Psikologi faal - PowerPoint Presentation

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Psikologi faalIndera penglihatan 1 & 2

Matrissya HermitaSlide2

RESEPTOR dan PENGINDERAANReseptor : struktur yang menerima stimulus/rangsangan.

Terbagi atas :

Eksteroreseptor

Reseptor yang menerima rangsang/impuls dari luar tubuh.

Umum/biasa : suhu, tekanan.

Khusus : reseptor indera

pengelihatan : retina

penghidu : bulbus olfactorius

pengecap : gema gustatoria

Pendengaran :

cocchlea

Taktil : paccini, meissnerSlide3

Interoseptor Reseptor yang menerima rangsang/impuls yang berkaitan/berasal dari organ dalam tubuh

eg. Lapar, haus, rasa sakit dalam

Propioseptor

Reseptor menerima rangsang/impuls berkaitan dengan bagian anggota gerakan tubuh

eg. Posisi dan pergerakan tubuhSlide4

INDERA PENGLIHATAN

Anatomi MATA

Terdiri atas

bulbus occuli

(bola mata), struktur pelindung :

cavum orbita

(rongga mata),

palpebrea

(kelopak mata),

conjunctiva

,

glandula lacrimalis

(kelenjar air mata), dan penggerak bola mata (otot ekstrinsik penggerak bola mata : 4 mm. rectus, 2 mm. Obliquus) → melekat jadi 1 dsb

capsula tenon

.

BOLA MATA

Bola mata mempunyai bentuk hampir “bulat” (D ± 23mm), dengan bagian anterior yang lebih cembung,disebut

cornea.

Pada kutub posterior, N II keluar menuju otak pada bagian medial dari axis bola mata, dimana fovea centralis yang merupakan titik tempat bayangan jatuh berada lebih lateral. Slide5

Dindingnya terdiri atas 3 lapisan Lapisan terluar (tunica fibrosa) → sclera & cornea

Lapisan tengah (tunica vasculosa) → choroid, corpus cilliaris, iris

Lapisan terdalam (tunica interna) → retina, sel epithel pigmen retina

Terbagi menjadi 2 ruangan yaitu COA (camera occuli anterior) dan COP (posterior) oleh iris.

Media refrakta → cornea, aquos humor, lensa, corpus vitreum

Apparatus akomodasi → lensa, zonula, otot cilliarisSlide6

ScleraThe sclera, which is white in adults, consists of packed lamellae of collagen fibers covering the

posterior 5

/6

of the eye. At the corneal

limbus

it

becomes the substantia propria corneae (stroma).

Cornea

The cornea has a diameter of about 12 mm in

adults. The outside of the cornea consists of

stratified nonkeratinized squamous epithelium,

which changes to the epithelium of the

bulbar conjunctiva at the corneal

limbus

. The

inside is formed by a single layer of flat

endothelialcells

.

The refractive power of the

cornea is about 42

diopters

(

Db). The central

thickness is approximately 500

μm

.

Lens

The lens, with a horizontal diameter of about

10 mm, is situated in the posterior chamber of

the eye. It is

about 3–4 mm thick at the center

.

It is a biconvex lens, with the

anterior surface

less curved than the posterior surface

. The lens

shell, which surrounds the nucleus

concentrically,lies

beneath the lens capsule.Slide7

Vitreous BodyThe vitreous body, which is 95 % water, fills the vitreous space situated behind the lens. Its gelatinous

consistency is due to the presence

ofhyaluronic

acid,

mucopolysaccharides

, and collagen

fibrils.

Choroid

The choroid occupies the major part of the middle

layer of the eye. In addition to arteries and

veins, it also carries

approximately 15–20

ciliary

nerves. It is separated from the retina by

Bruch’s membrane, which is 2

μm

thick.

Iris and Pupil

The iris, like a diaphragm, forms the

pupil.

The iris is

thinnest at the

margin of the pupil and allows

the

bilaminar

pigmented epithelium on the

back to be seen. The pupil is surrounded by the

sphincter pupillae muscle (parasympathetic

innervation

via the

oculomotor

nerve), the

innervation

of which produces contraction of the

pupil (

miosis

). At the margin of the pupil, the

iris is widely connected with the

ciliary

body.

The muscle fibers of the

dilatator

pupillae

muscle

(cervical sympathetic) run here, contraction

of which leads to pupil dilatation (

mydriasis

).

Slide8

RetinaThe retina forms the inner layer of the eye. Divided into a

nonsensory

(anterior)

part and an

opticpart

.

The macula

lutea

(yellow spot) is lateral to this with the

fovea

centralis

at its center

, the site of maximum visual

acuity.

The inner retina includes

the photoreceptor cells and nine further

identifiable layers of the cerebral layer

.

P

rimary

sensory epithelial cells

→

120 million rods

and

6–7 million

cones

.

There are

only cones in the

fovea

centralis

, with no other layers of the cerebral

layer.

Rods and cones constitute the retina’s receptors.

fovea

centralis

consists exclusively

of

cones, which are responsible for color

vision in good lighting (

photopic

vision

).

The

rods are responsible for vision in poor

light (

scotopic

vision

); their greatest density is

around the fovea

centralis

but they are also distributed

over

the entire retina

.

The photoreceptors

are absent in the region of the optic

disc → blind spotSlide9

Optic Nerve and Optic TractThe optic nerve is about 45 mm in length,

twothirds

of which is inside the orbit. At the lamina

cribrosa

1 million nerve fibers leave the

eyeball and from this point are surrounded by

a

medullary

sheath of

oligodenroglia

,

duramater

and

pia

mater.

After passing through the

optic canal, it reaches the

optic chiasm on the

floor of the third ventricle after running about

10 mm in the middle cranial

fossa

. Here the

nasal fibers of the retina cross to the opposite

side. The optic nerve fibers run as the

optic

tract as far as the lateral

geniculate

body.

The

optic radiation (Gratiolet’s radiating fibers)

runs from here through the posterior

crus

of

the internal capsule to the primary optic visual

cortex, the

area

striata

, area 17.Slide10

AccommodationAccommodation signifies the ability of the eye

to

focus the rays from objects to form a clear

image on the retinal plane in relation to the objects’

distance from the eye.

Accommodation is

based in particular on the ability of the elastic

lens to change from a more spherical shape

with high

converging power (near focus) to a

more elliptical shape with low converging

power (distant focus).

Visual acuity

means the resolving

ability of the eye with an optimally correcting

lens, i.e. the ability of the retina barely

to distinguish two points from one another

(resolution threshold). A normal eye can just

differentiate two points when the rays emerging

from them form an angle at the eye of one

minute of arc (1/60 degree).

Visual acuity is calculated

from the actual distance of the points

from the eye divided by the distance at which

the normal eye can resolve the points, and in

the normal eye it is therefore 1ßq = 1.0.

Optotypes

projected into the distanceSlide11

Visus sangat dipengaruhi oleh sifat fisis mata (aberasi mata = kegagalan memfokuskan bayangan tepat di fovea centralis), besarnya pupil, komposisi cahaya, kemampuan akomodasi, elastisitas otot, intensitas cahaya, faktor retina

V = d/DSlide12

AdaptationAdaptation (A) signifies the adjustment of the

eye to different light levels

. This is a complex

process, which comprises a change in pupil

size, a change between rod and cone vision, and

a change in the sensitivity of the retina.

According

to the

duplicity theory of vision, daytime

and color vision (

photopic

vision) is a

function of the cone apparatus, while vision in

dim light and night vision (

scotopic

vision) are

provided by the rod apparatus.

Light adaptation

means the transition to

photopic

vision

and is based on pupil constriction and the transition

from rod to cone vision with the breakdown

of rhodopsin.Slide13

GERAK BOLA MATA

N III → m rectus superior, m.rectus inferior, m. rectus medial,

m.obliquus inferior

N IV → m obliquus superior

N VI → m. rectus lateral Slide14

BUTA WARNAAKROMATISME/AKROMATOPSIA/Total → tidak dapat membedakan warna dasar, terlihat hitam dan abu-abu

DIAKROMATISME/Partial → bisa mbedakan warna tertentu

Deutrinophia : sel kerucut hijau (-)

Protanophia : sel kerucut merah (-)

Tritanophia : sel kerucut biru/kuning (-)

Menurut Hering ada 3 macam fotokhemis yang mempunyai 6 macam kualitas yang memberikan 6 macam sensasi → substansi putih-hitam, merah-hijau, biru-kuning.

Test Buta warna → Uji Holmgren, Uji Stiling-Isihara.Slide15

Mata manusia dapat mendeteksi hampir semua gradasi warna bila cahaya monokromatik merah, hijau dan biru dicampur secara tepat dalam berbagai kombinasi tergantung persentase campuran warna-warna dasar tersebut.Young & Helmholtz → Sel kerucut dapat menerima warna merah, hijau dan biru.

Ke tiga macam sel kerucut mengandung fotokhemis yang dapat diurai oleh sinar matahari, bila ketiga macam sel kerucut itu mendapat stimulus yang bersamaan maka akan terlihat warna putih. Warna-warna lain merupakan kombinasi dari ketiga macam warna dasar.

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Thank You!!!!!