Lecture 2 Flashcards
speed of communication in an action potential?
the speed of communication is far greater than communication through diffusion or convection. The communication is based upon the membrane
when maintaining the ion concentration gradients across the membrane requires ________.
energy.
the energy required for maintaining the concentration gradients acoss the membrane are provided by?
a chemical process that transforms ATP (stored in the mitochondria) into ADP.
the energy that is provided by a chemical process that transforms ATP into ADP; this mechanism is called _________.
the sodium-potassium pump
what are the 3 ions that play an active role in the electric capabilities of the action potential and are important components influencing neural communication.
K+, Na+, Cl-
the ________ in the concentration of three important ions across the membrane are important
differences
electric potential may emerge ________.
by itself.
what happens when diffusion of ions (Na+ and Cl-) occur at different speeds?
A new state is reached with different ion concentrations to the riht and to the left, the electric force will act in addition to the gradient force.
the membrane may be considered a ______.
capacitor.
why can the membrane be considered a capacitor?
the charge is proportional to the difference of potentials across the membrane, with a coefficient termed capacitance.
the action potential is the dispersion of ___________.
an electric signal.
the _____ of the stimulus dictates the response.
intensity.
small stimulus=small response
medium stimulus=medium response
large stimulus=large response
all or none law
either the membrane does not generate an action potential or it generates an action potential with a standard shape and magnitude
effects of electrical stimulation of a membrane.
if you stimulate a membrane with relatively small electrical stimuli, its resting potential will change somewhat in response to each stimulus and then return to resting level.
refractory period
after an action potential has been generated there is a period of reduced or no possibility of generating another action potential.
relative refractory period
the period following the generation of an action potential in which it is possible to generate another action potential. The second action potential may not be generated with the same intensity of stimulus. An increase in intensity is necessary to generate a new action potential.
absolute refractory period
the period following the generation of an action potential in which it is NOT possible to generate a new action potential.
Positive Feedback
rapid amplification of the effect
Negative Feedback
quickly restores to the original state
Importance of an Action Potential?
the action potential allows for the communication of information at a much more RAPID pace than convection or diffusion
