special senses week 12 dr. walid daoud a. professor

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Special Senses Special Senses Week 12 Week 12 Dr. Walid Daoud Dr. Walid Daoud A. Professor A. Professor

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Page 1: Special Senses Week 12 Dr. Walid Daoud A. Professor

Special SensesSpecial Senses

Week 12Week 12Dr. Walid DaoudDr. Walid Daoud

A. ProfessorA. Professor

Page 2: Special Senses Week 12 Dr. Walid Daoud A. Professor

Physiological Anatomy of the EyePhysiological Anatomy of the Eye

I- Layers of the eyeI- Layers of the eye::

. .Outer fibrous layer (protective)Outer fibrous layer (protective)::

Cornea, sclera and conjunctivaCornea, sclera and conjunctiva..

. .Middle vascular layer (nutritive)Middle vascular layer (nutritive)::

Iris, ciliary body and choroidIris, ciliary body and choroid..

. .Inner nervous layer ( light perception)Inner nervous layer ( light perception)

Retina, optic disc and nerveRetina, optic disc and nerve..

Page 3: Special Senses Week 12 Dr. Walid Daoud A. Professor

Physiological Anatomy of the EyePhysiological Anatomy of the Eye

II- Ocular chambersII- Ocular chambers::

11 - -Aqueous chamberAqueous chamber::

Anterior to the lensAnterior to the lens..

22 - -Vitreous chamberVitreous chamber::

Behind the lensBehind the lens..

Page 4: Special Senses Week 12 Dr. Walid Daoud A. Professor

The CorneaThe Cornea

Transparent anterior 1/6 of outer layer of eye Transparent anterior 1/6 of outer layer of eye wall. Sensitive to pain, touch, temperaturewall. Sensitive to pain, touch, temperature..Protection of the corneaProtection of the cornea::

11 - -Lids and lid reflex (blinking)Lids and lid reflex (blinking)..22 - -Corneal reflexCorneal reflex..

33 - -Tears contain lysozymes (antibacterial)Tears contain lysozymes (antibacterial)..Nutrition and metabolismNutrition and metabolism::

Cornea is avascular and obtain O2 & glucose Cornea is avascular and obtain O2 & glucose by diffusion from capillariesby diffusion from capillaries..

Page 5: Special Senses Week 12 Dr. Walid Daoud A. Professor

Functions of the corneaFunctions of the cornea

11 - -Refractive power of the eyeRefractive power of the eye..

22 - -Transparency allows passage of lightTransparency allows passage of light..

33 - -Regular curvature forms sharp and clearRegular curvature forms sharp and clear

retinal imageretinal image..

44 - -Eye protectionEye protection::

. . HardnessHardness..

. . Corneal reflexCorneal reflex..

Page 6: Special Senses Week 12 Dr. Walid Daoud A. Professor

Causes of corneal transparencyCauses of corneal transparency

I-AnatomicalI-Anatomical::

- -Regular arrangement of epithelial cellsRegular arrangement of epithelial cells..

- -Regular arrangement of collagen lamellaeRegular arrangement of collagen lamellae..

- -Absence of bl. vessels & myelinated n. fibersAbsence of bl. vessels & myelinated n. fibers

II-PhysicalII-Physical::

--Relative corneal dehydrationRelative corneal dehydration::

Osmotic and metabolic pumpsOsmotic and metabolic pumps

--Refractive index of collagen fibers is nearly the sameRefractive index of collagen fibers is nearly the same

Page 7: Special Senses Week 12 Dr. Walid Daoud A. Professor

Factors maintaining corneal transparencyFactors maintaining corneal transparency

11 - -Vitamin AVitamin A..

22 - -Vitamin B12 (riboflavin)Vitamin B12 (riboflavin)..

33 - -Moistening of corneal surface by tearMoistening of corneal surface by tear

flowflow..

Page 8: Special Senses Week 12 Dr. Walid Daoud A. Professor

Intraocular fluidIntraocular fluid

I- Aqueous humourI- Aqueous humour::

FunctionFunction::

- -Refractive medium of the eyeRefractive medium of the eye..

- - Nutrition and O2 supply of avascularNutrition and O2 supply of avascular

cornea and lenscornea and lens..

- - Maintain intraocular pressure to keepMaintain intraocular pressure to keep

shape of eye ballshape of eye ball..

Page 9: Special Senses Week 12 Dr. Walid Daoud A. Professor

Intraocular fluidIntraocular fluid

II- Vitreous humourII- Vitreous humour::

FunctionsFunctions::

- -Refractive medium of the eyeRefractive medium of the eye..

- - Supports retina and maintain globularSupports retina and maintain globular

shape of eye ballshape of eye ball..

- - Prevents backward displacement of thePrevents backward displacement of the

retinaretina..

Page 10: Special Senses Week 12 Dr. Walid Daoud A. Professor

Uveal TractUveal Tract

11 - -Functions of irisFunctions of iris::

- - Regulate amount of light entering eyesRegulate amount of light entering eyes..

- - Increasing depth of focus by constrictionIncreasing depth of focus by constriction..

- - Limits passage of light to central parts of Limits passage of light to central parts of lens forming clear image on the retina lens forming clear image on the retina..

- - Diagnosis of disease affecting reflexes of Diagnosis of disease affecting reflexes of pupil pupil..

Page 11: Special Senses Week 12 Dr. Walid Daoud A. Professor

Uveal TractUveal Tract

22 - -Functions of Ciliary bodyFunctions of Ciliary body::

- -Ciliary muscleCiliary muscle::

Diopteric power of lensDiopteric power of lens..

Accomodation on near visionAccomodation on near vision..

- -Ciliary processesCiliary processes::

Secrete aqueous humourSecrete aqueous humour..

Page 12: Special Senses Week 12 Dr. Walid Daoud A. Professor

Uveal TractUveal Tract

33 - -Functions of ChoroidFunctions of Choroid::

- -Gives nutrition to retina, ciliary body & irisGives nutrition to retina, ciliary body & iris..

- - Supports the retinaSupports the retina..

- - Gives attachment to ciliary muscleGives attachment to ciliary muscle..

- - Plays role in accommodationPlays role in accommodation . .

- - Choroid pigments prvent reflection of lightChoroid pigments prvent reflection of light

from inside the eyefrom inside the eye..

Page 13: Special Senses Week 12 Dr. Walid Daoud A. Professor

11 - -Coditions associated with Coditions associated with pupillary dilatation (Mydriasis pupillary dilatation (Mydriasis))

22 - -Coditions associated with Coditions associated with pupillary constriction (Miosis) pupillary constriction (Miosis)

Page 14: Special Senses Week 12 Dr. Walid Daoud A. Professor

Crystalline lensCrystalline lens

FunctionsFunctions::

11 - -Enables eye to see near objectsEnables eye to see near objects..

22 - -Refractive media of the eyeRefractive media of the eye..

33 - -Protects retina from harmful effects of UVProtects retina from harmful effects of UV

rays which is absorbed by lens & cornearays which is absorbed by lens & cornea..

Page 15: Special Senses Week 12 Dr. Walid Daoud A. Professor

Errors of RefractionErrors of Refraction

11 - -Myopia (short-sight)Myopia (short-sight)..

22 - -Hypermetropia (far-sight)Hypermetropia (far-sight)..

33 - -Presbyopia (old-sight)Presbyopia (old-sight)..

44 - -AstigmatismAstigmatism..

Page 16: Special Senses Week 12 Dr. Walid Daoud A. Professor

RetinaRetinaPhotoreceptorsPhotoreceptors::

11 - -Cones:Cones: for bright (day) vision for bright (day) vision..

22 - -Rods:Rods: for dim (night) vision for dim (night) vision..

FunctionsFunctions::

11 - -VisionVision..

22 - -Light and accomodation reflexesLight and accomodation reflexes..

33 - -Maintain tone, posture and equilibriumMaintain tone, posture and equilibrium..

Image formed in the retina is inverted but Image formed in the retina is inverted but cerebral cortex interpret it in upright positioncerebral cortex interpret it in upright position..

Page 17: Special Senses Week 12 Dr. Walid Daoud A. Professor

Protective mechanisms of the eyeProtective mechanisms of the eye

11--Lacrimal apparatus: Functions of tearsLacrimal apparatus: Functions of tears::- - Keep cornea & conjunctiva moist & clearKeep cornea & conjunctiva moist & clear..

- - Bacteriolytic action by lysozymeBacteriolytic action by lysozyme..22 - -Eye lids: FunctionEye lids: Function::

- - Regulation of light entering the eyeRegulation of light entering the eye..- - Protection from excessive illumination or FBProtection from excessive illumination or FB

- - Distribution and conduction of tearsDistribution and conduction of tears..33--Corneal reflexCorneal reflex..

Page 18: Special Senses Week 12 Dr. Walid Daoud A. Professor

HearingHearing

Physiological anatomyPhysiological anatomy::

11 - -External earExternal ear..

22 - -Middle ear: bony ossicles & musclesMiddle ear: bony ossicles & muscles

33 - -Inner ear: cochlea and vestibularInner ear: cochlea and vestibular

appartusappartus..

Mechanism of hearingMechanism of hearing..

Page 19: Special Senses Week 12 Dr. Walid Daoud A. Professor

TasteTaste

Chemoreceptors stimulated by chemical Chemoreceptors stimulated by chemical substancessubstances::

Taste buds:Taste buds: 3 types of cells 3 types of cells::

11 - -Taste (gastratory) cellTaste (gastratory) cell..

22 - -Supporting cellSupporting cell..

33 - -Transitional cellTransitional cell..

Page 20: Special Senses Week 12 Dr. Walid Daoud A. Professor

Types of taste sensationTypes of taste sensation

11 - -Sweet tasteSweet taste..

22 - -Salty tasteSalty taste..

33 - -Bitter tasteBitter taste..

44 - -Sour tasteSour taste..

Page 21: Special Senses Week 12 Dr. Walid Daoud A. Professor

Factors affecting taste sensationFactors affecting taste sensation

11 - -Concentration of tasted substanceConcentration of tasted substance..

22 - -ContrastContrast..

33 - -Surface area stimulatedSurface area stimulated..

44 - -TemperatureTemperature..

55 - -OlfactionOlfaction..

66 - -AdaptationAdaptation..

77 - -Individual variationIndividual variation..

Page 22: Special Senses Week 12 Dr. Walid Daoud A. Professor

SmellSmellOlfactory reception cellOlfactory reception cell..Olfactory epitheliumOlfactory epithelium::

11 - -Basal cellBasal cell..22 - -Supporting cellSupporting cell..

33 - -Bowman,s glandBowman,s gland..44 - -ReceptorsReceptors..

Abnormalities of olfactory sensationAbnormalities of olfactory sensation::11 - -AnosmiaAnosmia..

22 - -HyperosmiaHyperosmia . .