Exam 2; Neuroscience Flashcards
Neuroscience
the study of how the brain and nervous system affect our mental processes and behavior
Neurons
cells in the nervous system that transmit information
Myelin
a fatty, waxy substance that insulates portions of some neurons in the nervous system
Glia
brain cells that provide important support functions for the neurons and are involved in the formation of myelin
Cell body
the part of the neuron that contains the nucleus and DNA
DNA
chemical found in the nuclei of cells that contains the genetic blueprint that guides development in the organism
Dendrites
branchlike structures on the head of the neuron that receive incoming signals from other neurons in the nervous system
Axon
a long tail-like structure growing out of the cell body of a neuron that carries action potentials that convey information from the cell body to the synapse
Myelin sheath
the discontinuous segments of myelin that cover the segments of myelin that cover the outside of some axons in the nervous system
Neurotransmitters
chemical messengers that carry neural signals across the synapse
Synapse
the connection formed between two neurons when the axon bulb of one neuron comes into close proximity with the dendrite of another neuron
Presynaptic neuron
the neuron that is sending the signal a synapse in the nervous system
Postsynaptic neuron
the neuron that is receiving the signal at a synapse in the nervous system
Ions
charged particles that play an important role in the firing of an action potentials in the nervous system
Resting potential
the potential difference that exists in the neuron when it is resting (~70mv in mammals)
Threshold of excitation
the potential difference at which a neuron will fire an action potential (55mv)
Action potential
a neural impulse fired by a neuron when it reaches 55mv
All-or-none law
all action potentials are equal in strength; once a neuron begins to fire an action potential, it fires all the way down an axon
Refractory period
a brief period of time after a neuron has fired an action potential during which the neuron is inhibited and unlikely to fire another action potential
Excitation
when a neurotransmitter makes the postsynaptic cell more positive inside, it becomes more likely to fire an action potential
Inhibition
when a neurotransmitter makes the postsynaptic cell more negative inside, it becomes less likely to fire an action potential
Reuptake
the process through which neurotransmitters are recycled back into the presynaptic neuron
Neuromodulators
chemicals in the nervous system that affect neural signaling without directly changing the resting potential of the postsynaptic cell
Acetylcholine (ACh)
a neurotransmitter related to muscle movement and perhaps consciousness, learning, and memory