CH3: Neurophysiology Flashcards
neurophysiology
the study of the life processes of neurons
ion
an atom or molecule that has acquired an electrical charge by gaining or longs one or more electrons
anion
a negatively charged ion, such as a protein or a chloride
cation
a positively charged ion, such as a potassium or sodium ion
intercellular fluid
the watery solution found within cells
extracellular fluid
the fluid in the spaces between cells
cell membrane
the lipid bilayer that ensheathes a cell
resting potential
the difference in electrical potential across the membrane of a nerve cell at rest
millivolt (mV)
a thousandth of a volt
ion channel
a pore in the cell membrane that permits the passage of certain ions through the membrane when the channels are open
potassium ions (K+)
a potassium atom that carries a positive charge
sodium ions (Na+)
a sodium atom that carries a positive charge
selective permeability
the property of a membrane that allows some substances to pass through, but not others
what are the 2 forces driving the movement of ions into and out of a neuron?
diffusion and electrical pressure
diffusion
the spontaneous spread of molecules from an area of high concentration to an area of low concentration until a uniform concentration is achieved
electrical pressure
the propensity of charged molecules or ions to move toward areas with the opposite charge
what are the functions of the sodium-potassium pump?
the pump is semipermeable and its function is pump 3 sodium (Na+) ions out of the cell for every 2 potassium (K+) ions pumped in. the pump is selectively permeable to K+ but not Na+ ions.
equilibrium potential
the point at which the movement of ions across the cell membrane is balanced, as the electrostatic pressure pulling ions in one direction is offset by the diffusion force pushing them in the opposite direction
axon hillock
the cone-shaped area on the cell body from which the axon originates
hyperpolarization
an increase in membrane potential (the inside of the neuron become even more negative or farther from zero)
depolarization
a decrease in membrane potential (the inside of the neuron becomes less negative or closer to zero)
local potential
an electrical potential that is initiated by stimulation at a specific site, which is a graded response that spreads passively across the cell membrane, decreasing in strength with time and distance