Chapter 4 Flashcards
Absolutely Refractory
The period during and immediately after an action potential when a neuron cannot generate another action potential, regardless of the strength of the stimulus.
Example sentence: The neuron is in its absolutely refractory period and cannot fire another action potential.
Action Potential
A rapid, temporary change in a cell membrane’s electrical potential, allowing the transmission of a signal along a neuron.
Back Propagation
The phenomenon where an action potential that has traveled down an axon is reflected back into the dendrites, affecting synaptic strength and plasticity.
Concentration Gradient
The difference in the concentration of a substance across a space or a membrane.
Depolarization
A decrease in the electrical charge difference across a cell membrane, making the inside of the cell less negative relative to the outside.
Diffusion
The passive movement of molecules or ions from an area of higher concentration to an area of lower concentration.
Equilibrium (Reversal) Potential
The membrane potential at which there is no net flow of a particular ion in or out of a cell.
Excitatory Postsynaptic Potential (EPSP)
A temporary increase in postsynaptic membrane potential, making the neuron more likely to fire an action potential.
Graded Potential
A membrane potential change that varies in size, as opposed to being all-or-none, and diminishes with distance.
Hyperpolarization
An increase in the electrical charge difference across a cell membrane, making the inside of the cell more negative relative to the outside.
Inhibitory Postsynaptic Potential (IPSP)
A temporary decrease in postsynaptic membrane potential, making the neuron less likely to fire an action potential.
Initial Segment
The part of the axon closest to the cell body where action potentials are typically initiated.
Relatively Refractory
The period following the absolutely refractory period when a neuron can generate another action potential, but only with a stronger-than-normal stimulus.
Resting Potential
The electrical charge difference across a cell membrane in its resting state, typically around -70mV in neurons.
Saltatory Conduction
The process by which action potentials jump from one node of Ranvier to the next, increasing the speed of signal transmission along myelinated axons.
Spatial Summation
The process by which multiple simultaneous inputs from different locations on a neuron combine to influence the overall membrane potential.
Stretch-Activated Channel
Ion channels that open in response to mechanical deformation of the cell membrane.
Temporal Summation
The process by which multiple inputs to a neuron occurring at different times combine to influence the overall membrane potential.
Threshold Potential
The critical level to which a membrane potential must be depolarized to initiate an action potential.
Transmitter-Activated Channel
Ion channels that open or close in response to the binding of a neurotransmitter.
Electrical Stimulation
The use of electrical current to stimulate nerves or muscles, often used in research and medical treatments.
Electroencephalogram (EEG)
A recording of the electrical activity of the brain, typically used to diagnose neurological conditions.
Electrographic Seizures
Seizures that are detected by EEG but may or may not be accompanied by observable clinical symptoms.
Microelectrode
A very small electrode used to measure or stimulate electrical activity in cells.
Oscilloscope
An electronic device used to display and analyze the waveform of electronic signals.
Voltmeter
An instrument used to measure electric potential difference between two points in an electric circuit.
Autoimmune Disease
A condition in which the immune system mistakenly attacks the body’s own tissues.
Multiple Sclerosis (MS)
A chronic autoimmune disease that damages the myelin sheath of nerve cells in the brain and spinal cord, leading to impaired communication between the brain and the rest of the body.
Nernst Equation
A mathematical formula used to calculate the equilibrium potential for a particular ion based on its concentration gradient across a membrane.
Voltage Gradient
The difference in electric potential across a distance, driving the movement of ions.Node of Ranvier: Gaps in the myelin sheath of a neuron where action potentials are regenerated.
Optogenetics
A technique that uses light to control cells within living tissue, typically neurons that have been genetically modified to express light-sensitive ion channels.
Nerve Impulse
The electrical signal transmitted along a neuron, also known as an action potential.
Synapse
The junction between two neurons where communication occurs through neurotransmitter release.
Terminal Button (End Foot)
The end of an axon where neurotransmitters are released into the synapse.
Voltage-Activated Channel
Ion channels that open or close in response to changes in membrane potential.
