Electrical Properties Flashcards
What are the three types of neuronal electrical signals?
receptor potential, synaptic potential, action potential
What are the differences between receptor, synaptic, and action potentials in how they are produced?
receptor is when receptor is stimulated (ie, skin), synaptic is when synapse is stimulated, action is when neuron is stimulate
Order the neuronal electrical signals from fastest to slowest?
action, synaptic, receptor
Membrane potential changes is correlation to what?
current flow (mV)
Does the shape/amplitude of action potentials change when the current is increased?
no the frequency does
What does all or nothing mean in terms of action potentials?
once threshold is passed will produce a unifrom response, if not et than no response
What is a graded potential?
typically produced by sensory neurons or neurotransmitter activity
small change in membrane potential that is proportional to size/intensity of stimulus
Electrochemical equilibrium is the balance between what forces?
chemical driving force (concentration gradient)
electrical driving force (potential difference)
What is the effects of chemica/electrical driving force on the movement of K+?
chemical: conc gradient causes K+ to efflux
electrical: electrical potential diff causes K+ to influx
What is the function of the Nernst equation?
calculating equilibrium potential (voltage where there is no net movement of any ion)
What is the difference between active transporters and ion channels?
active: require energy, create conc. gradients, move ions against gradient
channel: allows ions to diffuse down conc. gradient, only allow certain ions to diffuse
What does the goldman equation calcualte?
considers multiple ions and their permeability, calculates membrane potential
What does the Na+/K+ pump do?
sends 2 K+ into the cell and brings 3 Na+ out of cell (net loss of posititve charge inside the cell)
What does the graph of a receptor potential look like?
big initial spike that drops off and then slowly decreases, fully goes back after stimulation stops
What does the graph of a synaptic potential look like?
big initial spike and then slow decrease
What does hyperpolarization mean?
becoming more negative
What does depolarization mean?
becoming less negative
What happens when you inject a posititve current?
depolarizes (can lead to action potential
After you stop injecting the current what will happen?
the membrane potential will return to normal
What happens over distance to electrical signals?
they decay
Why is Ca2+ a good ion for signalling?
very low concentration inside the cell
Is the concentration of sodium greater inside or outside the cell?
10x greater outisde
Is the concentration of potassium greater inside or outside of the cell?
20x greater inside
What are leaky channels?
some non-gated potassium channels in the membrane allow a slow facilitated diffusion K+ out of the cell, help maintain membrane potential
What does [K]o mean vs [K]e?
potassium conc. outisde vs potassium conc, inside
The inside-negative resting potential arises because?
the membrane of a resting neuron is more permeable to K+ than any other ion, there is more K+ insde than outside
What ion is the membrane of a neuron more permeable to when resting? Why?
K+, more channels are open for potassium when resting
What ion is the membrane more permeable to during an action potential?
Na+, increase in permeability of sodium results in the depolarization part of action potential
What determines the resting potential of giant squid axon?
concentration of potassium
How does a greater conc. of K+ affect the resting membrane potential of squid axon?
increasing the conc. makes the resting potential more positive
