Exam 3: Eye Flashcards
Palpebrae
-eyelids
External Landmark: Sclera
-whites of the eye
External Landmark: Cornea
-transparent center part in front of the iris
External Landmark: Iris
-pigmented part of eye
External Landmark: Pupil
-opening of iris
Conjunctiva
- lines sclera and eyelid
- function: secretes mucus as a lubricant
Conjuctivitis
- pink eye
- imflamed conjunctiva
Lacrimal Apparatus (function, structures, contents)
- produces/collects tears (lacrimal fluid)
- consists of lacrimal gland, lacrimal canaliculi, lacrimal puncti, and nasolacrimal duct
- contains water, sodium ions, antibodies (fight infections, lysozyme-antibacterial agent)
Lacrimal Gland
-produces and secretes tears
Lacrimal Canaliculi
- from lacrimal puncti to nasal lacrimal duct
- drain tears
Nasolacrimal Duct
- internal
- drains tears into nasal cavity, where they are eventually swallowed
Why do you get a runny nose when you cry?
-overproduction of tears overflows system
Medial Recuts
-moves eye medially (adducts)
Lateral Rectus
-moves eye laterally (abducts)
Superior Rectus
-elevates and moves eye medially (adducts)
Inferior Rectus
-depresses and moves eye medially (adducts)
Superior Oblique
- depresses (pupil moves inferiorly) and moves eye laterally
- attaches to superior posterior part of eye
Inferior Oblique
- elevates (pupil moves superiorly) and moves eye laterally
- attaches to inferior posterior part of eye
Website to help learn eye movements
anatomy.hsc.wvu.edu/ReillyDental/VirtualPatients/ExtraocularSkeletalMuscle.swf
Lens
- biconvex, transparent structure inside eyeball
- function: refracts light rays
- held in place by suspensory ligaments
Suspensory Ligaments
-actually change shape of lens due to what type of vision
How?
-when taut, make lens fatter for far vision
-when looser, make lens ‘puffier’ for near vision
Fibrous Tunic
- avascular
- made up of sclera and cornea
Sclera (Function)
-supports and maintains eye shape
Cornea (Structure)
-curved transparent structure anterior to iris and pupil
Vascular Tunic
- contains blood vessels to nourish eye
- consists of choroid, cilliary body, and iris (listed posterior to anterior)
Choroid
- dark brown membrane
- function: refracts light rays
Cillary Body
- ring of smooth muscle tissue that surrounds the lens
- attaches to lens via suspensory ligaments
- functions: changes pull on suspensory ligaments and secretes aqueous humor
- far vision: cilliary relaxes, suspensory tight
- near vision: cillary contract, suspensory loose
Aqueous Humor
- fluid very similar to CSF in composition and function
- brings nutrients in and removes waste
- drains into dural venous sinuses
Iris
- pigmented colored part of eye
- contains pupil
- function: constricts or dilates pupil to regulate amount of light entering eye
Retina
- converts light rays to nerve impulses
- consists of pigmented layer and neural layer
Pigmented Layer
- outer layer of retina adjacent to choroid
- function: absorb stray light rays
Neural Layer
- inner layer of retina
- function: its photoreceptors receive light information and convert it into nerve impulses that are sent, via CN II (optic nerve) to the brain
- 2 types: rods and cones
Rods
- work in dim/low light
- image fuzzy not very sharp
Cones
- work in bright light, produce clear, sharp image
- perceive color
Glaucoma
- buildup of pressure in space containing aqueous humor
- 1 cause: increased pressure in space-not draining properly (too much aqueous humor)
- can cause blindess
Optic Disc (Blind Spot)
- area where the optic nerve exists the eye
- contains no photoreceptors-only axons
Macula Lutea
- lateral to optic disc
- in center is Fovea Centralis
Fovea Centralis
- area of sharpest vision
- only cones (so needs light)
Anterior Cavity
- between cornea and lens
- filled with aqueous humor
Posterior Cavity
- between lens and retina
- contains vitreous humor
Vitreous umor
- gelatinous-helps maintain shape of eye
- not constantly made
- have same amount since birth
Pathway of Processing Visual Information
- light rays enter eye through cornea and are refracted
- light rays are further refracted by lens
- light rays focus on retina
- light ray information is converted to nerve impulses by photoreceptors
- nerve impulses transmitted to the brain via CN II (Optic Nerve)
LASIK Eye Surgery
-reshape cornea with laser