Clusters (functional groups) of nerve cell bodies in a centralized nervous system.
One of the most common neurotransmitters;
Functions by binding to receptors and altering the permeability of the postsynaptic membrane to specific ions,
either depolarizing or hyperpolarizing the membrane.
Nodes of Ranvier
Gap in the myelin sheath of certain axons where an ACTION POTENTIALS may be GENERATED.
In saltatory conduction, an action potential is generated at each node, appearing to "jump" along the axon from node to node.
A change in a cell's membrane potential such that the INSIDE of the membrane BECOMES MORE NEGATIVE relative to the outside.
Hyperpolarization REDUCES the chance that a neuron will transmit a nerve impulse.
Equilibrium Potential (Eion)
The magnitude of a cell's membrane voltage at equilibrium;
calculated using the Nernst Equation.
Peripheral Nervous System
The sensory and motor neurons that connect to the central nervous system.
A neurotransmitter, SYNTHESIZED FROM the amino acid TRYPTOPHAN, that functions in the central nervous system.
A neurotransmitter derived from an amino acid.
A molecule that is RELEASED FROM the SYNAPTIC TERMINAL of a neuron at a chemical synapse, diffuses across the synaptic cleft, and binds to the POSTSYNAPTIC CELL, triggering a response.
Gamma-Aminobutyric Acid (GABA)
An Amino acid that functions as a CNS neurotransmitter in the central nervous system of vertebrates
A type of glial cell that FORMS INSULATING MYLEIN SHEATHS around the AXONS OF NEURONS in the peripheral nervous system.
A typically long extension, or process, of a neuron that carries nerve impulses AWAY FROM the cell body TOWARD target cells
Ligand-Gated ion channel
A transmembrane protein containing a pore that opens or closes as it changes shape in reponse to a signaling molecule (ligand), allowing or blocking the flow of specific ions;
also called an IONOTROPIC RECEPTOR
A nerve cell that recieves information from the internal or external environment and transmits signals to the Central Nervous System.
an electric signal that propagates (TRAVELS) along the membrane of a neuron or other cell as a nongraded (ALL-OR-NONE) depolarization.
A nerve cell that TRANSMITS SIGNALS from the brain or spinal cord to the muscled or glands.
In a neuron, A SHIFT in the membrane potential that has an amplitude proportional to signal strength and that decays as it spreads.
The junction where a neuron communicates with another cell across a narrow gap via a neurotransmitter or an electrical coupling.
A catecholamine that is chemicalls and functionally similar to epinephrine and acts as a hormone or neurotransmitter;
also known as NORADRENALINE
A transmembrane protein channel that allows a specific ion to diffuse across the membrane down its concentration or electrochemical gradient.
A change in a cell's membrane potential such that the inside of the membrane is made less negative relative to the outside.
Ex. a neuron membrane is depolarized if a stimulus decreased its voltage from the resting potential of -70mV in the direction of 0V
An amino acid that functions as a neurotransmitter in the Central Nervous System.
The potential that an excitable cell membrans must reach for an action potential to be initiated.
The membrane potential characteristic of a nonconducting excitable cell, with the inside of the cell more negative than the outside.
Central Nervous System (CNS)
The portion of the nervous system where signal integration occurs;in vertebrate animals, the BRIAN & SPINAL CORD
A neurotransmitter that is a catecholamine, like epinephrine and norepinephrine
An association neuron; a nerve cell within the CNS that forms synapses with sensory and/or motor neurons and integrates sensory input and motor output.
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.
Organ of the CNS where information is processed and integrated.
A type of glial cell that FORMS insulating myelin sheaths around the axons of neurons in the CNS.
A relatively short chain of AA's that serves as a neurotransmitter.
Wrapped around the axon of a neuron, an insulating coat of cell membranes from Schwann cells or Oligodendrocytes.
It is interrupted by nodes of Ranvier, where action potentials are generated.
A nerve cell; the fundamental unit of the nervous system, having structure and properties that allow it to conduct signals by taking advantage of the electrical charge across its plasma membrane.
The part of a neuron that houses the nucleus and most other organelles.
A fiber composed primarily of the bundled axons of PNS neurons.
The short time immediately AFTER an ACTION POTENTIAL in which the NEURON CANNOT RESPOND TO ANOTHER STIMULUS, owing to the INACTIVATION of voltage-gated SODIUM CHANNELS.
Glia (Glial Cells)
Cells of the nervous system that support, regulate, and augment the functions of neurons.
Gated ion Channel
A gated channel for a specific ion.
The OPENING or CLOSING of such channels may ALTER a cell's 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
-the TRANSMEMBRANE MOVEMENT of all charged substances.
Excitatory Postsynaptic Potential (EPSP)
An electrical change (depolarization) in the membrane of a postsynaptic cell caused by the binding of an EXCITATORY neurotransmitter from a presynaptic cell to a postsynaptic receptor;
makes it MORE LIKELY for a postsynaptic cell to generate an action potential
think: excite --> MORE LIKELY to be happy
Inhibitory Postsynaptic Potential (IPSP)
electrical change (usually hyperpolarization) in the membrane of a postsynaptic neuron caused by the binding of an INHIBITORY neurotransmitter from a presynaptic cell to a postsynaptic receptor;
makes it MORE DIFFICULT for a postsynaptic neuron to generate an action potential
think: Inhibit --> prevent/ inc. difficulty
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.
A phenomenon of neural integration in which the MEMBRANE POTENTIAL OF THE POSTSYNAPTIC CELL is determined by the combined effect of EPSP's of IPSP's produced nearly simultaneously by different synapses.
think: sum(add) of EPSPs + IPSPs
Any of several hormones produced in the brain and anterior pituitary that INHIBIT PAIN PERCEPTION
Voltage-Gated ion channels
A specialized ion channel that opens or closes in response to changes in membrane potential.
One of usually numerous, short, highly branched extensions of a neuron that recieve signals from other neurons.