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Behavioral Neuro
Ch.2 Communication within neurons
Term | Functions |
---|---|
action potential | series of alterations in the membrane of the axon that permit small charged particles called ions to move between the interior of the axon and the fluid surrounding it. These ion exchanges produce electrical currents. |
membrane potential | any change in charge across the membrane (The forces of diffusion and electrostatic pressure)) |
resting potential | when the membrane stays at about -70m V |
hyperpolarized | when the inside of the axon becomes even more negative relative to the outside |
depolarized | when the inside of the axon becomes more positive |
threshold of excitation | a set point, for depolarization to trigger the main electrical event in an axon |
membrane potential | the electrical charge across a cell membrane, the difference in electrical potential inside and outside the cell |
diffusion | the process by which molecules distribute themselves evenly throughout the medium in which they are dissolved in |
electrical charge | the result of a balance between two opposing forces:diffusion and electrostatic pressure |
electrostatic pressure | The force exerted by the attraction and repulsion of electrolytes- anions(-) and cations(+) |
electrolytes | when some substances are dissolved in water, they split into two parts, each with an apposing electrical charge. |
ions | The charged particles into which electrolytes decompose into. |
A- | organic anions (intracellular fluid only) |
Cl- | chloride ions (predominately extracellular fluid) |
Na+ | sodium ions (predominately extracellular fluid) |
K+ | potassium ions (predominately intracellular fluid) |
sodium-potasium pump | These molecules (ATP)are known as sodium potassium transporters. This continuously pushes Na+ out of the axon. It pushes out 3 Na+ for every 2 K+ in. |
sodium potassium transporters | consists of a large number of protein molecules embedded in the membrane, driven by energy provided by molecules of ATP produced by the mitochondria. |
ion channels | a protein molecule that provides passages "pores" that can open or close to allow ions to enter or leave the cell |
voltage -dependent ion channels | sodium channels that are onlyu opened by changes in the membrane potential |
sodium channel | can permit up to 100 million ions per second when it is open |