The Eye 1. Lacrimal apparatus ï‚ Lacrimal glands Superior and lateral in each eye...

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Transcript of The Eye 1. Lacrimal apparatus ï‚ Lacrimal glands Superior and lateral in each eye...

Chapter 24

The Eye1Lacrimal apparatusLacrimal glandsSuperior and lateral in each eyeProduces tearsSeveral small ducts liberate the tear continuallyExcretory ducts

Accessory structures of the eye2

Lacrimal ApparatusLacrimal canalMedial in each eyeLacrimal sacNasolacrimal ductTearsSalt solutionContains lysozyme and antibodiesCleanse, protect, moisten and lubricate the eye ball3

Accessory structures of the eyePalpebraeLateral canthusMedial canthusCaruncle contains sweat and sebaceous glands4

Accessory structures of the eyeEyelashesCiliary glandsModified sweat glands between the eyelashesMeibomian or tarsal glandsPosterior to the eyelashes. Secrete oil5

Accessory structures of the eyeStyAcute inflammation of the ciliary or meibomian glandChalazioChronic inflammation of the meibomian gland

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Accessory structures of the eyeConjunctivaPalpebralOcular or bulbarIt is a mucosa that secretes mucusConjunctivites Inflamation of the conjunctivaExtrinsic muscles of the eyeControl eye movement

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Internal Anatomy of the eyeOuter fibrous tunicDense avascular connective tissueSclera CorneaTransparent, anterior most portion

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Internal Anatomy of the eyeMiddle vascular tunic (uvea)IrisColored part of the eyeSmooth muscle acting as a diaphragm Ciliary bodyCiliary muscles control the shape of the lensCiliary processes secretes aqueous humorSuspensory ligaments

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Internal Anatomy of the eyeChoroidPosteriormost partContain melaninTapetum lucidum (only in animals)Inner sensory tunic (Retina)Pigmented layerCovers the choroid

10Internal Anatomy of the eyeNeural layerRods photoreceptors cells for dim light. Perceives gray tonesCones photoreceptors cells for color. They need high amount of lightOptic disc blind spot. Emergency of the optic nerveMacula lutea high concentration of cones. Fovea

11Internal Anatomy of the eyeLensHeld by the suspensory ligaments. Attaches to the ciliary body.Catarats lens become opaque and hard12Internal Anatomy of the eyeAnterior segmentAqueous humor clear fluid formed by the ciliary process. It provides nutrients for the lens and cornea.Scleral venus sinus (canal of Schlemm) absorbs the aqueous humorGlaucoma increased intraocular pressurePosterior segmentVitreous humor helps to keep the retina in place

13Figure 17.4a, bThe Sectional Anatomy of the Eye

14Microscopic anatomy of the retinaPigmented epithelial layerLocated between the choroid and neural layerNeural layerPhotoreceptors rods and conesBipolar neuronsGanglion neurons15Microscopic anatomy of the retina

16Visual Pathways to the brainOptic nerveOptic chiasmaIt is the crossing of the fibers of the optic nerveOptic tractThalamusOptic radiationVisual cortex located on the occipital lobe17Visual Tests and ExperimentsBlind SpotWhen the image fall on the optic disc18Visual Tests and ExperimentsRefraction of the light raysCorneaLens Vitreous humorAccommodation of the lensNear-point accommodationPresbiopia difficult focus for close vision because of decreased lens elasticity19Visual Tests and ExperimentsVisual acuitySnellen chartEmmetropy MyopiaHyperopiaAstigmatismIrregularity in the curvatures of the lens and/or cornea

20Visual Tests and ExperimentsColor blindnessThree cone types- red, green and blueBinocular visionThree dimensional visionAccuracy of locating objectsDepth perceptionPanoramic vision21Visual Tests and ExperimentsExtrinsic muscles of the eyeConvergenceMedial eye movements for near visionKeep moving objects focused on the fovea

22Visual Tests and ExperimentsPupillary reflexPhotopupillary reflexConstriction of the pupils when the retina is illuminated by a bright lightIntrinsic muscles of the eyeAccommodation pupillary reflexChange of the pupil diameter for near focus

23Eye DissectionWHOLE EYECorneaScleraOptic nerveExtrinsic muscles24Eye DissectionFRONTAL CUTHumors: aqueous, vitreousLensCiliary bodyIrisPupilChoroid Retina Posterior cavity

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