Neurons

Question 1

Action potential

Answer 1

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

Question 2

Axon

Answer 2

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

Question 3

Cell membrane

Answer 3

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

Question 4

Dendrite

Answer 4

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

Question 5

Diffusion

Answer 5

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

Question 6

Electrostatic pressure

Answer 6

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.

Question 7

Excitatory postsynaptic potentials

Answer 7

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

Question 8

Inhibitory postsynaptic potentials

Answer 8

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

Question 9

Ion channels

Answer 9

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

Question 10

Ionotropic receptor

Answer 10

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.

Question 11

Myelin sheath

Answer 11

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

Question 12

Neurotransmitters

Answer 12

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

Question 13

Nucleus

Answer 13

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

Question 14

Resting membrane potential

Answer 14

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

Question 15

Sodium-potassium pump

Answer 15

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.

Question 16

Soma

Answer 16

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

Question 17

Spines

Answer 17

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

Question 18

Synapse

Answer 18

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

Question 19

Synaptic gap

Answer 19

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

Question 20

Synaptic vesicles

Answer 20

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

Question 21

Terminal button

Answer 21

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

Question 22

Threshold of excitation

Answer 22

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