sensory physiology the eye1
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Sensory Physiology The Eye
Sensory PhysiologyThe Eye
Dr. Indra Kusuma, M.Biomed.
FK-YARSI 2014
Daftar Isi
Video
General Properties of Sensory System
Special Sensory: The Eye
Clinical Focus
Concept Summary
Physiology Quiz
Introduction
Brain
(Input to CNSfrom periphery)
Centr l nervous system (CNS)
Spinal cord
(Output from CNSto periphery)
Afferent division
Peripheral nervous system (PNS)
Efferent division
Sensory stimuli
Visceral stimuli
Somatic nervous system
Organization of the ner vous system
Motor neurons
vided into afferent and efferent divisions. The afferent division carries i nformation to the CNS, apprising it of the external en vironment and providing status reports on internal activi ties being regulated by the n ervous system (a is from ad, meaning "toward," as in advance; ferent mea ns "ca rrying"; th us afferent means "carrying toward"). Instructions from the CNS a re tra ns mi tted via the efferent division to effector organs-the muscles or gla nds that ca rry out th e orders to bring abou t the desired 0
1Skeletalmuscle II
Effector organs (made up of muscle and gland tissu).. .
Stimulus Sensorik
Cahaya
Suara
Suhu
Tekanan
Zat kimia
dll
Modalitas Stimulus
Point of View
Stimulus dirubah menjadi potensialreseptor Transduksi Sinyal
Potesial reseptor yang melebihi ambangmemicu potensial aksi Impuls Saraf
Potensial aksi mengalami integrasi dan modulasi di SSP sensasi dan persepsi
Receptor
Reseptor berperan mendeteksi stimulus: Modalitas spesific energy labeled line coding Intensitas amplitudo stimulus : frekuensi impuls Durasi, tonic vs phasic slow vs fast adaptation Lokasi Receptive field, Lateral Inhibition4 Jenis Reseptor Sensorik: Mekanoreseptor Fotoreseptor Stimulus berupa Foton/Cahaya Kemoreseptor Thermoreseptor
General Concept
Stimulus melebihi ambang memicu potensialaksi
Intensitas dan durasi stimulus mempengaruhi pola potensial aksi di SSP
Lokasi dan modalitas stimulus di kode berdasarkan reseptor mana yang aktif
Jaras sensorik menuju daerah spesifik di korteksserebri berupa receptive field tertentu
SpecialSensory : The Eye
Mata adalah organ sensorik yang menjadireseptor untuk stimulus cahaya
Mata menggunakan lensa dan pupil untuk memfokuskan cahaya pada retina
Vision, adalah proses mulai dari cahaya yang dipantulkan benda menjadi mental image yang kita lihat
Point of View
Cahaya masuk dan difokuskan olehlensa pada retina
Fotoreseptor retina merubahenergi cahaya menjadi sinyal listrik
Sinyal listrik berjalan dalam jarassensorik sebagai impuls saraf
JConjunctiva
Posteriorchamber Anterior--.;.,.-....:.:---Anteriorcavity chamber
Central vein
Zonular fibers of suspensory ligament
Vitreous chamber(posterior cavity)
Source: Barrett KE, Barman S M, Boi tano S, Broo ks H :Ganong :S Re"' ew of MedKol PhysiOlogy.
23 foton:http://www.access m ed icine.com
The internal anatomy of the eye.
(From Fox 51, Human Physiology. McGra w-Hill, 2008.)
Light from distant source
Light fromdistant source Focal length
Figure 49-2
\Point sourceL
Focal points
Bending of light rays at each surface of a convex spher ical len showing that parallel light rays are focused to a focal point
Figure 49-6
The two upper lenses of this figure have the same focal length, but the light rays entering the top lens are parallel,whereas those entering the middle lens are diverging; the effect of parallelversus diverging rays on the focal distance is shown. The bottom lens has far more refractive power than either of the other tvl/o lenses (i.e., has a much shorter focal length), demonstrating that the stronger the lens is, the nearer to the lens the point focus is.
Accomodation
Kontraksi otot siliarismenyebabkanligamensuspensorium relaksasi kapsul lensa menjadi lebih spheris (balooning) akibat elastisitas alami kapsul lensa
Intraocular Fluid System
Cairan intraocular Aqueous humor, di depan lensa Vitreous humor, antara lensa dan retinaKeseimbangan Cairan ditentukan olehAqueous Humor Tekanan Intra Okuler (TIO) Formasi : Epitel prosessus siliaris Transport aktif ion natrium ke ruang interseluler yangdiikuti oleh ion klorida dan bikarbonat (pasif) Kadar solut yang tinggi mendorong osmosis air dari kapiler ke ruang interseluler masuk ke ruang anterior
Aqueous humor IrisFlow of fluid \/Spaces of Fontana
Canal of Schlemm
\\\\Vitreous \humor
- - ---"+-'--Diffusion of fluid and other constituents
\ \ .,:.....-Filtration and diffusion at retinal vessels
Blood veins _ :_
Sclera- .:....
Figure 4 21
Figure 4 19
Formation and flow of fluid in the eye.
Anatomy of the iridocorneal angle, showing the syste:n for outflow of aqueous humor from the eyeball into the conjunctival veins.
Fokus Klinik
HiperopiaMiopiaPresbiopia
KatarakGlaucoma
Lateral geniculate bodyOptic tract
Optic radiationOptic chiasm
Optic nerve
Edinger-PretectalWestphal Ciliary region nucleus ganglion--L
\Pons
--Carotid plexus
_,__ Superior cervical sympathetic ganglion
Figure 51-1
Principal vi sual pathways from the eyes to the ':i' suacortex. _(Mod
IUpper thoracic segmentsof spinal cord
Figure 51-11
--Cervical sympathetic trunk
ified fro:n Polyak SL: The Reti na. Chicago: Umvers1ty of Ch1cago,1941.)
Autonomic innervation of the eye, showing also the reflex arc of the light reflex. (Modified fro11 Ranson SW, Clark SL: Anato11y of the Nervous Syste11 Its Development and Function, 1Oth ed. Philadelphia: WB Saunders, 1959.)
Field of Vision
Lapang pandang adalah areayang terlihat oleh mata :Lapang pandang nasal dantemporal
Bintik buta pada lapang pandang disebabkan fokus cahaya yang jatuh pada diskus optikus
vTemporalNasal field field
I\I
Binocular visual field.sua\ field Right
\ILEFT , IEYE''I \1 \1'
RIGHTEYE
e"' '
Ganglioncell
A
cI---tt----Nasal retina../7'----Temporal retina
tn----:----Optic nerve
\. .;:---- ;-- -0ptic chiasm,...--------':--Optic tract
1----:---Lateral geniculate body of thalamus1---"="'-Optic radiations
---- Primary visual cortexCopyright C 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Occipital cortex
SuperiOr rectus (turns eye upward and inward)
Superior oblique (turns gye downward and outward)
/-.,....., " ...,.,
Medialrectus. .,., (turns gye 1nward)
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