Chapter 2 Flashcards
Define resting membrane potential
A negative potential, indicating that neurons have a means of generating a constant voltage across their membranes when at rest
What are Receptor potentials
Receptor potentials are due to the activation of sensory neurons by external stimuli. Graded potentials.
Action Potential
Generate a special type of electrical signal that travels along their long axons. Rapid change in voltage
Synaptic potentials
Allow transmission of information from one neuron to another. Signal neuron recieves
Hyperpolarization
Current makes the membrane potential more negative than resting. (passive electrical responses: doesn’t require the neuron to do anything)
Depolarization
Membrane potential of the nerve cell becomes more positive than the resting potential
Threshold potential
Level of membrane potential at which action potentials are triggered.
Active transporters
Actively move ions into or out of cells against their concentration gradients
Ion channels
Proteins that allow only certain kinds of ions to cross the membrane in the direction of their concentration gradients
Electrochemical equilibrium
An exact balance between two opposing forces:
Amount of particles:
The concentration gradient that causes K+ to move from inside to outside, taking along positive charge
Neurons Charge:
an opposing electrical gradient that increasingly tends to stop K+ from moving across the membrane
Equilibrium potential
The electrical potential generated across the membrane at electrochemical equilibrium
Nernst equation
Ex = 62/z(charge) x log(Outside conc./Inside conc.)
Rising phase
The membrane becomes extraordinarily permeable to Na+
Falling phase
Voltage gated Na+ channels inactivate. K+ exits the neuron
Overshoot
Action potential at its peak, most +
Undershoot
Hyperpolarization, more negative than resting after an AP for a short period as voltage gated Na channels reactivate.
