Medical Retina Flashcards
(157 cards)
What is the vitreous cavity in the retina?
LARGEST CAVITY 4.0-4.4 ML IN ADULTHOOD
CONTAINS VISCOELASTIC GEL MADE OF MOSTLY WATER
CONTAINS MAINLY HYALURONIC ACID AND TYPE II COLLAGEN
What is the vitreous derived from?
Embryologically from the diencephalon
What does the diencephalon give rise to?
Optic vesicle and then optic cup
What are the two layers of the retina?
Retinal Pigment Epithelial Layers
Neurosensory Retina
Why does retinal detachment occur?
weak connection between RPE and NSR
What are the 9 layers of the retinal pigment epithelium? (Internal to external)
- Internal limiting membrane
- Nerve fibre Layers
- Ganglion cell layer
- Inner plexiform layer
- Inner nuclear layers
- Outer plexiform layer
- Outer nuclear layer
- External limiting membrane
- Photoreceptor layer
What is the function of the internal limiting membrane?
SEPARATES THE RETINA FROM THE VITREOUS
What is the function of the nerve fibre layer?
CONTAINS GANGLION CELL AXONS THAT COME TOGETHER TO FORM THE OPTIC NERVE,
PRESENT IN THE MACULAR AREA AND TRAVELS NASALLY TO THE OPTIC NERVE DIRECTLY THROUGH THE PAPILLOMACULAR BUNDLE
What is the function of the ganglion cells layer?
CONTAINS THE CELL BODIES OF THE GANGLION CELLS, INVOLVED IN TRANSMITTING VISUAL INFORMATION TO THE BRAIN INCLUDING STIMULUS REQUIRES FOR LIGHT PUPILLARY RESPONSE
What is the function of the inner plexiform layer?
SYNAPTIC LAYER BETWEEN SECOND AND THIRD ORDER NEURONS
What is the function of the inner nuclear layer?
CONTAINS CELL BODIES OF BIPOLAR CELLS AND CELL BODIES OF MULLER CELLS
What is the function of the outer plexiform layer?
SYNAPTIC LAYER BETWEEN PHOTORECEPTORS AND BIPOLAR CELLS
What is the function of the outer nuclear layer?
CONTAINS CELL BODIES OF RODS AND CONES
What is the function of the external limiting membrane?
CONNECTIONS BETWEEN PHOTORECEPTORS AND MULLER CELLS CREATE THE ELM
What is the function of the photoreceptor layer?
contains rods and cones
What is the RPE composed of?
SINGLE LAYER OF A CUBOIDAL EPITHELIAL CELLS CONTAINING MELANOSOMES AND HAS MANY FUNCTIONS
What are the functions of the RPE?
ABROBS LIGHTS AND PREVENTS THE SCATTERING OF LIGHT WITHIN THE EYE
REPLENSIHES THE MOLECULES NEEDED FOR PHOTOTRANSDUCTION
CONTAINS A BLOOD RETINAL BARRIER WHICH PROVIDES A SELECTIVELY PERMEABLE MEMBRANE TO SUPPLY NUTRIENTS TO THE PHOTORECEPTORS AND MAINTAIN HOMEOSTASIS
-BLOOD RETINAL BARRIER IS MAINTAINED BY THE ZONULAE OCCLUDENTES
PHAGOCYTOSIS OF PHOTORECEPTOR OUTER SEGMENT MEMBRANES
TRANSPORT AND STORAGE OF METABOLITES AND VITAMINS
What is the macula lutea?
MACULA IS PIGMENTED, ROUNDED AREA AT THE POSTERIOR POLE OF THE RETINA, LOCATED TEMPORAL TO THE OPTIC DISC
What is the macula lutea made of?
SEVERAL LAYERS OF GANGLION CELLS (peripheral retinal only has one layer of ganglion cells)
What is the fovea?
DEPRESSION AT THE CENTRE OF THE MACULA THAT CONTAINS ONLY CONES AND REPRESENTS THE RETINA’S HIGHEST VISUAL ACUITY
What is unique about the centre of the fovea?
CENTRE OF THE FOVEA IS AVASCULAR AND IS DEPENDENT ON THE UNDERLYING CHORIOCAPILLARIS FOR BLOOD SUPPLY VIA DIFFUSION
How many rods are there?
120 million
How many cones are there?
6 million
What is the pigment in rods?
rhodopsin