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55 Cards in this Set
- Front
- Back
Sensory Neuron
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A neuron that detects changes in the external or internal environment and sends information about these changes to the central nervous system
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Motor Neuron
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A neuron located within the central nervous system that controls the contractions of a muscle or the secretions of a gland
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Interneuron
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A neuron located entirely within the central nervous system
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Central Nervous System
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The brain and spinal cord
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Peripheral Nervous System
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That part of the nervous system outside the brain and spinal cord including the nerves attached to the brain and spinal cord
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Basic Structure of a Multipolar Neuron
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Soma
Dendrites Axon Terminal Buttons Synapse |
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Soma
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Contains the nucleus and much of the machinery that provides for the life processes of the cell
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Dendrites
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Serve as recipients of the messages that pass from cell to cell
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Axon
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Carries information from the cell body to the terminal buttons
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Terminal Buttons
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The bud at the end of a branch of an axon
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Synapse
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The junction between the terminal button of an axon and the membrane of another neuron
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Bipolar Neuron
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A neuron with one axon and one dendrite attached to its soma
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Unipolar Neuron
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A neuron with one axon attached to its soma; the axon divides, with one branch receiving sensory information and the other sending the information into the central nervous system
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Membrane
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Lipid molecules that define the outer boundaries of a cell
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Nucleus
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Structure in the central region of a cell that contains the nucleolus and chromosomes
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Nucleolus
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Produces ribosomes
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Ribosomes
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Cytoplasmic structure that serves as the site for production of protiens translated from mRNA
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Chromosome
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A strand of DNA that carries genetic information
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Deoxyribonucleic acid (DNA)
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A complex molecule consisting of two interconnected helical strands
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Gene
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Functional unit of the chromosome, which directs the synthesis of one or more protiens
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Messenger ribonucleic acid (mRNA)
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A macromolecule that delivers genetic information concerning the synthesis of protiens
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Enzyme
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A molecule that controls a chemical reaction, combining two substances or breaking two substances into two parts
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Cytoplasm
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The viscous, semiliquid substance contained in the interior of a cell
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Mitochondria
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Organelles that are responsible for extracting energy from nutrients
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Adenosine triphosphate (ATP)
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A molecule of prime importance to cellular energy metabolism; its breakdown liberates energy
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Endoplasmic Reticulum
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Parallel layers of membrane within the cytoplasm involved in production of protiens and synthesis of lipids
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Golgi apparatus
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A complex of parallel membranes in the cytoplasm that wraps the products of a secretory cell
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Microtubule
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A long strand of bundles of protien filaments arranged around a hollow core and involved in transporting substances
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Overview of Neural Communication
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Sensory neurons detect stimuli (I.e. pain)
When dendrites are stimulated by a noxious stimulus A message is sent down the axon to the terminal buttons located in the spinal cord The terminal button releases a neurotransmitter that excites the interneuron The interneuron sends a message down its axon Its terminal button releases a neurotransmitter that excites the motor neuron The motor neuron sends a message down its axon The release of these neurotransmitters cause a muscle cell to contract The process can be counteracted by inhibition supplied from another source - in this case, the brain |
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Glia
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The supporting cells of the central nervous system
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Astrocyte
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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
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Oligodendracyte
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A type of glial cell in the central nervous system that forms myelin sheaths
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Myelin sheath
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A sheath that surrounds axons and insulates them, preventing messages from spreading between adjacent axons
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Schwann cell
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A cell in the peripheral nervous system that is wrapped around a myelinated axon, providing one segment of its myelin sheath
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Blood-Brain Barrier
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A semi-permeable barrier between the blood and the brain
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Communication within Neurons involves:
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Neurotransmitters triggering an action potential at the dendrites or cell body
Sending the action potential down the axon to the terminal button Consists of a series of alterations in the membrane of the axon that permit various chemicals to move between the interior of the axon and the fluid surrounding it. These exchanges produce electrical currents Using the electrical signals to inform the terminal button to release neurotransmitters Ion Transport |
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Resting potential
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The membrane potential of a neuron when it is not being altered by excitatory or inhibitory postsynaptic potentials
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Depolarization
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Reduction toward zero of the menbrane potential from its normal resting potential
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Hyperpolarization
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An increase in the membrane potential of a cell
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Action potential
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The brief electrical impulse that provides the basis for conduction of information along an axon
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Threshold of excitation
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The value of the membrane potential that must be reached in order to produce an action potential; Membrane potential balances two forces; the force of electrostatic pressure and the force of diffusion
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Diffusion
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Movement of molecules from regions of high concentration to regions of low concentration
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Electrostatic pressure
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The attractive forces between atomic particles charged with opposite signs, or the repulsive forces between atomic particles charged with the same sign
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Concept of chemical transmission
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Chemicals are used to transmit information between cells.
These chemicals include transmitter substances, neural modulators, and hormones. Transmitter substances are released by terminal buttons of neurons and are detected by receptors in the membrane of another cell located a very short distance away. Neural modulators operate in a similar manner but are secreted in larger amounts and diffused over longer distances Hormones are produced in cells located in the endocrine glands Cells that contain receptors for particular hormone are referred to as target cells These chemicals attache to a particular region of the receptor molecules called a binding sight. |
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Structure of Synapses
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Presynaptic membrane
Postsynaptic membrane Synaptic cleft Synaptic vesicle |
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Presynaptic membrane
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The membrane of a terminal button that lies adjacent to the postsynaptic membrane (sends the message)
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Postsynaptic membrane
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The cell membrane opsite the terminal button in a synapse (receives the message)
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Synaptic cleft
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The space between the presynaptic and postsynaptic membranes
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Synaptic vesicle
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A small hollow, beadlike structure found in terminal buttons which contains molecules of a neurotransmitter
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Activation of Receptors
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Transmitters substances produced a depolarization or hyperpolarization in the post synaptic membrane by defusing across the synaptic cleft and attaching to the binding sites of special protein molecules called post synaptic receptors
Once binding occurs the post synaptic receptors open neurotransmitter-dependent ion channels which permit passage of specific ions into or out of the cell |
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Terminating the postsynaptic potential
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Reuptake, Enzymatic deactivation, Acetylcholine, Acetylcholinesterase
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Reuptake
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The re-entry of a neurotransmitter substance liberated by a terminal button back through its membrane
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Enzymatic deactivation
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The destruction of a transmitter substance by an enzyme after release
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Acetylcholine
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A neurotransmitter responsible for muscular contraction
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Acetylcholinesterase
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The enzyme that destroys acetylcholine
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