Neurophysiology Flashcards
What ions are concentrated inside a cell at rest?
Potassium and negatively charged proteins
What ions are concentrated outside a cell at rest?
Sodium and Chloride
What is the charge of a cell at rest?
-65 mV
How is membrane potential maintained?
Due to the semipermeable membrane (ions do not cross, channels are mostly closed, and the sodium-potassium pump)
What is the threshold for an action potential to occur?
-40 mV
Describe an Absolute Refractory Period
Sodium channels cannot be opened and an axon membrane cannot trigger a new action potential
Describe a Relative Refractory Period
The axon membrane will only trigger an action potential if the stimulation is higher than the original AP
What factors determine the speed of an action potential?
Diameter (wider=faster) and degree of myelination (more=faster)
What factor(s) of an action potential can change
Rate
What factor(s) of an action potential cannot change?
Speed and size
What would cause an excitatory post-synaptic potential (EPSP) to occur?
Sodium moving across the synapse
What would cause an inhibitory post-synaptic potential (IPSP) to occur
Chlorine moving across the synapse
What is Spatial Summation?
Summation of post-synaptic potentials originating on different parts of the neuron
What is Temporal Summation
Summation of post-synaptic potentials that reach the neuron at different times
