Graded Potentials

graded potentials

changes to the resting membrane potentials (-70) after the establishment of the RMP

AFTER establishment of RMP

when do graded potentials occur

to produce electrical signals in excitable cells

why is it important to experience changes in the membrane potential from resting levels

changes in permeability of the cell membrane to ions

how do changes in membrane potential occur

depolarization

membrane potential becomes less negative (towards 0)

overshoot

membrane potential gets to 0 and then continues to become more positive

repolarization

returning of the membrane potential from a positive value to -70 mV

hyperpolarization

The movement of the membrane potential of a cell away from rest potential in a more negative direction.

thousands

how many synapses occur on one post-synaptic cell

excitatory, inhibitory

each synapse produces a small post-synaptic signal in the form of neurotransmitters which can be _________ or _________, based on the NT and its receptors

graded potentials

signals between pre and postsynaptic neurons utilize

chemically, mechanically, ions

a graded potential occurs when a channel is stimulated _________ or ____________ allowing it to open, the open channel allows for an influx of ____ (either positive or negative) resulting in a change to the membrane potential

NT, ligand, depolarization

an example of how graded potentials occur is when a __ binds to cation ________-gated channel causing a chemical stimulus to open the channel, once open there is an influx of cations which are attracted to the negative charges of the intracellular fluid, the influx of cations causes a _________ of the membrane (more positive)

TRUE
(weaker stimuli = weaker effect)

true or false: graded potentials are proportional to the size of the stimulus

charges leak out thru membrane (mostly K+)

why does the graded potential decrease as the distance from the initial location increases

FALSE (graded potentials can be depolarizations or hyperpolarizations)

true or false: graded potentials can only be depolarizations

excitatory

depolarization results from what type of stimulus

inhibitory

hyperpolarization results from what type of stimulus

combine

summation of graded potentials means that if 2 graded potentials occur close to the same time, their effects may ______

synaptic potentials

between neurons
graded potential change produced in the postsynaptic neuron in response to the release of a neurotransmitter

receptor potential

a graded potential produced at the peripheral endings of afferent neurons in response to a stimulus

pacemaker potential

spontaneous graded potential change that occurs in certain specialized cells (Ex: muscle cells)

dendrites and cell body

Where do graded potentials occur?

post

each synapse produces a small ____-synaptic signal

permeability

changes in membrane potential occur because of changes in the ___________ of the cell membrane to ions

graded potential

the synapse of a presynaptic axon terminal and a post synaptic dendrite or cell body has an electrical signal, that is the ______ ________ via the NTs

short, ionic

graded potentials are ____ distance signals that rely only on local flow of ______ currents

proportional

graded potentials are “graded” or ___________ to the size of the stimulus

weaker

the weaker the stimulus, the _______ the graded potential

decrease

graded potentials ________ with distance from the stimulus site, local current is decremental