Chapter 3 terms

Question 1

Neurophysiology

Answer 1

The study of the life processes within the neurons that use electrical and chemical signals.

Question 2

Action Potential

Answer 2

A rapid electrical signal that travels along the axon of a neuron.
Brief but large changes in membrane potential. Produced by the movement of Na+ ions into the cell.

Question 3

Neurotransmitter

Answer 3

A chemical messenger between neurons.

Question 4

Microelectrode

Answer 4

A device inserted into a resting cell to show that it is more negative than the extracellular fluid.

Question 5

Resting membrane potential

Answer 5

-50 to -80 millivolts and shows the negative polarity of the cell’s interior

Question 6

Ion channels

Answer 6

Proteins that span the membrane and allow ions to pass. They open and close in response to voltage changes,chemicals, or mechanical action

Question 7

Selective permeability (in neurons)

Answer 7

In a neuron, the phenomenon that allows K+ ions to enter or leave the cell freely, but restricts the flow of other ions.

Question 8

Diffusion

Answer 8

Force that causes ions to flow from areas of high to low concentration along their concentration gradient.

Question 9

Electrostatic Pressure

Answer 9

Force that causes ions to flow towards oppositely charged areas.

Question 10

Sodium-potassium pump

Answer 10

Neurons use this mechanism to maintain resting potential. It pumps three sodium ions out for every two potassium ions pumped in.

Question 11

Nernst equation

Answer 11

This equation predicts the voltage needed to counterbalance the diffusion force pushing an ion across a membrane.

Question 12

Goldman equation

Answer 12

This equation predicts voltage potentials that are quite close to observed resting potentials. This equation takes into account the intracellular and extracellular concentrations of several ions and the degree of membrane permeability to each

Question 13

Axon Hillock

Answer 13

This is where action potentials originate and are propagated along the axon.

Question 14

Hyperpolarization

Answer 14

An increase in membrane potential- the of the membrane becomes even more negative, relative to the outside.

Question 15

Depolarization

Answer 15

A decrease in membrane potential- the interior of the cell becomes less negative

Question 16

Local potential

Answer 16

An electrical potential that spreads passively across the membrane, diminishing as it moves away from the point of stimulation.

Question 17

Threshold

Answer 17

An action potential is only triggered if it gets to -40mv usually called…

Question 18

After potentials

Answer 18

Changes in membrane potentials after action potentials.

Question 19

Voltage-gated Na+ channels

Answer 19

These channels open in response to the initial depolarization, and allow Na+ ions to enter the cell.

Question 20

Refractory period

Answer 20

Time when only some stimuli can produce an action potential.

Question 21

Absolute refractory phase

Answer 21

Time when no action potentials are produced.

Question 22

Relative refractory phase

Answer 22

Time when only strong stimulation can produce an action potential.

Question 23

Voltage clamping

Answer 23

The use of electrodes to inject current into an axon or neuron to keep the membrane potential at a set value.

Question 24

Patch Clamping

Answer 24

The use of voltage clamping to monitor current flow across a tiny patch of neuronal membrane.

Question 25

Conduction Velocity

Answer 25

The speed of propagation of action potentials-varies with diameter.

Question 26

Postsynaptic potentials

Answer 26

Brief changes in the resting potential of a cell

Question 27

Excitatory postsynaptic potential (EPSP)

Answer 27

Produces a small local depolarization, pushing the cell closer to threshold.

Question 28

Synaptic delay

Answer 28

The delay between an action potential reaching the axon terminal and creating a postsynaptic potential.

Question 29

Inhibitory postsynaptic (IPSPs)

Answer 29

Produces a small hyperpolarization, pushing the cell further away from threshold. It results from chloride ions entering the cell, making the inside more negative.

Question 30

Spatial summation

Answer 30

The summing of potentials that come from different parts of the cell.

Question 31

Temporal Summation

Answer 31

The summing of potentials that arrive at the axon hillock at different times. The closer in time that they arrive, the greater the summation and possibly action potential.

Question 32

Exocytosis

Answer 32

Calcium ions cause synaptic vesicles to fuse with the presynaptic vesicles membrane and release neurotransmitter into the cleft

Question 33

Ligands

Answer 33

Thesee chemicals fit receptors exactly and activate or block them.

Question 34

Endogenous ligands

Answer 34

Neurotransmitters and hormones, ligands produced by the body.

Question 35

Exogenous ligands

Answer 35

Ligands produced outside of the body such as drugs and toxins.

Question 36

Ionotropic receptors (ligand-gated ion channel)

Answer 36

These receptors open when bound by a transmitter.

Question 37

Metabotropic receptors

Answer 37

These receptors recognize the transmitter when it binds and activate G proteins.

Question 38

G proteins

Answer 38

Activated by metabotropic receptors . They open channels or activate another chemical to affect ion channels.

Question 39

Convergence

Answer 39

Many cells send signals to one cell

Question 40

Divergence

Answer 40

One cell sends signals to many cells

Question 41

Tonic-clonic seizure

Answer 41

Abnormal activity throughout the brain.

Question 42

Simple partial seizure

Answer 42

Brain waves show patterns of seizure activity for 5-15 seconds sometimes several times a day. No unusual muscle activity besides stopping and staring. Events during seizure are not remembered.

Question 43

Complex Partial seizures

Answer 43

Seizures that do not involve the entire brain. victims experience Aura.

Question 44

Event-related Potentials (ERPs)

Answer 44

Large potential shifts caused by discrete stimuli