 Ion Channel DEFINITION 10 a membrane-spanning protein that forms a pore that allows the passage of ions from one side of the membrane to the other. TERM 21 Ohm's Law DEFINITION 21 the relationship between electrical current (I), voltage (V), and conductance (g): I = gV. because electrical conductance is the inverse of resistance (R), ohm's law may also be written : V = IR TERM 22 Membrane Potential DEFINITION 22 the voltage across a cell membrane; represented by the symbol Vm. TERM 23 Microelectrode DEFINITION 23 a probe used to measure the electrical activity of cells. microelectrodes have a very fine tip and can be fashioned from etched metal or glass pipettes filled with electrically conductive solutions. TERM 24 Ionic Equilibrium Potential DEFINITION 24 the electrical potential difference that exactly balances an ionic concentration gradient, represented y the symbol Eion; also known as equilibrium potential. TERM 25 Nernst Equation DEFINITION 25 a mathematical relationship used to calculate an ionic equilibrium potential. TERM 26 Sodium-Potassium Pump DEFINITION 26 an ion pump hat removes intracellular Na+ and concentrates intracellular K+, using adenosine triphosphate as its energy source. TERM 27 Calcium Pump DEFINITION 27 an ion pump that removes cytosolic Ca2+. TERM 28 Goldman Equation DEFINITION 28 a mathematical relationship used to predict membrane potential from the concentrations and membrane permeabilities of ions. TERM 29 Depolarization DEFINITION 29 a change in membrane potential, taking it from the value at rest (e.g., -65 mV) to a less negative value (e.g., 0 mV). TERM 30 Blood-Brain Barrier DEFINITION 30 a specialization of the walls of brain capillaries that limits the movement of blood=borne substances into the extracellular fluid of the brain.