Chapter 4

Question 1

Absolutely Refractory

Answer 1

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.

Question 2

Action Potential

Answer 2

A rapid, temporary change in a cell membrane’s electrical potential, allowing the transmission of a signal along a neuron.

Question 3

Back Propagation

Answer 3

The phenomenon where an action potential that has traveled down an axon is reflected back into the dendrites, affecting synaptic strength and plasticity.

Question 4

Concentration Gradient

Answer 4

The difference in the concentration of a substance across a space or a membrane.

Question 5

Depolarization

Answer 5

A decrease in the electrical charge difference across a cell membrane, making the inside of the cell less negative relative to the outside.

Question 6

Diffusion

Answer 6

The passive movement of molecules or ions from an area of higher concentration to an area of lower concentration.

Question 7

Equilibrium (Reversal) Potential

Answer 7

The membrane potential at which there is no net flow of a particular ion in or out of a cell.

Question 8

Excitatory Postsynaptic Potential (EPSP)

Answer 8

A temporary increase in postsynaptic membrane potential, making the neuron more likely to fire an action potential.

Question 9

Graded Potential

Answer 9

A membrane potential change that varies in size, as opposed to being all-or-none, and diminishes with distance.

Question 10

Hyperpolarization

Answer 10

An increase in the electrical charge difference across a cell membrane, making the inside of the cell more negative relative to the outside.

Question 11

Inhibitory Postsynaptic Potential (IPSP)

Answer 11

A temporary decrease in postsynaptic membrane potential, making the neuron less likely to fire an action potential.

Question 12

Initial Segment

Answer 12

The part of the axon closest to the cell body where action potentials are typically initiated.

Question 13

Relatively Refractory

Answer 13

The period following the absolutely refractory period when a neuron can generate another action potential, but only with a stronger-than-normal stimulus.

Question 14

Resting Potential

Answer 14

The electrical charge difference across a cell membrane in its resting state, typically around -70mV in neurons.

Question 15

Saltatory Conduction

Answer 15

The process by which action potentials jump from one node of Ranvier to the next, increasing the speed of signal transmission along myelinated axons.

Question 16

Spatial Summation

Answer 16

The process by which multiple simultaneous inputs from different locations on a neuron combine to influence the overall membrane potential.

Question 17

Stretch-Activated Channel

Answer 17

Ion channels that open in response to mechanical deformation of the cell membrane.

Question 18

Temporal Summation

Answer 18

The process by which multiple inputs to a neuron occurring at different times combine to influence the overall membrane potential.

Question 19

Threshold Potential

Answer 19

The critical level to which a membrane potential must be depolarized to initiate an action potential.

Question 20

Transmitter-Activated Channel

Answer 20

Ion channels that open or close in response to the binding of a neurotransmitter.

Question 21

Electrical Stimulation

Answer 21

The use of electrical current to stimulate nerves or muscles, often used in research and medical treatments.

Question 22

Electroencephalogram (EEG)

Answer 22

A recording of the electrical activity of the brain, typically used to diagnose neurological conditions.

Question 23

Electrographic Seizures

Answer 23

Seizures that are detected by EEG but may or may not be accompanied by observable clinical symptoms.

Question 24

Microelectrode

Answer 24

A very small electrode used to measure or stimulate electrical activity in cells.

Question 25

Oscilloscope

Answer 25

An electronic device used to display and analyze the waveform of electronic signals.

Question 26

Voltmeter

Answer 26

An instrument used to measure electric potential difference between two points in an electric circuit.

Question 27

Autoimmune Disease

Answer 27

A condition in which the immune system mistakenly attacks the body’s own tissues.

Question 28

Multiple Sclerosis (MS)

Answer 28

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.

Question 29

Nernst Equation

Answer 29

A mathematical formula used to calculate the equilibrium potential for a particular ion based on its concentration gradient across a membrane.

Question 30

Voltage Gradient

Answer 30

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.

Question 31

Optogenetics

Answer 31

A technique that uses light to control cells within living tissue, typically neurons that have been genetically modified to express light-sensitive ion channels.

Question 32

Nerve Impulse

Answer 32

The electrical signal transmitted along a neuron, also known as an action potential.

Question 33

Synapse

Answer 33

The junction between two neurons where communication occurs through neurotransmitter release.

Question 34

Terminal Button (End Foot)

Answer 34

The end of an axon where neurotransmitters are released into the synapse.

Question 35

Voltage-Activated Channel

Answer 35

Ion channels that open or close in response to changes in membrane potential.