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94 Cards in this Set
- Front
- Back
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action potential
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The electrical signal conducted along axons (or muscle fibers) by which information is conveyed from one place to another in the nervous system.
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chemical synapses
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Synapses that transmit information via the secretion of chemical signals (neurotransmitters).
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convergence
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Innervation of a target cell by axons from more than one neuron.
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dendrite
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A neuronal process arising from the cell body that receives synaptic input.
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divergence
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The branching of a single axon to innervate multiple target cells.
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electrical synapses
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Synapses that transmit information via the direct flow of electrical current at gap junctions.
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ganglion (ganglia)
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Collections of hundreds to thousands of neurons found outside the brain and spinal cord along the course of peripheral nerves.
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gene
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Hereditary unit located on the chromosomes; genetic information is carried by linear sequences of nucleotides in DNA that code for corresponding sequences of amino acids.
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glia
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The support cells associated with neurons (astrocytes, oligodendrocytes, and microglia in the central nervous system; Schwann cells in peripheral nerves; and satellite cells in ganglia).
AKA neuroglia. |
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interneuron
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a neuron in the pathway between primary sensory and primary effector neurons; a neuron whose relatively short axons branch locally to innervate other neurons.
AKA local circuit neuron. |
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local circuit neuron
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neurons whose activity mediates interactions between sensory systems and motor systems; AKA interneuron
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Myelin
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The multilaminated wrapping around many axons formed by oligodendrocytes or Schwann cells.
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nerve
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A collection of peripheral axons that are bundled together and travel a common route.
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neuron
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Cell specialized for the conduction and transmission of electrical signals in the nervous system.
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neurotransmitter
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Substance released by synaptic terminals for the purpose of transmitting information from one nerve cell to another.
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nucleus (nuclei)
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Collection of nerve cells in the brain that are anatomically discrete, and which typically serve a particular function.
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projection neuron
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A neuron with long axons that project to distant targets.
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receptor potential
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The membrane potential change elicited in receptor neurons during sensory transduction.
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Schwann cells
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Neuroglial cells in the peripheral nervous system that elaborate myelin (named after the nineteenth-century anatomist and physiologist Theodor Schwann).
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synaptic cleft
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The space that separates pre- and postsynaptic neurons at chemical synapses.
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synaptic vesicle recycling
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A sequence of budding and fusion reactions that occurs within presynaptic terminals to maintain the supply of synaptic vesicles.
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electrochemical equilibrium
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The condition in which no net ionic flux occurs across a membrane because ion concentration gradients and opposing transmembrane potentials are in exact balance.
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equilibrium potential
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The membrane potential at which a given ion is in electrochemical equilibrium
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ion channels
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Integral membrane proteins possessing pores that allow certain ions to diffuse across cell membranes, thereby conferring selective ionic permeability.
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Nernst equation
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A mathematical relationship that predicts the equilibrium potential across a membrane that is permeable to only one ion.
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overshoot
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The peak, positive-going phase of an action potential, caused by high membrane permeability to a cation such as Na+ or Ca2+
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receptor potential
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The membrane potential change elicited in receptor neurons during sensory transduction.
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resting potential
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The inside-negative electrical potential that is normally recorded across all cell membranes.
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rising phase
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The initial, depolarizing phase of an action potential, caused by the regenerative, voltage-dependent influx of a cation such as Na+ or Ca2+.
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undershoot
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The final, hyperpolarizing phase of an action potential, typically caused by the voltage-dependent efflux of a cation such as K+.
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conduction velocity
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The speed at which an action potential is propagated along an axon.
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membrane conductance
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The reciprocal of membrane resistance. Changes in membrane conductance result from, and are used to describe, the opening or closing of ion channels
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myelination
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Process by which glial cells wrap axons to form multiple layers of glial cell membrane that increase axonal conduction velocity.
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nodes of Ranvier
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Periodic gaps in the myelination of axons where action potentials are generated
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passive current flow
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Current flow across neuronal membranes that does not entail the action potential mechanism
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refractory period
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The brief period after the generation of an action potential during which a second action potential is difficult or impossible to elicit.
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saltatory conduction
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Mechanism of action potential propagation in myelinated axons; so named because action potentials “jump” from one node of Ranvier to the next due to generation of action potentials only at these sites
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tetrodotoxin (TTX)
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An alkaloid neurotoxin, produced by certain puffer fish, tropical frogs, and salamanders, that selectively blocks voltage-sensitive Na+ channels; eliminates the initial Na+ current measured in voltage clamp experiments.
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voltage clamp
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Cell's voltage is held at a fixed spot
Advantage: Can seea mount of current passing by at a particular voltage |
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ATPase pumps
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Membrane pumps that use the hydrolysis of ATP to translocate ions against their electrochemical gradients.
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electrogenic
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Capable of generating an electrical current
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inactivation
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The time-dependent closing of ion channels in response to a stimulus, such as membrane depolarization.
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ion exchangers
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Membrane transporters that translocate one or more ions against their concentration gradient by using the electrochemical gradient of other ions as an energy source.
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ligand-gated ion channels
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Term for a large group of neurotransmitter receptors that combine receptor and ion channel functions into a single molecule.
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macroscopic currents
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Ionic currents flowing through large numbers of ion channels distributed over a substantial area of membrane
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microscopic currents
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Ionic currents flowing through single ion channels
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Na+/K+ transporter
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A type of ATPase transporter in the plasma membrane of most cells that is responsible for accumulating intracellular K+and extruding intracellular Na+. Also known as the Na+ pump
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pore
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A structural feature of membrane ion channels that allows ions to diffuse through the channel.
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voltage-gated
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Term used to describe ion channels whose opening and closing is sensitive to membrane potential.
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Types of voltage gated channels
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Sodium, potassium, calcium
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Types of ligand gated channels
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Acetylcoline, serotonin, gabba, glutamate
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Channelopathies
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Disease caused by altered ion channels
Ex: baby seizures, cardiac arythmia |
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endoplasmic reticulum
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Site of protein synthesis, post translation modification
Smooth and rough-Rough has main site for proteins |
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Four major stages of ATP production
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Glycolysis
Cotransport Krebs cycle Electron transport chain |
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Stage of ATPproduction that yields the most ATP
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Electron transport chain
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Golgi bodies
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Continues post translation modification and helps in neurotransmitter synthesis
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Part of mitochondria that yields majority of ATP production
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Inner layer/convoluted membrane
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Huntington's Disease
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Neurodegenerative (some neurons die) - DUe to gene mutation; Chorea (abnormal movement because of mutations in the caudate nucleus)
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Dendrites
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Small branches that come from the soma; Short, multiple, small, receive information and transmit to soma
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Soma
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Cell body; Integrates info coming from many places
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Axon
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Single, long; Conveys information from soma to next target
Most have myelin covering and high concentration of voltage gated sodium channels |
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Synapses
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When one neuron connects to another
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2 ways to transmit signals in synapse
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Chemical and electrical
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This type of chemical transmission binds to ion channels
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Fast, ionotropic
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This type of chemical transmission binds to a special receptor other than a channel and activates metabolic activation
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Slow, metabotropic
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Synaptic terminals and boutons
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Very end (finger is ST, end of ST is boutons); Release neurotrans. to other cells
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4 types of glial cells
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Estrocyte
Oligodendrocyte Microglia Ependymal |
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Astrocyte-
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Type of glial cell; Chief glial cell and function; Regulate microenvironment, control blood flow
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Oligodendrocyte
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Type of glial cell; Produce myelin; Few branches compared to estrocytes
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Microglia
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Type of glial cell; Soldier - Kills foreign invaders, tiny, proect
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Ependymal
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Type of glial cell; Lining of brain cavities
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CNS disease with glial cells
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MS - Myelination problem - Pain or paralysis
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What free radicals are produced in cells
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Super oxide or hydroxyl
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Conversion enzyme for free radicals
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Superoxide dismutase
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Brain diseases with free radicals
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Huntington's disease, Lu Gherig's disease
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Ion pump
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Pumps against concentration gradient (ex: ATPase)
consumes ATP |
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Ion channel
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pore that only allows passive movement along concentration gradient
Doesn't consume ATP |
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Resting potential
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More negative charge inside cell
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Action potential
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Rapid depolarization/repolarization of the membrane potential back to resting potential
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Synaptic potentials
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Depolarization of post synaptic membrane after releasing neurot
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Sensory receptor potentials
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Depolarization of sensory nerve terminals
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Depolarization
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When membrane potential goes from negative to positive
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Repolarization
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Returning back of membrane potential to resting state
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Hyperpolarization
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Undershoot-Membrane potential goes below resting state
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Threshold
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CRITICAL CURRENT/VOLTAGE that opens voltage gated sodium channels become activated so membrane permeability of ion changes
The level of membrane potential at which an action potential is generated Have to reach threshold to initiate action potential |
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Depolarization due to...
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Opening of voltage gated sodium channels
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Repolarization due to...
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opening of voltage gated potassium channels
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Ohms Law
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V=IR
I=GxVm |
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TTX blocks...
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Sodium channels
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TEA blocks
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potassium channels
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Space constant
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Distance it takes for voltage to drop to 37% of original value
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Time constant
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Amount of time due to change membrane potential from resting to 63% of maximum value
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Refractory period
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Time during which second stimulus can generate another action potential with another stimulus
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Absolute refractory
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Time during which you cant generate another action potential no matter how much stimulus increased
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