Neurons

Question 1

A transient all-or-nothing electrical current that is conducted down the axon when the
membrane potential reaches the threshold of excitation.

Answer 1

Action potential

Question 2

Part of the neuron that extends off the soma, splitting several times to connect with other
neurons; main output of the neuron.

Answer 2

Axon

Question 3

The force on two ions with similar charge to repel each other; the force of two ions with
opposite charge to attract to one another.

Answer 3

Electrostatic pressure

Question 3

A bi-lipid layer of molecules that separates the cell from the surrounding extracellular fluid.

Answer 3

Cell membrane

Question 4

Part of a neuron that extends away from the cell body and is the main input to the neuron.

Answer 4

Dendrite

Question 5

A depolarizing postsynaptic current that causes the membrane potential to become more
positive and move towards the threshold of excitation.

Answer 5

Excitatory postsynaptic potentials

Question 6

The force on molecules to move from areas of high concentration to areas of low
concentration.

Answer 6

Diffusion

Question 7

A hyperpolarizing postsynaptic current that causes the membrane potential to become more
negative and move away from the threshold of excitation.

Answer 7

Inhibitory postsynaptic potentials

Question 7

Ion channel that opens to allow ions to permeate the cell membrane under specific conditions such as the presence of a neurotransmitter or a specific membrane potential.

Answer 7

Ionotropic receptor

Question 8

Substance around the axon of a neuron that serves as insulation to allow the action potential
to conduct rapidly toward the terminal buttons.

Answer 8

Myelin sheath

Question 8

Proteins that span the cell membrane, forming channels that specific ions can flow through
between the intracellular and extracellular space.

Answer 8

Ion channels

Question 9

Chemical substance released by the presynaptic terminal button that acts on the postsynaptic
cell.

Answer 9

Neurotransmitters

Question 10

Collection of nerve cells found in the brain which typically serve a specific function.

Answer 10

Nucleus

Question 11

The voltage inside the cell relative to the voltage outside the cell while the cell is a rest
(approximately -70 mV).

Answer 11

Resting membrane potential

Question 12

An ion channel that uses the neuron’s energy (adenosine triphosphate, ATP) to pump three
Na+ ions outside the cell in exchange for bringing two K+ ions inside the cell.

Answer 12

Sodium potassium pump

Question 13

Cell body of a neuron that contains the nucleus and genetic information, and directs protein
synthesis.

Answer 13

Soma

Question 14

Protrusions on the dendrite of a neuron that form synapses with terminal buttons of the
presynaptic axon.

Answer 14

Spines

Question 15

Junction between the presynaptic terminal button of one neuron and the dendrite, axon, or
soma of another postsynaptic neuron.

Answer 15

Synapse

Question 16

Also known as the synaptic cleft; the small space between the presynaptic terminal button
and the postsynaptic dendritic spine, axon, or soma.

Answer 16

Synaptic gap

Question 17

Groups of neurotransmitters packaged together and located within the terminal button.

Answer 17

Synaptic vesicles

Question 18

The part of the end of the axon that form synapses with postsynaptic dendrite, axon, or soma.

Answer 18

Terminal button

Question 19

Specific membrane potential that the neuron must reach to initiate an action potential.

Answer 19

Threshold of excitation