PENGLIHATAN ( VISION ) YETTY MACHRINA MILAHAYATI DAULAY DEPARTEMEN FISIOLOGI FAKULTAS KEDOKTERAN UNIVERSITAS SUMATERA UTARA

SPESIAL SENSE (Indra Khusus) VISION VISION HEARING HEARING SMELL SMELL TASTE TASTE EQUILIBRIUM EQUILIBRIUM

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PROSES PENGLIHATAN Cahaya masuk melalui pupil → refleks pupil Proses refraksi → proses akomodasi Photoreseptor (retina) N. Opticus thalamus Corteks cerebri area 17 Dan 18 (lobus occipitalis)

Function of the Major Componen Of the Eye Eyelids Eyelids Eyelashes Eyelashes Tears Tears Cornea Cornea Aqueous Humor Aqueous Humor Iris Iris Conjunctiva Conjunctiva Cilliary Body Cilliary Body Suspensory Ligament Suspensory Ligament Pupil Pupil Lensa Lensa Vitreous Humor Vitreous Humor Sclera Sclera Choroid Choroid Retina Retina Fovea Fovea Optic Nerve Optic Nerve Optic Disc Optic Disc

TEARS Tears are produced continously by lacrimal gland Tears are produced continously by lacrimal gland Lacrimal gland lying at the upper lateral corner of under the eyelids Lacrimal gland lying at the upper lateral corner of under the eyelids Lacrimal gland innervate by ANS (parasympatis) Lacrimal gland innervate by ANS (parasympatis) Tears through out each time eyelids close Tears through out each time eyelids close

Tears Flow Lacrimal gland Ductus Lacrimal Anterior surface Lacrimal canal Ductus nasolacrimalis Inferior concha Cavum nasi

Tears Function Protection Protection Keep cornea wet Keep cornea wet Protect the eye from infection Protect the eye from infection

AQUEOUS HUMOR Aqueous Humor is clear liquid material produced about 5ml/day by capillary network within cilliary body Aqueous Humor is clear liquid material produced about 5ml/day by capillary network within cilliary body It nourishes the cornea and lensa It nourishes the cornea and lensa It flows through the pupil and fills tha anterior chamber. Drains into a venous canal between iris and cornea (canal of schlemm), enters the blood It flows through the pupil and fills tha anterior chamber. Drains into a venous canal between iris and cornea (canal of schlemm), enters the blood If there is a blokage in the drainage canal, the excess will accumulate in the anterior cavity, causing the pressure to rise call If there is a blokage in the drainage canal, the excess will accumulate in the anterior cavity, causing the pressure to rise call

PERGERAKAN OTOT MATA M.Rektus medial M.Rektus superior M. Rektus inferior M. Obliq inf M. Obliq sup M. Rektus lat

Kerja otot luar mata Otot Kerja primer Kerja sekunder Rektur lateral Rektus medialis Rektus superior Rektus inferior Obikus superior Oblikus inferior AbduksiAdduksiElevasiDepresiIntorsiEkstorsi Tidak ada Adduksi, intorsi Adduksi, ekstorsi Depresi, abduksi Elevasi, abduksi

Persarafan Otot Pergerakan Mata M. Obliqus inferior M. Obliqus inferior M. Rektus superior M. Rektus superior M. Rektus inferior M. Rektus inferior M. Rektus medial M. Rektus medial M. Obliqus superior M. Obliqus superior M. Rektus lateral M. Rektus lateral N. III (okulomotorius) N. IV (trokhlearis) N. VI ( abducens)

Reflex pupil constriction occurs in bright light to decrease the amount of light entering the eye The circular muscle contract (become shorten), pupil gets smaller Reflex pupil constriction occurs in bright light to decrease the amount of light entering the eye The circular muscle contract (become shorten), pupil gets smaller Bright light  circular muscle contract  miosis Reflex pupil dilatasion occurs in dim light to allow the entrance of more light. The radial muscle contract, pupil size is increase Reflex pupil dilatasion occurs in dim light to allow the entrance of more light. The radial muscle contract, pupil size is increase Dim light  radial muscle contract  dilatasi

PUPIL REFLEX Pupil is controled by iris Pupil is controled by iris Iris contains 2 set of smooth muscle network : Iris contains 2 set of smooth muscle network : 1. Circular muscle (ringlike fashion within the iris) 2. Radial muscle (like bicycle spokes)

Iris muscle is controlled by autonomic nervous system. Parasympatis innervate the circular muscle Sympatis innervate the radial muscle If light directed into the pupil, pupil will constrict and pupil the also other eye (consensual light reflex). It because optic nerve fibers bring impuls to the optic nerve near the lateral genuculate nucleus  midbrain  ipsilateral Edinger-Westphal nucleus and contralateral Edinger-westphal, cilliary gangglion N.III, sebagian dari ganglion ke ciliary body

ORGAN REFRACTIE 1. Cornea 2. Lensa The refractive ability of person’s cornea The refractive ability of person’s cornea Always constan because the curvature of cornea never change. The refactive ability of the lens can be adjusted by chaging its curvature as needed for near or far vision The refactive ability of the lens can be adjusted by chaging its curvature as needed for near or far vision

ACCOMODATION The ability to adjust The ability to adjust Regulated by the cilliary muscle Regulated by the cilliary muscle Cilliary muscle is circular ring of smooth muscle attached to the lens by suspensory ligament Cilliary muscle is circular ring of smooth muscle attached to the lens by suspensory ligament Normal eye : Normal eye : - m. cilliary relax, suspensory lig. Is pulled, lens is flat for far vision (simpatis) - m. cilliary contract, slackening the tension in suspensory lig, lens is more convex and stonger for near vision (parasimpatis)

Anatomy Pemfokusan 233

PHOTORESEPTOR ( retina ) Retina consist of three layers : Retina consist of three layers : 1. outer segment (close to choroid) rod rod cone cone 2. midle segmen Bipolar neuron 3. inner segment Ganglion cell

Ganglion axons membentuk optik nerve Ganglion axons membentuk optik nerve Titik di retina tempat keluarnya saraf optikus dan lewatnya pembuluh darah disebut Diskus optikus (bintik buta) Titik di retina tempat keluarnya saraf optikus dan lewatnya pembuluh darah disebut Diskus optikus (bintik buta) Pada fovea, cahaya yang masuk langsung mencapai fotoreseptor tidak melalui lapisan ganglion dan bipolar ok lapisan ganglion dan bipolar tertarik ke samping Pada fovea, cahaya yang masuk langsung mencapai fotoreseptor tidak melalui lapisan ganglion dan bipolar ok lapisan ganglion dan bipolar tertarik ke samping

Pada fovea hanya ada sel kerucut, sehingga titik ini berfungsi untuk penglihatan tajam. Pada fovea hanya ada sel kerucut, sehingga titik ini berfungsi untuk penglihatan tajam. Daerah tepat disekitar fovea disebut makula lutea Daerah tepat disekitar fovea disebut makula lutea Pada makula lutea, sel -sel kerucut banyak, sehingga ketajaman daerah ini tinggi. Namun tidak lebih besar daripada fovea ok terdapat lapisan bipolar dan sel-sel ganglion diatas makula. Pada makula lutea, sel -sel kerucut banyak, sehingga ketajaman daerah ini tinggi. Namun tidak lebih besar daripada fovea ok terdapat lapisan bipolar dan sel-sel ganglion diatas makula.

OUTER SEGMEN Banyak mengandung fotopigmen Banyak mengandung fotopigmen Terdiri atas protein enzimatik yaitu opsin yang berikatan dengan retinen (derivat vitamin A, red). Terdiri atas protein enzimatik yaitu opsin yang berikatan dengan retinen (derivat vitamin A, red). Retinen = 1 di sel batang Retinen = 1 di sel batang 3 di masing-masing sel kerucut (sel merah,hijau, biru) 3 di masing-masing sel kerucut (sel merah,hijau, biru) FOR COLOR VISION

Photoreceptor Activity in the Dark The plasma membrane chemically channel of photoreceptor respond to internal second massenger, cGMP. Binding cGMP + Na + channels keeps them open. The plasma membrane chemically channel of photoreceptor respond to internal second massenger, cGMP. Binding cGMP + Na + channels keeps them open. When the is absence(stimulation), concentration of cGMP higher  Na + channel open. When the is absence(stimulation), concentration of cGMP higher  Na + channel open. Passive resultant inward Na + leak depolarize the photoreseptor  spread to synapitic terminal (where the photoreceptor’s neurotransmitter is trored)  synaptic terminal voltage gated channels open  Ca 2+ entry  trigger release of neurotransmitter from the synaptic Passive resultant inward Na + leak depolarize the photoreseptor  spread to synapitic terminal (where the photoreceptor’s neurotransmitter is trored)  synaptic terminal voltage gated channels open  Ca 2+ entry  trigger release of neurotransmitter from the synaptic

Inhibitory neurotransmitter that srecreted by amacrine cells are gamma- aminobutyric acid, glycine, dopamine, acetylcholine, dolamine Photoreceptor inhibited of their adequate stimulus (hyperpolarized by light). Photoreceptor inhibited of their adequate stimulus (hyperpolarized by light). Excited absence of stimulation (depolarized by darkness) Excited absence of stimulation (depolarized by darkness)

No light  Concentration cGMP   Na + channels open in outer segmen  Membran depolarization  Spread to the terminal synaptic  Ca 2+ channels open  Release neurotransmitter ((inhibitory neurotransmitter)   Bipolar cells inhibited  No action potential in ganglion cell  No action potential propagation to visual cortex

Light  Activation o fotopigment (rod and cone)  Activation of transducin (G protein)  cGMP   Na + channel closure  Membran hyperpolarizasion (receptor potential)  Spread to the terminal synaps  Closure ca 2+ channels  Release inhibitory neurotrasnmitter   Bipolar cell uninhibited  Graded potential change in bipolar cell  Action potential in ganglion cell  Visual cortex in the occipital lobe of the brain

Benda (memantulkan cahaya)  cornea  lensa  convergensi cahaya  bayangan jatuh tepat di retina (fovea)  aktivasi fotopigmen  a  aktivasi transducin  cGMP   saluran Na + tertutup  hyperpolarisasi membran  Ca 2+ tertutup  Penghambatan pelepasan Neurotransmitter  action potential  bipolar cell  graded potensial pada cell ganglion  N. Opticus  Optic disc  chiasma opticum  tractus geniculatus lateral di thalamus  lobus occipitalis area 17  diasosiakan ke area 18 Benda (memantulkan cahaya)  cornea  lensa  convergensi cahaya  bayangan jatuh tepat di retina (fovea)  aktivasi fotopigmen  a  aktivasi transducin  cGMP   saluran Na + tertutup  hyperpolarisasi membran  Ca 2+ tertutup  Penghambatan pelepasan Neurotransmitter  action potential  bipolar cell  graded potensial pada cell ganglion  N. Opticus  Optic disc  chiasma opticum  tractus geniculatus lateral di thalamus  lobus occipitalis area 17  diasosiakan ke area 18

Kiasma optikum (Optic chiasma) 238

Visual deficits with specific lesions Leftt optic nerve Left eye Right eye Optic chiasm Left optic tract (or radiation)

VISUAL ADAPTATION DARK ADAPTATION DARK ADAPTATION - Break down of photopigment during exposure of sunlight fremendously decreases photoreceptor sensitivity -As a result, the sensitivity of our eyes gradually increase  u can see in the dark

LIGHT ADAPTATION LIGHT ADAPTATION As some of photopigment are rapidly brokendown by intense light, the sensitivIty of the eye decreases and normal contras can once again be detected.

COLOR VISION Cone type = green, blue, red A wave length perceived as blue excite blue cone maximally does not stimulate red or green cone at all. White is a mixture of all wavelength of light Black is the absence of light. We see the same color because we have the same type of cone.

COLOR VISION Visible spectrum Color perceived Percent maximum stimulation Red cones green cones blue cones blue green red

Visual field Visual field is field of view that can be seen without moving the head Visual field is field of view that can be seen without moving the head