2401 Lab Practical 2 - Definitions

Neuroglia (glial cells)
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Terms in this set (114)
Nissl bodiesthe ribosomes, golgi apparatus, rough endoplasmic reticulum and mitochondria of the perikaryon of a typical neuronDendritessensory process of a neuronAxonelongated extension of a neuron that conducts an action potentialAxon HillockIn a multipolar neuron, the portion of the cell body adjacent to the initial segmentCollateralside by sideAxon Terminalstransmit signals to the dendritesSynaptic Clefta gap into which neurotransmitters are released from the axon terminalSynaptic VesiclesTiny pouches or sacs in the axon terminals that contain chemicals called neurotransmitters.MyelinA layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.Neurolemmaouter surface of schwann cellAfferentconducting toward a centerEfferentconducting a fluid or nerve impulse away from an organ or structureGliomatumor of glial cells graded according to degree of malignancyFasciclea discrete bundle of muscle cellsExcitabilityability to receive and respond to stimuliConductivityA material's ability to allow heat to flowResting Membrane Potentialthe membrane of a normal cell under homeostatic conditionsPolarizedReferring to cells that have regional differences in organelle distribution or cytoplasmic composition along a specific axis, such as between the basement membrane and free surface of an epithelial cell.Threshold StimulusThe minimal strength required to cause a contractionDepolarizationA change in the membrane potential from a negative value toward 0 m V.Action PotentialA propagated change in the membrane potential of excitable cells, initiated by a change in the membrane permeability to sodium ionsRepolarizationThe movement of the membrane potential away from a positive value and toward the resting potentialAbsolute Refractory Periodthe interval of time during which a second action potential cannot be initiated, no matter how large a stimulus is repeatedly applied.Relative Refractory Periodthe interval of time during which a second action potential can be initiated, but initiation will require a greater stimulus than before.Nerve Impulsethe message that a neuron carriesElectroencephalogramrecord of the electricity in the brainSomatic Divisioncontrols voluntary muscle movements and sense organs- part of PNSAutonomic Nervous SystemCenters, nuclei, tracts, ganglia, and nerves involved in the unconscious regulation of visceral functions; includes components of the central nervous system and the peripheral nervous system.Sympathetic Brancha part of the ANS that activates the body at times of stressParasympathetic BranchThe branch of the ANS that quiets the bodyGyriridges of the brainSulcishallow grooves that separate gyriFissureselongated grooves or openingsAssociation Tractsconnect different regions of the cerebral cortex within the same hemisphereProjection Tractslink cerebral cortex to inferior brain regions and spinal cordCommisuresconnect gray matter of the two hemispheresFoliaLeaflike folds; the slender folds in the surface of the cerebellar cortexMeningitisinflammation of the meninges - dangerousEncephalitisinflammation of the brain usually caused by a virusHydrocephalusaccumulation of fluid in the brainParaplegiaparalysis of both legs and the lower part of the bodyQuadriplegiaparalysis of all four limbsRamibranches of spinal cordPlexusA network or braid.Sciaticasevere pain in the leg along the course of the sciatic nerve, which travels from the hip to the footFootdropcomplication resulting from extended plantar flexionIntramural Ganglionembedded in tissues of target organParavertebral GanglionSympathetic chain of neurons that run parallel to the spinal cord.Cholinergic Fibersfibers that release AChAdrenergic FibersNerve fibers that release norepinephrineReflex ArcsThe receptor, sensory neuron, motor neuron, and effector involved in a particular reflex; interneurons may be present, depending on the reflex considered.Autonomic Reflexcontrol smooth muscle, cardiac muscle, and glands to maintain homeostasisSomatic Reflexunconscious skeleton muscle responseContralateral Responsewhen a response to a stimuli is given on the opposite side of the bodyIpsilateral Responseany reflex occurring on the same side stimulatedLysozymeAn enzyme, present in some exocrine secretions, that has antibiotic propertiesPalbebraeeyelids -Movable folds that cover the front of the eyeballsConjunctivitisinflammation of the conjunctiva (pink eye)Styepus-filled infection of glands near the eyelid (hordoleum)Cataractclouding of the lens of the eyeGlaucomaincreased intraocular pressureAccomodationAn alteration in the curvature of the lens of the eye to focus an image on the retina.Emmetropicnormal visionMyopianearsightednessHyperopiafarsightednessPresbyopiaimpaired vision as a result of agingBinocular Visionvision using two eyes with overlapping fields of view, allowing good perception of depth.Panoramic VisionWide visual field Common in prey animalsConvergenceIn the nervous system, the innervation of a single neuron by axons from several neurons; most common along motor pathways.Constrictto squeeze tightlyDilate(v.) to make or become larger or wider; to expand uponCerumenear waxOtitis Mediainflammation of the middle earPerilymphfluid contained in the labyrinth of the inner earEndolymphfluid within the labyrinth of the inner earPresbycusisage related hearing lossFrequencythe number of complete wavelengths that pass a point in a given timeIntensityThe amount of energy per second carried through a unit area by a wave.ThresholdLevel of stimulation needed to trigger a neural impulseWeber's TestUse of a tuning fork to help to differentiate the cause of unilateral hearing lossRinne Testhearing test using a tuning fork; checks for differences in bone conduction and air conductionStatic EqulibriumThe sense of body position a person has when not moving.Dynamic Equilibriuma state of balance between continuing processesBalance TestStork standBarany Testrotation test for assessment of vestibular function; testing for nystagmusNystagmusInvoluntary rapid eye movementsVertigoCondition of dizziness, "room spinning"Exteroceptorsdetect external stimuliInteroceptorsdetect internal stimuliVisceroceptorsaka interoceptors. Associated with stimuli affecting visceraBaroreceptorsmonitor blood pressureOsmoreceptorsA receptor sensitive to changes in the osmolarity of plasma (blood)ProprioceptorsSensory organ that monitors the position and movement of skeletal muscles and jointsMechanoreceptorsThe detection of mechanical stimuli, such as touch, pressure, or vibrationThermoreceptorsdetect changes in temperatureNociceptorspain receptorsChemoreceptorsrespond to chemicalsTransducersDevices that convert one kind of energy into anotherPunctate Distributionunequal distribution of receptorsTwo Point Thresholdminimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuliTactile Localizationdetermining which point on skin has been stimulatedAdaptationA trait that helps an organism survive and reproduceAfterimagesSensations that linger after the stimulus is removedReferred Painpain felt in a part of the body other than its actual source