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104 Cards in this Set

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