3 layers 1. Outer layer (CT layer) = Tunica Fibrosa - Sclera = CT - Conea 2. Uvea - Choroid - vascular layer which provides nutrients to the retina - ciliary body - Iris 3. Retina (innermost part) - consists of rods and cones and neruons that will become the optic nerve - mainly nerual (5/6) - non neural retina lines the ciliary body and the iris

- outermost layer - fibrous layer - Sclera - covers most of the back of the eye - Cornea - in contact with air on one side and fluid on the other

- CT layer - acting as a capsule to hold the eye in place - has typical CT materials - fibroblasts, amorphous components, etc.

- Has 5 layers 1. corneal epithelium (outermost layer) 2. Bowman's membrane - thick layer of extracellular material - noncellular 3. Stromal layer - thickest layer 4. Descemel's membrane 5. Endothelium Layer - squamous Light must pass through all 5 layers of cornea before it gets inot the anterior chamber

- Facilitates equilibrium of pressure within the eye - Equilibrates the pressure in the anterior chamber - if you have pressure that builds up in the anterior chamber, it can drain out through this canal

3 layers 1. choroid - vascular 2. ciliary body 3. iris

- Blood vessels providing nutrients to the sclera (CT) and the retina Choriocapillary layer - close to the retina - subdivision of choroid - blood vessels are much smaller - filled with capillaries - immediately adjacent to the retina

- contain muscle that can contract and change shape of lens for visual accommodation - folds of epithelium = ciliary processes - from the processes, you have zonule fibers - by changing the shape of the muscle, you will pull or relax on the lens to change its shape for visual acuity

- Contain a double layer of low columnar to cuboidal epithelium - Inner layer is pigmented with melanin granules - outer layer is non pigmented

- Double layer of epithelium continues from the ciliary processes to line the posterior iris - eye color is due to amount of pigment in the epithelium

- from the ciliary processes, you get zonule fibers attached to the lens - oxytalin fibers - first component of elastic fibers - bridge between ciliary body and lens - Pull on the lens - change lens shape

- like a sponge - a lot of hyaluronic acid - - glycosaminoglycans - hyrophobic - absorb a lot of water - -holds a lot of water

- Transition form the neural retina to the non neural retina - non neural is double layer epithelium that lines the ciliary body and back of the iris

- most sensitive to light - only give you black, white and shades of grey - Rhodopsin - responsible for perceptions of black, white and grey - under low light conditions, the rods are able to pick up light that the cones cannot

Eye and Ear Flashcards by Aaron Kesinger

Structure of the eye

3 layers

Outer layer (CT layer) = Tunica Fibrosa
- Sclera = CT
- Conea
Uvea
- Choroid - vascular layer which provides nutrients to the retina
- ciliary body
- Iris
Retina (innermost part)
- consists of rods and cones and neruons that will become the optic nerve
- mainly nerual (5/6)
- non neural retina lines the ciliary body and the iris

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Tunica Fibrosa

outermost layer
fibrous layer
Sclera - covers most of the back of the eye
Cornea - in contact with air on one side and fluid on the other

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Sclera

CT layer
acting as a capsule to hold the eye in place
has typical CT materials - fibroblasts, amorphous components, etc.

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Cornea

Has 5 layers
1. corneal epithelium (outermost layer)

Bowman’s membrane
- thick layer of extracellular material
- noncellular
Stromal layer
- thickest layer
Descemel’s membrane
Endothelium Layer
- squamous

Light must pass through all 5 layers of cornea before it gets inot the anterior chamber

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Canal of Schlemn

Facilitates equilibrium of pressure within the eye
Equilibrates the pressure in the anterior chamber
if you have pressure that builds up in the anterior chamber, it can drain out through this canal

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Uvea

3 layers

choroid - vascular
ciliary body
iris

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Choroid

Blood vessels providing nutrients to the sclera (CT) and the retina

Choriocapillary layer - close to the retina

subdivision of choroid
blood vessels are much smaller - filled with capillaries
immediately adjacent to the retina

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Ciliary Body

contain muscle that can contract and change shape of lens for visual accommodation
folds of epithelium = ciliary processes
from the processes, you have zonule fibers
by changing the shape of the muscle, you will pull or relax on the lens to change its shape for visual acuity

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Ciliary Processes

Contain a double layer of low columnar to cuboidal epithelium
Inner layer is pigmented with melanin granules
outer layer is non pigmented

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Iris

Double layer of epithelium continues from the ciliary processes to line the posterior iris
eye color is due to amount of pigment in the epithelium

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Zonule Fibers

from the ciliary processes, you get zonule fibers attached to the lens
oxytalin fibers - first component of elastic fibers
bridge between ciliary body and lens
Pull on the lens - change lens shape

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Vitreous Chamber

like a sponge
a lot of hyaluronic acid
- glycosaminoglycans - hyrophobic - absorb a lot of water
-holds a lot of water

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Retina

5/6 of the back of the eye ball is neural retina

forward 1/6 is non neural
- double layer epithelium that projects forward to line the ciliary body and iris

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3 Layers of the Retina

Outer most/ deepest layer
- consists of rods and cones embedded in pigmented epithelium
- receive photons of energy in the form of light
- stimulate some visual stimulus
Bipolar neurons
- one side on the rods and cones
- the other on a ganglian cell
- Muller cell - sustantacular cell (support cell)
Ganglain Cell layer
- one end attaches to the bipolar neuron layer
- the other end forms axons and project to become the optic nerve

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Ora serrata

Transition form the neural retina to the non neural retina

- non neural is double layer epithelium that lines the ciliary body and back of the iris

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Rods

most sensitive to light
only give you black, white and shades of grey
Rhodopsin - responsible for perceptions of black, white and grey
under low light conditions, the rods are able to pick up light that the cones cannot

Cones

give you color vision
have iodopsin - gives perceptions of color
cones need a good bit of light to be stimulated
in the light they are able to pick up more photons of light

Fobea Centralis

macula
only cones
located at the back of the eyeball
responsible for central vision and visual acuity

Optic Nerve

blind spot
central artery of the retina runs through the optic nerve
no rods or cones

Lens

outermost layer is lens capsule - CT, non cellular
lens epithelium - simple cuboidal to columnar
Differentiating lens fibers
mature lens fibers
light has to go through all of these layers plus the anterior chamber before reaching the rods and cones

Eyelid

Innermost layer is the conjunctiva

in contact with the eye ball
layer of epithelial cells

Tarsal plate gives rigidity to the eye
- so you can move your eye

Meibomian Gland
- sebaceous glands

Orbicular Muscle
- contract to allow movement of the eye

Eyelashes
- prevents things from getting in the eye

Conjunctiva

Layer in contact with part of the eyeball

- predominantly stratified columnar to stratified squamous

Lacrimal Apparatus

Lacrimal Gland

produces tears
secretes fluid onto the eye

Extraocular Muscles

Pull on the eye to that it can move around and to focus

Structure of the Ear

3 Layers 1. Outer ear - eardrum 2. Middle ear - articulating bones - create a sound wave for inner ear 3. Inner ear - cochlea (hearing) - vestibular apparatus (balance and motion)

Pinna

- Contains a lot of CT and elastic fibers

External Auditory Meatus

- ear canal - lined by epidermis - Continuous with the ear lobe - contains the ceruminous glands - gives rise to ear wax

Tympanum

- Tympanic membrane (eardrum) - 3 layers 1. Epidermis continuous with the canal 2. middle layer of fibrous CT 3. Inner layer of simple cuboidal and/or squamous

Middle Ear

Malleus, incus, and stapes - articulating bones - transmit a sound wave from eardrum to the oval window - when they articulate, they amplify the signal of sound - stapes has a pad that pounds on the oval window of the inner ear

Bony and Membranous Labyrinth

Bony Labyrinth - bone "shell" around the membranous labyrinth Membranous labyrinth - the tissue within the bony labyrinth - nerves are quite large and attach to the three components of the inner ear

Inner Ear Sensory Regions

Vestibular Apparatus - utricle and the saccule - maculae is the sensory structure within - responsible for the perception of motion Semicircular canals - 3 of them in different orientations (x,y,z) - cristae ampullares - responsible for 3D orientaion and motion Cochlea - Oran of Corti - responsible for hearing

Cochlea

- sea shell shaped - Oval window is being baned on by the stapes - pressure wave passes down through cochlea - causes the organ of Corti to vibrate, causing sensation of sound - pressure goes back down and pushes on the round window - vibration of the tectorial membrane is responsible for stimulating the hair cells of the of the organ of corti

Middle Duct of Cochlea

- called scala media - organ of corti is on the scala media - one the back of the scala media, there is a layer of cells called the scala vascularis - secrete endolymph (maintains the viability of the cells of the organ of corti) - surrounded by vesibular membrane

Organ of Corti

- As the fluid within the canal is pushed by a pressure wave the tectorial membrane rubs against the hair cells - vibrating due to sound creating a pressure wave - the hair cells perceive the movement of tectorial membrane - projects that on the cochlear nerve which then goes to the auditory nerve which is how you hear

Stereocilia Bundles

- Hair cells - in a v shaped row | - Tectorial membrane rubbing on the hair cells transduces a signal perceived as sound

Vestibular Apparatus

- within the utricle and the saccule there is a sensory structure called the macula

Macula

- contains stereocilia and one long true cilia - embedded in a gelatinous layer - has calcium carbonate crystals on top of it - otoliths or otoconia - otoliths provide for inertia - cilia and stereocilia bend with the movement of the gelatinous layer which provides for perception of linear acceleration - sensory cells containing stereocilia and one true cilia at the end of the escalating ramped up bundle of stereocilia

Cristae Ampullares

- at the base of semicircular canals perceive rotation - The gelatinous layer rubs against the other side of the canal - inertia is provided by the rubbing against the other side of the canal

Semicircular canals

- canals are in X, Y, Z orientation allowing for perception of rotation