Transcript HISTOLOGY OF EYE

Dr Iram Tassaduq
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Stratified squamous
non keratinized
Consist of 5-6 layer
Active mitosis
Turnover time for
cells is 6-7 days
Extremely sensitive
to touch
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Consists of collagen
fibers
Acellular clear
membrane lie under the
epithelium
Cannot be regenerated
if destroyed
Provides strength to
cornea
Acts as a barrier against
spread of infections
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Many layers of
collagen bundles
run parallel to each
other and parallel
to the surface of the
cornea making the
cornea transparent,
Avascular structure
Nuclei of
fibroblasts
90% of corneal
thickness
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Fine collagenous
filaments
5-10 micrometer
thick
Regenerates
quickly
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Single layer of flat
hexagonal cells with
no mitosis
Pumps water out
Prevent corneal
edema opacification
Maintain corneal
transparency
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Capsule
Refractile and formed of
type IV collagen
Sub capsular epithelium
Single layer of cuboidal
epithelium present on
anterior surface
Lens fibers
Highly differentiated
cells.
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Form the body of the lens.
located deep to the
subcapsular epithelium.
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Nucleated in the soft, outer
cortex of the lens. As new
lens fibers are added to the
periphery of the cortex, lens
fibers located deeper in the
cortex loose their nuclei .
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Cytoplasm filled with
crystalline proteins. These
proteins are responsible for
the transparency .
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Innermost layer of eye ball
Develops from double walled optic cup
Outer layer forms pigment epithelium
Inner layer forms neural retina
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The retina is the site of sensory transduction
The retina is nervous tissue composed of 6
major types of neurons and one special type of
glial-like cell (the Muller cell)
The organization of the retina is based on a
three neuron chain (photoreceptor cell to
bipolar cell to ganglion cell)
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RODS
 Thin elongated cells
 Composed of inner and outer segments
 120 million photoreceptor cells called rods
(responsible for peripheral and dim light vision)
 Contain rhodopsin
CONES
 Lesser in number than rods
 Responsible for providing central, bright light,
fine detail, and color vision
 Contain visual pigment
iodopsin
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Horizontal cells interconnect groups of
photoreceptor cells
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Bipolar cells - interconnect
photoreceptor cells with
ganglion cells
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Amacrine cells interconnect
groups of ganglion cells and
bipolar cells
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Ganglion cells possess
long axons that extend
through the nerve fiber layer
of the retina and then come
together to form the optic
nerve
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Pigment epithelium
The layer of rods and cones
External limiting membrane.
The outer nuclear layer
Outer plexiform layer
Inner nuclear layer.
The internal plexiform layer
Ganglion cell layer.
Layer of optic nerve fibers
The internal limiting membrane
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Consist of columnar
cells
Absorbs light
Synthesizes melanin
granules
Vitamin A
metabolism
Cells have phagocytic
properties
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Not a true membrane
Formed of row of
zonula adherens
between muller cells
and rods and cones
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Formed by the
processes of
photoreceptor cells
and retinal neuronal
cells that is horizontal,
bipolar and amacrine
cells
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Consist of nuclei
of bipolar,
amacrine,
horizontal and
muller cells
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Formed of complex
intermingled nerve
cell processes
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Consist of cell bodies
of large multipolar
neurons
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Consist of axons of
ganglion cells