action potential Flashcards
what is action potential?
where the neuron is firing and sending a message all the way along an axon, a bigger change
what is resting potential?
when everything is balanced, nothing to react to
what charge does the outside of the cell have?
positive charge
what charge does the inside of the cell have?
negative charge
what charge does potassium have?
positive charge
what charge does sodium have?
positive charge
what is the Threshold?
the minimum amount needed to go into an action potential (-55)
what is a ion channel?
the thing that allows charged particles to go in and out of the cell
nodes of ranvier
interruptions around the axon, during an action potential the current can skip along, a faster process
what makes the inside of the cell negative?
bigger, negatively-charged proteins
what is polarization?
the separation of ions to make the action potential possible
what is the sodium-potassium pump?
takes 2 potassium ions into the cell and 3 sodium ions out of the cell
what is an electrochemical gradient?
when the amount of potassium and sodium have an uneven amount on the inside and outside
what does the ion channel do?
lets ions pass through, depending on their structure and purpose
what is a graded potential?
when only a few ion channels open, and only a bit of sodium enters into the cell, a little change in the membrane potential
gradients
imbalances that create potential energy, all the ions want to leave
Concentration gradients
the attraction to go in or out of the cell because of the charges of the ions (sodium wants to go to the negative)
Electrical gradient
based on the negative charge of the membrane, sodium wants to go in and potassium wants to stay in
what gradients does sodium have at resting potential?
concentration and electrical
what gradients does potassium have at resting potential?
only concentration gradient
depolarization
where neurotransmitters from other neurons will bind to the cell allowing a few sodium ions to enter the cell, therefore reducing the separation of sodium and potassium ions
-makes the inside less negative
Hyperpolarization
when positive ions leave the cell, making the voltage more negative, inhibiting the cell making it less likely to fire an action potential
voltage gated channels
whether they are open or not depends on the charge inside the cell
Absolute refractory period
another action potential is impossible
relative refractory period
the action potential is possible, but requires much more
Propagation
makes it where there are no intermediate of weak action potentials, the exchange of sodium and potassium occurs as the action potential moves down
