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104 Cards in this Set
- Front
- Back
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What is a 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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What is motor neuron?
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A neuron located within the central nervous system that controls the contraction of a muscle or the secretion of a gland.
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What is an interneuron?
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A neuron located entirely within the central nervous system.
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What is the central nervous system (CNS)?
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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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What is the peripheral nervous system (PNS)?
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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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What is the soma?
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The cell body of a neuron, which containes the nucleus.
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What is a dendrite?
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A branched, treelike structure attached to the soma of a neuron; receives information from the terminal buttons of other neurons.
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What is a synapse?
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A junction between the terminal button of an axon and the membrane of another neuron.
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What is an axon?
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The long, thin, cylindrical structure that conveys information from the soma of a neuron to its terminal buttons.
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What is a multipolar neuron?
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A neuron with one axon and many dendrites attached to its soma.
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What is a bipolar neuron?
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A neuron with one axon and one dendrite attached to its soma.
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What is an 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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What is a terminal button?
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The bud at the end of a branch of an axon; forms synapses with another neuron; sends information to that neuron.
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What is a transmitter substance/neurotransmitter?
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A chemical that is released by a terminal button; has an excitatory or inhibitory effect on another neuron.
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What is a membrane?
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A structure consisting principally of lipid molecules that defines the outer boundaries of a cell and also constitutes many of the cell organelles, such as the Golgi apparatus.
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What is a nucleus?
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A structure in the central region of a cell, containing the nucleolus and chromosomes.
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What is a nucleolus?
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A structure within the nucleus of a cell that produces the ribosomes.
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What is a ribosome?
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A cytoplasmic structure, made of protein, that serves as the site of production of proteins translated from mRNA.
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What is a chrosome?
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A strand of DNA, with associated proteins, found in the nucleus; carries genetic information.
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What is deoxyribonucleic acid (DNA)?
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A long, complex macromolecule consisting of two interconnected helical strands; along with associated proteins, strands of DNA constitute the chromosomes.
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What is a gene?
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The functional unit of the chromosome, which directs synthesis of one or more proteins.
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What is messenger ribonucleic acid (mRNA)?
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A macromolecule that delivers genetic information concerning the synthesis of a protein from a portion of a chromosome to a ribosome.
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What is an enzyme?
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A molecule that controls a chemical reaction, combining two substances or breaking a substance into two parts.
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What is cytoplasm?
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The viscous, semi-liquid substance contained in the interior of a cell.
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What are mitochondria?
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An organelle responsible for extracting energy from nutrients.
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What is adenosine triphosphate (ATP)?
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A molecule of prime importance to cellular energy metabolism, its breakdown liberates energy.
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What is the endoplasmic reticulum?
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Parallel layers of membrane found within the cytoplasm of a cell.
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What does the rough endoplasmic reticulum contain and what is its purpose?
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The rough endoplasmic reticulum contains ribosomes and is involved with production of proteins that are secreted by the cell.
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What is the purpose of the smooth endoplasmic reticulum?
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The smooth endoplasmic reticulum is the site of synthesis of lipids and provides channels for the segregation of molecules involved in various cellular processes.
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What are the 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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What is exocytosis?
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The secretion of a substance by a cell through means of vesicles; the process by which neurotransmitters are secreted.
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What is a lysosome?
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An organelle surrounded by membrane; contains enzymes that break down waste products.
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What is the cytoskelton?
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Formed of microtubules, neuroflaments, and microflaments, linked to each other and forming a cohesive mass that gives a cell its shape.
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What is a microtubule?
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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.
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What is a neurofilament?
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One of the fibers of the cytoskeleton, made of long, continuous strands of protein similar to those found in hair.
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What is a microfilament?
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The thinnest of the fibers of the cytoskeleton; forms a meshwork just inside the membrane that holds membrane-bound proteins in place.
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What is axoplasmic transport?
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An active process by which substances are propelled along microtubules that run the length of the axon.
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What is anterograde?
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In a direction along an axon from the cell body toward the terminal buttons.
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What is retrograde?
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In a direction along an axon from the terminal buttons toward the cell body.
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What are the glia?
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The supporting cells of the central nervous system.
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What is an 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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What is phagocytosis?
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The process by which cells engulf and digest other cells or debris caused by cellular degneration.
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What is an oligodendrocyte?
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A type of glial cell in the central nervous sytem that forms myelin sheaths.
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What is a 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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What is the node of Ranvier?
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A naked portion of a myelinated axon, between adjacent oligodendroglia or Schwann cells.
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What are the microglia?
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The smallest of glial cells; acts as phagocytes and protects the brain from invading microorganisms.
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What is a 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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What is the blood-brain barrier?
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A semipermeable barrier produced by the cells in the walls of the capillaries in the brain.
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What is the area postrema?
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A region of the medulla where the blood-brain barrier is weak; poisons can be detected there and can initiate vomiting.
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What is an electrode?
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A conductive medium that can be used to apply electrical stimulation or to record electrical potentials.
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What is a microelectrode?
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A very fine electrode, generally used to record activity of individual neurons.
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What is the membrane potential?
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The electrical charge across a cell membrane; the difference in electrical potential inside and outside the cell.
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What is an oscilloscope?
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A laboratory instrument capable of displaying a graph of voltage as a function of time on the face of a cathode ray tube.
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What is the resting potential?
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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
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What is depolarization?
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Reduction (toward zero) of the membrane potential of a cell from its normal resting potential.
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What is hyperpolarization?
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An increase in the membrane potential of a cell, relative to the normal resting potential.
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What is the 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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What is the threshold of excitation?
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The value of the membrane potential that must be reached in order to produce an action potential.
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What is diffusion?
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The movement of molecules from regions of high concentration to regions of low concentration.
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What is an electrolyte?
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An aqueous solution of a material that ionizes - namely, a soluble acid, base or salt.
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What is an ion?
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A charged molecule.
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What is a cation?
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A positively charged ion.
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What is an anion?
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A negatively charged ion.
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What is electrostatic pressure?
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The attractive force between atomic particles charged with opposite signs, or the repulsive force between atomic particles charged with the same sign.
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What is intracellular fluid?
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The fluid contained within cells.
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What is extracellular fluid?
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Body fluids located outside of cells.
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What is a sodium-potassium transporter?
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A protein found in the membrane of all cells that extrude sodium ions from and transports potassium ions into the cell.
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What is an ion channel?
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A specialized protein molecule that permits specific ions to enter or leave cells.
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What is a voltage-dependent ion channel?
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An ion channel that opens or closes according to the value of the membrane potential?
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What is the all-or-none law?
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The principle that once an action potential is triggered in an axon, it is propagated, without decrement, to the end of the fiber.
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What is the rate law?
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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 that axon fires.
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What are cable properties?
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The passive conduction of electrical current, in a decremental fashion, down the length of an axon.
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What is saltatory conduction?
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Conduction of action potentials by myelinated axons. The action potential "jumps" from one node of Ranvier to the next.
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What is postsynaptic potential?
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Alterations in the membrane potential of a postsynaptic neuron, produced by liberation of transmitter substance at the synapse.
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What is a neuromodulator?
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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.
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What is the endocrine gland?
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A gland that liberates its secretions into the extracellular fluid around capillaries and hence into the bloodstream.
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What is a target cell?
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The type of cell that is directly affected by a hormone or nerve fiber?
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What is a binding site?
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The location on a receptor protein to which a ligand binds.
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What is a ligand?
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A chemical that binds with the binding site of a receptor.
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What is a dendritic spine?
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A small bud on the surface of a dendrite, with which a terminal button from another uenuron forms a synapse.
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What is the presynaptic membrane?
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The membrane of a terminal button that lies adjacent to the postsynaptic membrane.
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What is the postsynaptic membrane?
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The cell membrane opposite the terminal button in a synapse; the membrane of the cell that receives the message.
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What is the synaptic cleft?
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The space between the presynaptic membrane and the postsynaptic membrane.
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What is a synaptic vesicle?
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A small, hollow, beadlike structure found in terminal buttons; contains molecules of a neurotransmitter.
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What is the release zone?
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A region of the interior of the postsynaptic membrane of the synapse to which synaptic vesicles attach and release their neurotransmitter into the synaptic cleft.
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What is the cisterna?
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A part of the Golgi apparatus; through the process of pinocytosis, it receives portions of the presynaptic membrane and recycles them into synaptic vesicles.
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What is pinocytosis?
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The pinching of a bud of cell membrane, which travels to the interior of the cell.
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What is a postsynaptic receptor?
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A receptor molecule in the postsynaptic membrane of a synapse that contains a binding site for a neurotransmitter.
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What is a neurotransmitter-dependent ion channel?
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An ion channel that opens when a molecule of a neurotransmitter binds with a postsynaptic receptor.
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What is an ionotropic receptor?
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A receptor that contains a binding site for a neurotransmitter and an ion channel that opens when a molecule of the neurotransmitter attaches to the binding site.
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What is a metabotropic receptor?
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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 membranes of the cell when a molecule of the neurotransmitter attaches to the binding site.
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What is a G protein?
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A protein coupled to a metabotropic receptor; conveys messages to other molecules when a ligand binds with and activates the receptor.
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What is a second messenger?
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A chemical produced when 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.
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What is reuptake?
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The reentry of a transmitter substance just liberated by a terminal button back through its membrane, thus terminating the postsynaptic potential.
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What is enzymatic deactivation?
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The destruction of a transmitter substance by an enzyme after its release - for example, the destruction of acetylcholine by acetylcholinesterase.
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What is acetylcholine (ACh)
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A neurotransmitter found in the brain, spinal cord, and parts of the peripheral nervous system; response for muscular contraction.
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What is acetylcholinesterase (AChE)?
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The enzyme that destroys acetylcholine soon after it is liberated by the terminal buttons, thus terminating the postsynaptic potential.
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What is neural integration?
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The process by which inhibitory and excitatory postsynaptic potentials summate and control the rate of firing of a neuron.
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What is an autoreceptor?
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A receptor molecule located on a neuron that responds to the neurotransmitter relased by that neuron.
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What is presynaptic inhibition?
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The action of a presynaptic terminal button in an axoaxonic synapse; reduces the amount of neurotransmitter relased by the postsynaptic terminal button.
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What is presynaptic facilitation?
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The action of a presynaptic terminal button in an axoaxonic synpase; increases the amount of neurotransmitter released by the postsynaptic terminal button.
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What is a gap junction?
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A special junction between cells that permits direct communication by means of electrical coupling.
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What is a peptide?
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A chain of amino acids joined together by peptide bonds.
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What is a steroid?
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A chemical of low molecular weight, derived from cholesterol. Steroid hormones affect their target cells by attaching to receptors found within the cell.
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