Neurons
cell that carries messages throughout the nervous system
Brain
The part of the central nervous system that is located in the skull and controls most functions in the body
Ganglia
groups of nerve cells
Central Nervous System
the portion of the vertebrate nervous system consisting of the brain and spinal cord
Peripheral Nervous System
the sensory and motor neurons that connect the central nervous system to the rest of the body
Sensory Neurons
neurons that carry incoming information from the sense receptors to the central nervous system
Interneurons
central nervous system neurons that internally communicate and intervene between the sensory inputs and motor outputs
Motor Neurons
neurons that carry outgoing information from the central nervous system to the muscles and glands
Dendrites
branching extensions of neuron that receives messages from neighboring neurons
Axon
the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands
Synapse
the junction between two neurons (axon-to-dendrite) or between a neuron and a muscle
Neurotransmitters
Chemicals that transmit information from one neuron to another.
Glial Cells
cells in the nervous system that support, nourish, and protect neurons
Membrane Potential
the difference in electrical charge (voltage) across a cell's plasma membrane due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances.
Resting Potential
the potential difference between the two sides of the membrane of a nerve cell when the cell is not conducting an impulse
Ion Channels
a transmembrane protein channel that allows a specific ion to flow across the membrane down its concentration gradient
Equilibrium Potential (Eion)
the membrane potential at which chemical and electrical forces are balanced for a single ion.
Gated Ion Channels
a pore that allows ions to pass through, but has a mechanism that allows to it be open and closed
Hyperpolarization
The movement of the membrane potential of a cell away from rest potential in a more negative direction.
Depolarization
the process during the action potential when sodium is rushing into the cell causing the interior to become more positive
Graded Potential
A local change in membrane potential that varies directly with the strength of the stimulus, declines with distance.
Action Potential
a neural impulse; a brief electrical charge that travels down an axon
Voltage Gated
Term used to describe ion channels whose opening and closing is sensitive to membrane potential
Threshold
Action potential occurs whenever a depolarization increases the membrane voltage to a particular value
Refractory Period
(neurology) the time after a neuron fires or a muscle fiber contracts during which a stimulus will not evoke a response
Mylein Sheath
fatty membrane covering the neurons axon; good conductor of electricity saves ATP
Oligodendrocytes
produces myelin sheath in Central Nervous System
Schwann Cells
produce myelin in Peripheral Nervous System; (so type of glial cell)
Nodes of Ranvier
Gaps in the myelin sheath of the axons of peripheral neruons. Action potentials can 'hump' from node to node, thus increasing the speed of conduction (saltatory conduction).
Saltatory Conduction
Rapid transmission of a nerve impulse along an axon, resulting from the action potential jumping from one node of Ranvier to another, skipping the myelin-sheathed regions of membrane.
Ligand-gated ion channel
A protein pore in cellular membranes that opens or closes in response to a signaling chemical (its ligand), allowing or blocking the flow of specific ions.
Excitatory postsynaptic potential
a postsynaptic potential that depolarizes the neuronal membrane, making the cell more likely to fire an action potential
Inhibitory postsynaptic potential
a postsynaptic potential that hyperpolarizes the neuronal membrane, making a cell less likely to fire an action potential
Temporal Summation
A phenomenon of neural integration in which the membrane potential of the postsynaptic cell in a chemical synapse is determined by the combined effect of EPSPs or IPSPs produced in rapid succession.
Spatial Summation
The sum of multiple synapses firing at different locations at one time to create a net effect.
Glutamate
a major excitatory neurotransmitter; involved in memory
Gamma-aminobutyric acid
GABA. Inhibitory. Modulates other neurotransmitter systems. Drugs that increase GABA are used to treat anxiety and induce sleep.
Biogenic Amines
Neurotransmitters derived from amino acids
Norepinephrine
helps control alertness and arousal
Dopamine
a monoamine neurotransmitter found in the brain and essential for the normal functioning of the central nervous system--paying attention
Serotonin
a neurotransmitter that affects hunger,sleep,arousal,and mood. appears in lower than normal levels in depressed persons
Neuropeptides
relatively short chains of amino acids, serve as neurotransmitters.
Endorphins
natural, opiatelike neurotransmitters linked to pain control and to pleasure