[Week 3] Neurons Flashcards
Action potential
electrical current conducted down the axon when membrane potential reaches threshold of excitation
Axon
carries impulses AWAY from the cell body to other neurons
Cell membrane
A bi-lipid layer of molecules that separates the cell from the surrounding extracellular fluid.
Dendrite
carry neural impulses TO the cell body
Diffusion
The force on molecules to move from areas of high concentration to areas of low concentration.
Electrostatic pressure
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.
Excitatory postsynaptic potentials
A depolarizing postsynaptic current that causes the membrane potential to become more positive and move towards the threshold of excitation.
Inhibitory postsynaptic potentials
A hyperpolarizing postsynaptic current that causes the membrane potential to become more negative and move away from the threshold of excitation.
Ion channels
Proteins that span the cell membrane
Ionotropic receptor
Ion channel that opens to allow ions to permeate the cell membrane under specific conditions
Myelin sheath
fatty tissue composed of glial cells that insulates the axon; facilitates faster communication between neurons
Neurotransmitters
chemical messengers stored in neuron that activate receptors of other neurons
Nucleus
Collection of nerve cells found in the brain which typically serve a specific function.
Resting membrane potential
The voltage inside the cell relative to the voltage outside the cell while the cell is a rest (approximately -70 mV).
Sodium-potassium pump
An ion channel that uses the neuron’s energy (adenosine triphosphate
Soma
Cell body of a neuron that contains the nucleus and genetic information; “powerhouse of the neuron”
Spines
Protrusions on the dendrite of a neuron that form synapses with terminal buttons of the presynaptic axon.
Synapse
space between axon tip of neuron sending message and dendrite of neuron receiving message
Synaptic gap
Also known as the synaptic cleft; the small space between the presynaptic terminal button and the postsynaptic dendritic spine
Synaptic vesicles
Groups of neurotransmitters packaged together and located within the terminal button.
Terminal button
end of axon; forms synapses with postsynaptic dendrites; discharges and recycles neurotransmitters
Threshold of excitation
Specific membrane potential that the neuron must reach to initiate an action potential.
