Transcript Psikologi faal - matrissya hermita

Matrissya Hermita
PSIKOLOGI FAAL
INDERA PENGLIHATAN 1 & 2
RESEPTOR dan PENGINDERAAN
Reseptor : 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, meissner
Interoseptor
Reseptor yang menerima rangsang/impuls yang
berkaitan/berasal dari organ dalam tubuh
eg. Lapar, haus, rasa sakit dalam
Propioseptor
Reseptor menerima rangsang/impuls
dengan bagian anggota gerakan tubuh
eg. Posisi dan pergerakan tubuh
berkaitan
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.
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 cilliaris
Sclera
The 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.
Vitreous Body
The 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).
Retina
The 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.
Primary 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 spot
Optic Nerve and Optic Tract
The 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.
Accommodation
Accommodation 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 distance
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/D
Adaptation
Adaptation (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.
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
BUTA WARNA
AKROMATISME/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.
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.