2 Cells Of The Nervous System Flashcards
Motor neuron
A neuron located within the central nervous system that controls the contraction of a muscle with secretion of a gland.
Sensory neuron
Neuron that detects changes in the external internal environment since information about these changes to the central nervous system.
Interneuron
A neuron located entirely within the central nervous system.
Central nervous system (CNS)
The brain and the spinal cord.
Peripherall nervous system (PNS)
The part of the nervous system outside the brain and spinal cord, including the nerves attached to the brain and spinal cord.
Soma
The cell body of a neuron, which contains the nucleus.
Dendrite
A branch, true like structure attached to the soma of a neuron; receives information from the terminal buttons of other neurons.
Synapse
A junction between the terminal button of an axon and the membrane of another neuron.
Axon
The long, thing, centrical structure that conveys information from the soma of neuron to its terminal buttons.
Multipolar neuron
A neuron with axon and many dendrites attached to it soma.
Bipolar neuron
A neuron with one axon and one dendrite attached to it soma.
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.
Terminal button
The bud at the end of the branch of an axon; form synapses with another neuron; sends information to the neuron.
Neurotransmitter
A chemical that is released by a terminal button; has an excitatory and inhibitory effect on another neuron.
Membrane
A structure consisting principally of lipid molecules that defines he had a boundaries of the cell and also constitutes many of the cell organelles, such as the Golgi apparatus.
Nucleus
A structure in the central region of the cell, containing the nucleolus chromosomes.
Nucleolus
A structure within the nucleus of the cell that produces the ribosomes.
Ribosome
A cytoplasmic structure, made of protein, that serves as a site of production of proteins translated from mRNA.
Chromosome
A strand of DNA, with associated proteins, found in the nucleus; carries genetic information.
Deoxyribonucleic acid (DNA)
A long, complex macromolecule consisting of two interconnected helical strands; along with associated proteins, strands of DNA constitute the chromosomes.
Gene
The functional unit of the chromosome, which directs synthesis of one or more proteins.
Messenger ribonucleic acid (mRNA)
In macromolecule that delivers genetic information concerning the synthesis of a protein from a portion of a chromosome to ribosome.
Enzyme
Molecule that controls the chemical reaction, combining two substances of breaking a substance into two parts.
Non-coding RNA (ncRNA)
A form of RNA that does not include for protein but has functions of its own.
Cytoplasm
The viscous, semiliquid substance contained in the interior of a cell.
Mitochondrion
And organelle that is responsible for extracting energy from nutrients.
Adenosine triphosphate (ATP)
A molecule of prime importance to cellular energy metabolism; its breakdown liberates energy.
Endoplasmic reticulum
Pero layers of membrane found within the cytoplasm of the cell. Rough endoplasmic reticulum contains ribosomes and is involved with production of proteins that are secreted by the cell. Smooth endoplasmic reticulum is a site of synthesis of lipids and provides channels for the segregation of molecules involved in various cellular processes.
Golgi apparatus
A complex of parallel membranes in the cytoplasm that wraps the products of the secretory cell.
Exocytosis
The secretion of a substance by a cell through means of vesicles; the process by which neurotransmitters are secreted.
Lysosome
An organelle surrounded by membrane; contains enzymes that break down waste products.
Cytoskeleton
Formed in microtubules and other protein fibers, linked to each other and forming a cohesive mass that gives a cell its shape.
Microtubule
A long strand of bundles of protein filaments arranged around a hollow core; part of the cytoskeleton involved in transporting substances from place to place within the cell.
axoplasmic transport
An active process by which substances are propelled along microtubules that run the length of the axon.
Anterograde
In a direction along an axon from the cell body toward the terminal buttons.
Retrograde
In a direction along and axon from the terminal buttons toward the cell body.
Glia
The supporting cells of the central nervous system.
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.
Phagocytosis
The process by which cells and engulf and digest other cells or debris caused by cellular degeneration.
Oligodendrocyte
A type of glial cell in the central nervous system that forms myelin sheaths.
Myelin sheathe
A sheathe that surrounds axons and insulates them preventing messages from spreading between adjacent axons.
Node of Ranvier
A naked portion of a myelinated axon between adjacent oligodendroglia or Schwann cells.
Microglia
The smallest of the glial cells; act as phagocytes and protect the brain from invading microorganisms.
Blood-brain barrier
A semi permeable barrier between the blood and the brain produced by the cells in the walls of the brain’s capillaries.
Area postrema
A region of the medulla where the blood-brain barrier is weak; poisons can be detected there and get initiate vomiting.
Electrode
A conductive medium that can be used to apply electrical stimulation or to record electrical potentials.
Microelectrode
A very fine electrical, generally use to record activity of individual neurons.
Membrane potential
Electrical charge across the cell membrane; the difference in electrical potential inside and outside the cell.
Oscilloscope
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.
Resting potential
The membrane potential of neuron when it is not being altered by excitatory or inhibitory postsynaptic potential; approximately -70 mV in the giant squid axon.
Depolarization
Reduction (toward zero) of the membrane potential of the cell from its normal resting potential.
Hyperpolarization
An increase in the membrane potential of the cell, relative to the normal resting potential.
Action potential
The brief electrical impulse that provides the basis for conduction of information along and axon.
Threshold of excitation
The value of the membrane potential that must be reached to produce an action potential.
Diffusion
Movement of molecules regions of high concentration to regions of low concentration.
Electrolyte
An aqueous solution of the material that ionizes – namely, a soluble acid, bass, or salt.
Ion
A charged molecule. Cations are positively charged, and anions are negatively charged.
Electrostatic pressure
The attractive force between atomic particles charged with op. cit. signs of the repulsive force between atomic particles charged with the same sign.
Intracellular fluid
The fluid contained within cells.
Extracellular fluid
Body fluids located outside of cells.
Sodium-potassium transporter
A protein found in the membrane of all cells that extrudes sodium ions from and transports potassium ions into the cell.
Ion channel
A specialized protein molecule that permits specific ions to enter leave cells.
Voltage-dependent ion channel
In ion channel that opens or closes according to the value of the membrane potential.
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.
Rate law
The principle that variations in the intensity of the stimulus or other information being transmitted in an axon are represented by variations in the rate at which that axon fires.
Saltatory conduction
Conduction of action potentials by myelinated axons. The action potential appears to jump from one node of Ranvier to the next.
Postsynaptic potential
Alterations in the membrane potential of the postsynaptic neuron, produced by liberation of neurotransmitter at the synapse.
Blinding site
The location on a receptor protein to which a ligand binds.
Ligand
A chemical that binds with the binding site of a receptor.
Dendritic spine
A small bud on the surface of a dendrite, with which a terminal button of another neuron forms to synapse.
Presynaptic membrane
The membrane of the terminal button that lies adjacent to the postsynaptic membrane and through which the neurotransmitter is released.
Postsynaptic membrane
The cell membrane opposite the terminal button in the synapse; the membrane of the cell that receives the message.
Synaptic cleft
The space between the presynaptic membrane and the postsynaptic membrane.
Synaptic vesicle
A small, hollow, beadlike structure found in terminal buttons; contains molecules of a neurotransmitter.
Release zone
A region of the interior of the presynaptic membrane of the synapse to which synaptic vesicles attached and release the neurotransmitter into the synaptic cleft.
Postsynaptic receptor
A receptor molecule in the postsynaptic membrane of the synapse that contains a binding site for neurotransmitter.
Neurotransmitter-dependent ion channel
An ion channel that opens when a molecule of a neurotransmitter binds with a postsynaptic receptor.
Ionotropic receptor
A receptor that contains a binding site for neurotransmitter and an ion channel that opens when a molecule of the new transmitter attaches to the binding site.
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 membrane of the cell when a molecule of the neurotransmitter attaches to the binding site.
G protein
A protein coupled to a metabotropic receptor; conveys messages to other molecules when an ligand binds with and activates the receptor.
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.
Excitatory postsynaptic potential (EPSP)
An excitatory depolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button.
Inhibitory postsynaptic potential (IPSP)
An inhibitory hyperpolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button.
Reuptake
The reentry of a neurotransmitter just liberated by terminal button back through its membrane, this terminating the postsynaptic potential.
Enzymatic deactivation
The destruction of the neurotransmitter by an enzyme after its release – for example, the destruction of the acetylcholine by as the acetycholinesterace.
Acetylcholine (ACh)
A neurotransmitter found in the brain, spinal cord, and parts of the prefrontal nervous system; responsible for muscular contraction.
Acetycholinesterace (AChE)
The enzyme that destroys acetylcholine soon after it is liberated by the terminal buttons, thus terminating the postsynaptic potential.
Neural integration
The process by which inhibitory and excitatory postsynaptic potentials summate and control the rate of firing of a neuron.
Autoreceptor
A receptor molecule located on a neuron that responds to the neurotransmitter released by that neuron.
Presynaptic inhibition
The action of a presynaptic terminal button in an axoaxonic synapse; reduces the amount of neurotransmitter released by the postsynaptic terminal button.
Presynaptic facilitation
The action of the presynaptic terminal button in an axoaxonic synapse; increases the amount of neurotransmitter released by the postsynaptic terminal button.
Gap junction
A special junction between cells that permits direct communication by means of electrical coupling.
Neuromodulator
A naturally secreted substance to ask like a neurotransmitter except that it is not restricted to the synaptic cleft but diffuses through the extracellular fluid.
Peptide
A chain of amino acids joined together by peptide bonds. Most neuromodulators, and some hormones, consist of peptide molecules.
Hormone
A chemical substance that is released by an endocrine gland that has effects on target cells in other organs.
Endocrine gland
A gland that liberates it secretions into the extracellular fluid around capillaries and hence into the bloodstream.
Target cell
The type of cell that is directly affected by a hormone or other chemical signal.
