Term
|
Definition
| A neuron that detects changes in the external or internal environment and sends information about these changes to the central nervous system. |
|
|
Term
|
Definition
| A neuron located within the central nervous system that controls the contraction of a muscle or the secretion of a gland. |
|
|
Term
|
Definition
| A neuron located entirely within the central nervous system. |
|
|
Term
| Central nervous system (CNS) |
|
Definition
| The brain and spinal cord. |
|
|
Term
| Peripheral nervous system (PNS) |
|
Definition
| The part of the nervous system outside the brain and spinal cord, including the nerves attached to the brain and spinal cord. |
|
|
Term
|
Definition
| The cell body of a neuron, which contains the nucleus. |
|
|
Term
|
Definition
| A branched, treelike structure attached to the soma of a neuron; receives information from the terminal buttons of other neurons. |
|
|
Term
|
Definition
| A junction between the terminal button of an axon and the membrane of another neuron. |
|
|
Term
|
Definition
| The long, thin, cylindrical structure that conveys information from the soma of a neuron to its terminal buttons. |
|
|
Term
|
Definition
| A neuron with one axon and many dendrites attached to its soma. |
|
|
Term
|
Definition
| A neuron with one axon and one dendrite attached to its soma. |
|
|
Term
|
Definition
| A neuron with one axon attached to its soma; the axon divides, one branch receiving sensory information and the other sending the information into the central nervous system. |
|
|
Term
|
Definition
| The bud at the end of a branch of an axon; forms synapses with another neuron; sends information to that neuron. |
|
|
Term
|
Definition
| A chemical that is released by a terminal button; has an excitatory or inhibitory effect on another neuron. |
|
|
Term
|
Definition
| A structure consisting principally of lipid molecules that defines the outer boundaries of a cell and also constitutes many of the cell organelles. |
|
|
Term
|
Definition
| The viscous, semiliquid substance contained in the interior of a cell. |
|
|
Term
|
Definition
| An organelle that is responsible for extracting energy from nutrients. |
|
|
Term
| Adenosine triphosphate (ATP) |
|
Definition
| A molecule of prime importance to cellular energy metabolism; its breakdown liberates energy. |
|
|
Term
|
Definition
| A structure in the central region of a cell, containing the chromosomes. |
|
|
Term
|
Definition
| A strand of DNA, with associated proteins, found in the nucleus; carries genetic information. |
|
|
Term
| Deoxyribonucleic acid (DNA) |
|
Definition
| A long, complex macromolecule consisting of two interconnected helical strands; along with associated proteins, strands of DNA constitute the chromosomes. |
|
|
Term
|
Definition
| The functional unit of the chromosome, which directs synthesis of one or more proteins. |
|
|
Term
|
Definition
| Formed of microtubules and other protein fibers, linked to each other and forming a cohesive mass that gives a cell its shape. |
|
|
Term
|
Definition
| A molecule that controls a chemical reaction, combining two substances or breaking a substance into two parts. |
|
|
Term
|
Definition
| An active process by which substances are propelled along the microtubules that run the length of the axon. |
|
|
Term
|
Definition
| A long strand of bundles of protein filaments arranged around a hollow core; part of the cytoskeleton and involved in transporting substances from place to place within the cell. |
|
|
Term
|
Definition
| The supporting cells of the central nervous system. |
|
|
Term
|
Definition
| A glial cell that provides support for neurons of the central nervous system, provides nutrients and other substances, and regulates the chemical composition of the extracellular fluid. |
|
|
Term
|
Definition
| The process by which cells engulf and digest other cells or debris caused by cellular regeneration. |
|
|
Term
|
Definition
| A type of glial cell in the central nervous system that forms myelin sheaths. |
|
|
Term
|
Definition
| A sheath that surrounds axons and insulates them, preventing messages from spreading between adjacent axons. |
|
|
Term
|
Definition
| A naked portion of a myelinated axon, between adjacent ogliodendroglia or Schwann cells. |
|
|
Term
|
Definition
| The smallest of glial cells, act as phagocytes and protect the brain from invading microorganisms. |
|
|
Term
|
Definition
| A cell in the peripheral nervous system that is wrapped around a myelinated axon, providing one segment of its myelin sheath. |
|
|
Term
|
Definition
| A semipermeable barrier between the blood and the brain produced by the cells in the walls of the brain's capillaries. |
|
|
Term
|
Definition
| A region of the medulla where the blood-brain barrier is weak; poisons can be detected there and can initiate vomiting. |
|
|
Term
|
Definition
| A conductive medium that can be used to apply electrical stimulation or to record electrical potentials. |
|
|
Term
|
Definition
| A very fine electrode, generally used to record the activity of individual neurons. |
|
|
Term
|
Definition
| The electrical charge across a cell membrane; the difference in electrical potential inside and outside the cell. |
|
|
Term
|
Definition
| A laboratory instrument that is capable of displaying a graph of voltage as a function of time on the face of a cathode ray tube. |
|
|
Term
|
Definition
| The membrane potential of a neuron when it is not being altered by excitatory or inhibitory postsynaptic potentials; approximately -70 mV in the giant squid axon. |
|
|
Term
|
Definition
| Reduction (toward zero) of the membrane potential of a cell from its normal resting potential. |
|
|
Term
|
Definition
| An increase in the membrane potential of a cell, relative to the normal resting potential. |
|
|
Term
|
Definition
| The brief electrical impulse that provides the basis for conduction of information along an axon. |
|
|
Term
|
Definition
| The value of the membrane potential that must be reached to produce an action potential. |
|
|
Term
|
Definition
| Movement of molecules from regions of high concentration to regions of low concentration. |
|
|
Term
|
Definition
| An aqueous solution of a material that ionizes- namely, a soluble acid, base, or salt. |
|
|
Term
|
Definition
| A charged molecule. Cations are positively charged, and anions are negatively charged. |
|
|
Term
|
Definition
| The attractive force between atomic particles charged with opposite sides or the repulsive force between atomic particles charged with the same side. |
|
|
Term
|
Definition
| The fluid contained within cells. |
|
|
Term
|
Definition
| The fluid contained within cells. |
|
|
Term
|
Definition
| Body fluids located outside of cells. |
|
|
Term
| Sodium-potassium transporter |
|
Definition
| A protein found in the membrane of all cells that extrudes sodium ions from and transports potassium ions into the cell. |
|
|
Term
|
Definition
| A specialized protein molecule that permits specific ions to enter or leave cells. |
|
|
Term
| Voltage-dependent ion channel |
|
Definition
| An ion channel that opens or closes according to the value of the membrane potential. |
|
|
Term
|
Definition
| The principle that once an action potential is triggered in an axon, it is propagated, without decrement, to the end of the fiber. |
|
|
Term
|
Definition
| The principle that variations in the intensity of a stimulus or other information being transmitted in an axon are represented by variations in the rate at which the axon fires. |
|
|
Term
|
Definition
| Conduction of action potentials by myelinated ions. The action potential appears to jump from one node of Ranvier to the next. |
|
|
Term
|
Definition
| Alterations in the membrane potential of a post-synaptic neuron, produced by liberation of neurotransmitter at the synapse. |
|
|
Term
|
Definition
| The location on a receptor protein to which a ligand binds. |
|
|
Term
|
Definition
| A chemical that binds with the binding site of a receptor. |
|
|
Term
|
Definition
| A small bud on the surface of a dendrite, with which a terminal button of another neuron forms a synapse. |
|
|
Term
|
Definition
| The membrane of a terminal button that lies adjacent to the postsynaptic membrane and through which the neurotransmitter is released. |
|
|
Term
|
Definition
| The cell membrane opposite the terminal button in a synapse; the membrane of the cell that receives the message. |
|
|
Term
|
Definition
| The space between the presynaptic membrane and the postsynaptic membrane. |
|
|
Term
|
Definition
| A small, hollow, beadlike structure found in terminal buttons; contains molecules of a neurotransmitter. |
|
|
Term
|
Definition
| A region of the interior of the presynaptic membrane of a synapse to which synaptic vesicles attach and release their neurotransmitter into the synaptic cleft. |
|
|
Term
|
Definition
| A receptor molecule in the postsynaptic membrane of a synapse that contains a binding site for a neurotransmitter. |
|
|
Term
| Neurotransmitter-dependent ion channel |
|
Definition
| An ion channel that opens when a molecule of a neurotransmitter binds with a postsynaptic receptor. |
|
|
Term
|
Definition
| A receptor that contains a binding site for a neurotransmitter and ion channel that opens when a molecule of the neurotransmitter attaches to the binding site. |
|
|
Term
|
Definition
| A receptor that contains a binding site for a neurotransmitter; activates an enzyme that begins a series of events that opens an ion channel elsewhere in the membrane of the cell when a molecule of the neurotransmitter attaches to the binding site. |
|
|
Term
|
Definition
| A protein coupled to a metabotropic receptor; conveys messages to other molecules when a ligand binds with and activates the receptor. |
|
|
Term
|
Definition
| A chemical produced hewn a G protein activates an enzyme; carries a signal that results in the opening of the ion channel or causes other events to occur in the cell. |
|
|
Term
| Excitatory postsynaptic potential (EPSP) |
|
Definition
| An excitatory depolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button. |
|
|
Term
| Inhibitory postsynaptic potential (IPSP) |
|
Definition
| An inhibitory hyperpolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button. |
|
|
Term
|
Definition
| The reentry of a neurotransmitter just liberated by a terminal button back through its membrane, thus terminating the postsynaptic potential. |
|
|
Term
|
Definition
| The destruction of a neurotransmitter by an enzyme after its release- for example, the destruction of acetylcholine by acetylcholinesterase. |
|
|
Term
|
Definition
| A neurotransmitter found in the brain, spinal cord, and parts of the peripheral nervous system; responsible for muscular contraction. |
|
|
Term
|
Definition
| The enzyme that destroys acetylcholine soon after it is liberated by the terminal button, thus terminating the post-synaptic potential. |
|
|
Term
|
Definition
| The process by which inhibitory and excitatory postsynaptic potentials summate and control the rate of firing of a neuron. |
|
|
Term
|
Definition
| A receptor molecule located on a neuron that responds to the neurotransmitter released by that neuron. |
|
|
Term
|
Definition
| The action of a presynaptic terminal button in an axoaxonic synapse; reduces the amount of neurotransmitter released by the postsynaptic terminal button. |
|
|
Term
|
Definition
| The action of a presynaptic terminal button in an axoaxonic synapse; increases the amount of neurotransmitter released by the postsynaptic terminal button. |
|
|
Term
|
Definition
| A naturally secreted substance that acts like a neurotransmitter except that it is not restricted to the synaptic cleft but diffuses through the extracellular fluid. |
|
|
Term
|
Definition
| A chain of amino acids joined together by peptide bonds. Most neuromodulators and some hormones consist of peptide molecules. |
|
|
Term
|
Definition
| A chemical substance that is released by an endocrine gland and that has effects on target cells in other organs. |
|
|
Term
|
Definition
| A gland that liberates its secretions into the extracellular fluid around capillaries and hence into the bloodstream. |
|
|
Term
|
Definition
| The type of cell that contains receptors for a particular hormone and is affected by that hormone. |
|
|
