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32 Cards in this Set

  • Front
  • Back

Eye and Vision

1. 70% of all Sensory receptors are in the eye


2. Almost half of Cerebral Cortex is involved in processing visual information


3. Most of eye is protected by fat and bony orbit

Structures of Eye

Protect eye and aid function


1. Eyebrows


2. Eyelids (superior/inferior palpebrae)


3. Conjunctiva (mucous)


4. Lacrimal apparatus (tears)


5. Extrinsic eye muscle


6. Commisures (corners of eye)

Eyebrows

1. Shades eye


2. Prevents sweat from reaching eye

Eyelids

1. Protects eye


2. Palpebral fissure (white space that separates Eyelids)


3. Lacrimal caruncle (elevation at medial Commisure. Contains oil and sweat glands)

Eyelids

1. Tarsal Plates (internal supporting conn. tissue sheet


2. Levator palpebrae (allows blinking by moving upper eyelid)


3. Eyelashes (Nerve endings of follicles initiate blinking reflex)

Eyelids (Lubricating glands)

1. Tarsal (Meibomian) glands (keeps eye moist)


2. Sebaceous glands (conditions follicles)


3. Ciliary glands (conditions follicles)

Conjunctiva

Transparent membrane that produces Lubricating mucous secretion


1. Palpebral Conjunctiva lines eyelid


2. Bulbar Conjunctiva covers white of eye


3. Conjunctivitis (pink eye)

Lacrimal Apparatus

Lacrimal gland/ducts connect to nasal cavity



Lacrimal secretion


1. Releases saline solution (tears)


2. Blinking spreads tears toward medial Commisure


3. Tears enter paired Lacrimal canaliculi via Lacrimal puncta


4. Drain into nasolacrimal duct

Extrinsic Eye Muscles

Extrinsic (origin is outside of eye)



1. 6 strap like muscles


2. Originate from bony orbit


3. Maintain shape of eye

Extrinsic Eye Muscles (Cont.)

4 rectus that originate from the common tendinous ring

Structure of Eyeball

1. Tunics (layers)


*Fibrous, Vascular, Sensory*


2. Humor (internal cavities filled with fluids



Lens separates internal cavity into anterior and posterior cavities

Fibrous Layer

Outermost layer. Dense avascular conn. tissue



1. Sclera/Cornea


2. Sclera (white of eye, opaque, protects/shapes eyeball, and anchors extrinsic eye muscles)

Fibrous Layer (Cont.)

1. Cornea (Transparent 1/6 of fibrous layer. Bends light as it enters the eye)


Fibrous Layer (Cont.)

1. Cornea (pain receptors for blinking/tearing)



Repairs extremely fast

Vascular Layer

Middle pigmented layers



1. Choroid, Ciliary Body, and Iris


2. Choroid (supplies blood to all layers. Has light absorbing brown pigment)


Vascular Layer (Cont.)

Ciliary Body



1. Ring of tissue surrounding lens that control shape (Ciliary Muscles)


2. Capillaries of processes secrete fluid


3. Ciliary zonule (suspensory ligament) holds lens in place

Vascular Layer (Cont.)

Iris



1. Colored part of eye (pupil is opening)


2. Sphincter pupillae (close vision and bright light)


3. Dilator pupillae (distant vision and dim light)

Sensory Layer

Pigmented Layer (1 row of cells)



1. Outer layer


2. Absorbs light


3. Stores vitamin A


4. Maintains rods/cones and Phagocytize debris

Sensory Layer

Neural Layer



1. Photoreceptors (rods and cones that transduce light energy

Retina

Ganglion Cell Axons



1. Run along inner surface of retina


2. Leave the eye as optic nerve

Photoreceptors

Rods (more abundant)



1. Dim light


2. Indistinct, fuzzy, non color Peripheral vision


3. Visual discs with rhodopsin (visual purple pigment, need vitamin A to make)

Photoreceptors (Cont.)

Cones



1. Bright light


2. Sharp, color vision


3. Visual discs with red, green, and blue pigments

Retina

Macula Lutea (yellow circular area)


Fovea Centralis (greatest concentration of cones)

Blood Supply to Retina

2 sources



1. Choroid (Outer third, Photoreceptors)


2. Central artery and veins (supply inner 2 thirds

Internal Chambers/Fluids

Anterior cavities contain aqueous humor



1. Plasma fluid filtered from capillaries of Ciliary processes


2. Supplied nutrients and oxygen to lens, Cornea, and Retina

Internal Chambers/Fluids

Glaucoma is compression of retina and optic nerve due to blockage of drainage of aqueous humor

Posterior Segment

Vitreous humor



1. Formed during embryonic development


2. Holds Retina in place

Lens

1. Binconvex, transparent, flexible, elastic, and avascular


2. Allows precise focusing of light on the Retina

Lens

1. Cells of lens epithelium turn into lens fibers that form the bulk of the lens


2. Lens fibers are cells filled with the transparent protein crystallin

Lens

1. Lens become denser, convex, and less elastic with age


2. Cataracts (clouding of lens, light doesn't get back to retina)

Visual Pathway

1. Axons of retinal Ganglion cells form the optic nerve


2. Fibers of the optic nerve decussate at the optic chiasma

Depth Perception

1. Both eyes view the same image from slightly different angels


2. Depth Perception (3-D) is from overlapping images