Neurons Flashcards
A transient all-or-nothing electrical current that is conducted down the axon when the
membrane potential reaches the threshold of excitation.
Action potential
Part of the neuron that extends off the soma, splitting several times to connect with other
neurons; main output of the neuron.
Axon
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.
Electrostatic pressure
A bi-lipid layer of molecules that separates the cell from the surrounding extracellular fluid.
Cell membrane
Part of a neuron that extends away from the cell body and is the main input to the neuron.
Dendrite
A depolarizing postsynaptic current that causes the membrane potential to become more
positive and move towards the threshold of excitation.
Excitatory postsynaptic potentials
The force on molecules to move from areas of high concentration to areas of low
concentration.
Diffusion
A hyperpolarizing postsynaptic current that causes the membrane potential to become more
negative and move away from the threshold of excitation.
Inhibitory postsynaptic potentials
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.
Ionotropic receptor
Substance around the axon of a neuron that serves as insulation to allow the action potential
to conduct rapidly toward the terminal buttons.
Myelin sheath
Proteins that span the cell membrane, forming channels that specific ions can flow through
between the intracellular and extracellular space.
Ion channels
Chemical substance released by the presynaptic terminal button that acts on the postsynaptic
cell.
Neurotransmitters
Collection of nerve cells found in the brain which typically serve a specific function.
Nucleus
The voltage inside the cell relative to the voltage outside the cell while the cell is a rest
(approximately -70 mV).
Resting membrane potential
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.
Sodium potassium pump
Cell body of a neuron that contains the nucleus and genetic information, and directs protein
synthesis.
Soma
Protrusions on the dendrite of a neuron that form synapses with terminal buttons of the
presynaptic axon.
Spines
Junction between the presynaptic terminal button of one neuron and the dendrite, axon, or
soma of another postsynaptic neuron.
Synapse
Also known as the synaptic cleft; the small space between the presynaptic terminal button
and the postsynaptic dendritic spine, axon, or soma.
Synaptic gap
Groups of neurotransmitters packaged together and located within the terminal button.
Synaptic vesicles
The part of the end of the axon that form synapses with postsynaptic dendrite, axon, or soma.
Terminal button
Specific membrane potential that the neuron must reach to initiate an action potential.
Threshold of excitation
