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INSTITUTO DE LA VISION 07 marzo 2011 Dr. Fily Martinez D.

Anatomia retina

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Page 1: Anatomia retina

INSTITUTO DE LA VISION

07 marzo 2011

Dr. Fily Martinez D.

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RETINA:

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Retina: develops as part of the brain

Retina is 2 layers

Outer thin pigmented layer:

Melanocytes (prevent light scattering)

Inner thicker neural layer

Plays a direct role in vision

Three type of neurons:

1. (outer layer) Fibrous: dense connective tissue

Sclera – white of the eye

Cornea

2. (middle layer) Vascular: uvea

Choroid – posterior, pigmented

Ciliary body

Iris

3. (inner layer) Sensory

Retina and optic nerve

Remember

the 3 layers of

the external

eye?

1. Photoreceptors

2. Bipolor cells

3. Ganglion cells

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Light passes through pupil in iris, through vitreous humor, through axons, ganglion cells and bipolar cells, to photoreceptors next to pigmented layer

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Photoreceptor neurons signal bipolar cells, which signal ganglion cells to generate (or not) action potentials: axons run on internal surface to optic nerve which runs to brain

*Know that axons from the retina form the optic nerve, CN II

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Photoreceptors: 2 types

Rod cells

More sensitive to light - vision permitted in dim light but only gray and fuzzy

Only black and white and not sharp

Cone cells

High acuity in bright light

Color vision

3 sub-types: blue, red and green light cones

*Know that rods are for B & W and cones are for color

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If you want more detail, it’s fascinating…

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Retina through ophthalmoscope

Macula: at posterior pole

Fovea: maximal visual acuity (most concentrated cones)

Optic disc: optic nerve exits

Vessels

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Visual pathwaysGreen is area seen by both eyes, and is

the area of stereoscopic vision

At optic chiasm, medial fibers from each eye

(which view lateral fields of vision) cross to

opposite side. Optic tracts (of crossed and

uncrossed, sensing opposite side of visual field of

both eyes) synapse with neurons in lateral

geniculate of thalamus. These axons form the optic

radiation and terminate in the primary visual cortex

in the occipital lobe. Left half of visual field

perceived by right cerebral cortex, and vice versa.

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TIPOS CELULARES:

CEL. FOTORRECEPTORAS: CONOS Y BASTONES.

CEL. HORIZONTALES.

CEL. BIPOLARES.

CEL. AMACRINAS.

CEL. INTERPLEXIFORMES.

CEL. GANGLIONARES.

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CAPAS DE LA RETINA:1. EPR: CELULAS PIGMENTADAS.

2. CAPA DE FOTORRECEPTORES: CONOS Y BASTONES.

3. MLE: UNION INTERCEL. ENTRE CEL. FR Y CEL. DE MÜLLER.

4. CAPA NUC. EXT: FORMADA POR LOS NUCLEOS CELULARES DE LAS CEL. FOTORRECEPTORAS.

5. CAPA PLEXIFORME EXT: CONEXIÓN SINAPTICA DE CEL. FR, BIP Y HORIZ.

6. CAPA NUC. INTER: FORMADA POR NUC. DE LAS CEL. BIP, HORIZ. Y AMACRINAS.

7. CAPA PLEX. INTER: CONEXIÓN SINAPTICA ENTRE CEL. BIP, AMACRINAS Y GANGLIONARES.

8. CAPA DE CEL. GANGLIONARES.

9. CAPA DE FIBRAS NERVIOSAS.

10. MLI: LAMINA BASAL QUE SEPARA LAS CEL. DE MÜLLER.

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RETINA: EPR

•ES UNA MONOCAPA DE CELULAS QUE CONTIENEN MELANOSOMAS.

•TEJIDO VITAL PARA EL MANTENIMIENTO DE LA FUNCION FOTORRECEPTORA.

•UNO DE LOS TEJIDOS CON MAYOR ACTIVIDAD METABOLICA.

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FUNCIONES DEL EPR:

•REGULACION DE LA TEMPERATURA

•MANTENIMIENTO DE LA BARRERAHEMATORRETINIANA EXTERNA

•ADHESION RETINIANA

•ABSORCION DE LA LUZ

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FUNCIONES DEL EPR:

• FAGOCITOSIS DE LOS SEGMENTOS DESPRENDIDOS DE LOS FOTORRECEPTORES

• APORTE DE O2 Y NUTRIENTES A FOTORRECEPTORES

• TRANSP. ACTIVO DE MAT. DENTRO Y FUERA

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RETINA: ELEMENTOS VASCULARES

CIRCULACION COROIDEA RETINA EXT.

ART. RETINIANA CENTRAL RETINA INT.

CIRCULAC. MACULAR ART. CILIORETINAL

VASOS SANGUINEOS RETINIANOS MANTIEN LA BARRERA HEMATORRETINIANA INTERNA

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Thank you. Retina

Service.