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

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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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