Neurophysiology Flashcards
Main inhibitory neurotransmitter
GABA
Main excitatory neurotransmitter
glutamate
Characteristics of EPSPs and IPSPs
graded and decremental (they vary in size depending on the type of stimulation and they decrease in power the further they get from the source of activation)
How can the electronegativity inside a neuron be explained?
Na+ channels are closed (while Cl- and K+ are opened) and the transporter actively pumps out Na+. With the biggest supply of the positive charge being pumped to the outside of the cell the inside becomes negative while Cl diffuses through the open channels
Describe an electrical gradient
opposite charges attract
Describe a concentration gradient
Diffusion; ions move from an area of high concentration to an area of low concentration
Which part of the process requires ATP?
The transportation (or pumping) of Na+ out of the cell
What can explain the exponential nature of action potentials? Why does the voltage rise so quickly?
APs are triggered by voltage changes that cross the threshold of excitation at the axon. Voltage gated Na+ channels open and the previously pumped out Na+ shoots into the cell (ascension).
How does myelin make Action potentials faster?
Saltatory conduction! Myelin acts as a speed power up on a video game and allows charges to shoot from one Node of Ranvier to the next all the way down the axon
How are inputs from the somatadendritic region calculated to result in action potentials
They’re summed
Define equilibrium potential
The voltage at which the inward and outward forces (of the cell) are balanced. Requires the cell to become 100% permeable to a given ion (only achievable in theory)
What are the resting voltages for K+, Cl- and Na+?
Voltage for action potential?
K+ -90mv
Cl- -86mv
Na+ 67mv
AP 70mv
Capacitance
the amount of electrical charge stored
Resistance
opposition to the flow of an electrical current
Conductance
the flow of an electric current (opposite of resistance)
