Special Senses



Special SensesThe SensesGeneral senses of touch Special senses 4351020107950 The Eye and Vision______ of all sensory receptors are in the eyesEach eye has over a ___________ nerve fibersProtection for the eyeMost of the eye is enclosed in a __________ ________A cushion of ______ surrounds most of the eyeAccessory Structures of the Eye Tarsal glands lubricate the eyeCiliary glands are located between the eyelashes Membrane that lines the eyelidsConnects to the surface of the eyeSecretes mucus to lubricate the eye2872105102870Lacrimal apparatus_____________gland—produces lacrimal fluidLacrimal _____________—drain lacrimal fluid from eyesLacrimal _____________—provides passage of lacrimal fluid towards nasal cavity___________________—empties lacrimal fluid into the nasal cavityFunction of the lacrimal apparatus ___________________________________ the eyeEmpties into the nasal cavityProperties of lacrimal fluidDilute _____________ solution (tears)Contains antibodies and lysozymeExtrinsic eye muscles _________ muscles attach to the outer surface of the eyeProduce eye _____________________Structure of the EyeLayers forming the wall of the eyeball Outside layer Middle layer Inside layerStructure of the Eye: The Fibrous Layer White __________________ tissue layerSeen anteriorly as the “___________________________” ________________________, central anterior portionAllows for ________________ to pass through_____________ itself easilyThe only human tissue that can be _________________ without fear of rejectionStructure of the Eye: Vascular Layer_________________ is a blood-rich nutritive layer in the posterior of the eye_________________ prevents light from scatteringModified anteriorly into two structures_________________ —smooth muscle attached to lens____________—regulates amount of light entering eyePigmented layer that gives eye _____________Pupil—rounded __________________ in the irisStructure of the Eye: Sensory Layer219456022225Retina contains two layersOuter __________ layerInner __________ layerContains receptor cells (photoreceptors)________________Signals pass from photoreceptors via a two-neuron chainBipolar neuronsGanglion cellsSignals leave the retina toward the brain through the ______________ nerve______________ (blind spot) is where the optic nerve leaves the eyeball______________ see images focused on the optic discNeurons of the retina and vision RodsMost are found towards the __________ of the retinaAllow ______ light vision and _____________ visionAll perception is in ___________ tonesConesAllow for ___________ ______________ visionDensest in the ________________ of the retina_______________—area of the retina with only cones____photoreceptor cells are at the optic disc, or blind spotCone sensitivity ____________ types of conesDifferent cones are sensitive to different wavelengthsColor _________ is the result of the lack of one cone typeLens____________ crystal-like structureHeld in place by a suspensory ligament attached to the ciliary bodyCataracts result when the lens becomes hard and __________ with ageVision becomes _________ and distortedEventually causes blindness in affected eyeTwo Segments, or Chambers, of the EyeAnterior (________________) segmentAnterior to the lensContains aqueous humorPosterior (_______________) segmentPosterior to the lensContains vitreous humorAnterior Segment________________ humor______________ fluid found between lens and corneaSimilar to blood _____________Helps maintain intraocular _________________Provides ________________ for the lens and corneaReabsorbed into venous blood through the scleral venous sinus, or canal of SchlemmPosterior Segment_________________ humor_______________ substance posterior to the lensPrevents the eye from ________________Helps maintain intraocular pressureOphthalmoscopeInstrument used to illuminate the interior of the eyeballCan detect diabetes, arteriosclerosis, degeneration of the optic nerve and retinaPathway of Light Through the EyeLight must be focused to a point on the ______________ for optimal visionThe eye is set for ______________ vision (over 20 feet away)Accommodation—the _____________ must change ________ to focus on closer objects (less than 20 feet away)Image formed on the retina is a real imageReal images are_______________ from left to right _______________ down_______________ than the objectVisual Fields and Visual PathwaysOptic __________________ Location where the optic nerves _______________Fibers from the medial side of each eye cross over to the opposite side of the brainOptic __________________ Contain fibers from the lateral side of the eye on the same side and the medial side of the opposite eyeEye ReflexesInternal muscles are controlled by the ____________________ nervous systemBright light causes pupils to ______________ through action of radial, circular, and ciliary musclesViewing close objects causes accommodationExternal muscles control eye ____________ to follow objectsViewing close objects causes _____________________ (eyes moving medially)A Closer Look______________—eye focuses images correctly on the retina______________ (nearsighted)Distant objects appear ____________ Light from those objects fails to reach the retina and are focused in _____________ of itResults from an eyeball that is too long______________ (farsighted)Near objects are blurry while distant objects are clearDistant objects are focused ______________ the retinaResults from an eyeball that is too short or from a “lazy lens”_______________________Images are ___________________Results from light focusing as lines, not points, on the retina due to unequal curvatures of the cornea or lensHomeostatic Imbalances of the EyesNight blindness—inhibited rod function that hinders the ability to see at nightColor blindness—genetic conditions that result in the inability to see certain colors Due to the lack of one type of cone (partial color blindness)Cataracts—when lens becomes hard and opaque, our vision becomes hazy and distortedGlaucoma—can cause blindness due to increasing pressure within the eyeThe EarHouses two senses Receptors are ____________________________Different organs house receptors for each senseAnatomy of the EarThe ear is divided into three areas The External EarInvolved in __________________________ onlyStructures of the external ear__________________ (pinna)External acoustic meatus (______________________)Narrow chamber in the temporal boneLined with skin and _______________________ (wax) glandsEnds at the ____________________________The Middle Ear (Tympanic Cavity)_____________________ cavity within the temporal boneOnly involved in the sense of ____________________Two tubes are associated with the inner earThe opening from the auditory canal is covered by the tympanic membraneThe _______________________________ tube connecting the middle ear with the throatAllows for equalizing ___________________ during yawning or swallowingThis tube is otherwise __________________Bones of the Middle Ear (Tympanic Cavity)Three bones (_____________________) span the cavity______________ (hammer)______________ (anvil)______________ (stirrip)FunctionVibrations from eardrum move the _____________ _____________ _____________ _____________ 273812046990Inner Ear or Bony LabyrinthIncludes sense organs for _____________ and _____________Filled with _________________A maze of bony chambers within the temporal bone_____________ _____________ _____________ ____________Organs of EquilibriumEquilibrium receptors of the inner ear are called the _____________ apparatusVestibular apparatus has two functional parts_____________ equilibrium_____________ equilibriumStatic Equilibrium_____________ —receptors in the vestibuleReport on the _____________ of the headSend information via the vestibular nerveAnatomy of the maculaeHair cells are embedded in the _____________ membrane_________(tiny stones) float in a gel around the hair cellsMovements cause otoliths to ___________ the hair cellsDynamic Equilibrium_____________ _____________ —receptors in the semicircular canalsTuft of hair cells_____________ (gelatinous cap) covers the hair cellsAction of angular head movementsThe cupula _____________ the hair cellsAn impulse is sent via the vestibular nerve to the cerebellumOrgans of HearingOrgan of _____________Located within the _____________Receptors = hair cells on the basilar membrane_____________ tectorial membrane is capable of _____________ hair cellsCochlear nerve attached to hair cells transmits nerve impulses to auditory cortex on temporal lobeMechanism of HearingVibrations from sound waves move _____________ membraneHair cells are _____________ by the membraneAn _____________ ___________ starts in the cochlear nerve_____________ stimulation can lead to adaptationOlfaction—The Sense of SmellOlfactory receptors are in the __________ of the nasal cavityNeurons with long _______________Chemicals must be ____________ in mucus for detectionImpulses are transmitted via the olfactory nerveInterpretation of smells is made in the cortexThe Sense of TasteTaste____________ house the receptor organsLocation of taste budsMost are on the __________________________ palate_____________ The Tongue and TasteThe tongue is covered with projections called papillae_____________ papillae—sharp with no taste buds_____________ papillae—rounded with taste buds_____________ papillae—large papillae with taste budsTaste buds are found on the sides of papillaeStructure of Taste Buds_____________ cells are the receptorsHave gustatory hairs (long _____________)Hairs are stimulated by _____________ dissolved in salivaImpulses are carried to the gustatory complex by several cranial nerves because taste buds are found in different areasFacial nerveGlossopharyngeal nerveVagus nerve239903038100Taste Sensations_____________ receptors(sugars)SaccharineSome amino acids_____________ receptorsAcids_____________ receptorsAlkaloids_____________ receptorsMetal ions _____________Chemical Senses: Taste and SmellBoth senses use _____________Stimulated by chemicals in _____________Taste has _____________ types of receptorsSmell can differentiate a _____________ range of chemicalsBoth senses _____________ each other and respond to many of the _____________ stimuliDevelopmental Aspects of the Special SensesFormed early in embryonic developmentEyes are _____________ of the brainAll special senses are _____________ at birthEye problems_____________ —“crossed eyes” results from unequal pulls by the external eye muscles in babiesOphthalmia neonatorum—conjunctivitis resulting from mother having gonorrhea. Baby’s eyelids are swollen and pus is produced _____________ —“old vision” results from decreasing lens elasticity that accompanies agingEar problems_____________ —type of sensorineural deafness_____________ —ear ossicles fuse ................
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