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Eyes
hihihi
| Term | Definition |
|---|---|
| Eyebrows | Keeps sweat out and communication through expression |
| Eyelashes | Initiate blinking and keep stuff out of eye |
| Eyelids (palpebrae) | Cartilage ring seal ring and clean and moisturize eye |
| Conjunctiva | Lining on inside of the inside of the eyelid for lubrication |
| Lacrimal apparatus | Sac and drain into nose |
| extrinsic eye muscles | enabling precise, coordinated eye movements (elevation, depression, rotation, side-to-side) and binocular vision 70% of all sensory receptors and 50% of brain processing about vision |
| Sclera | White of the eye, protects and shapes eyeball, apart of fibrous layer |
| Cornea | Transparent, nerve endings, which are most exposed and aid in light bending. Performs the initial refraction onto the lens |
| Choroid | Dark brown/black membrane, contains blood vessels, and helps absorb light prior to opening. |
| Ciliary body | Controls lens shape |
| Ciliary zonule or suspensory ligament | Holds lens in place |
| Iris | Colored flat donut between cornea and lens, contains sphincter papillae ( circular muscle) and (dialator pupillae) regulate the amount of light reaching the retina by controlling the diameter and size of the pupil |
| Pupil Constriction | (Miosis): In bright light + close , the circular sphincter pupillae muscle in the iris contracts, reducing the pupil size to protect the retina from excessive light. This is mediated by the parasympathetic nervous system. |
| Pupil Dilation | In dim light +distant , the radial dilator pupillae muscle of the iris contracts, enlarging the pupil to allow more light to enter. This is mediated by the sympathetic nervous system. |
| Pupil | regulates the amount of light entering the eye to enable vision |
| Retina | Contains photoreceptors that convert light energy, two layers pigments and neural layer |
| Outer pigment | next to choroid and extends which prevents light from scattering and contains photoreceptors along with vitamin A |
| Neural | Transparent with inner neural and extends anteriorly and posterior margin of ciliary body which the junction is called ora serratz. Optic disc where optic nerve exits |
| Rods | dim lights and peripheral visions receptors, and not sharp or in color. As retina extends peripherally, cone density declines. |
| Cones | In contrast are our vision receptors for bright light and high resolution color vision |
| Central vein and artery found in retina | leave thru optic nerve |
| Posterior segment | filled with vitreous humor , which binds water, transmits light, supports lens, hold neural retina against pigments layers, intraocular pressure, and counteracts extrinsic eye muscles |
| Anterior segment | Aqueous humor, drains continuously, supplies nutrients to lens and cornea |
| Lens | Thick and adjusts light into retina |
| Eyes respond to visible light | 400-700 nm, pockets of energy (photons) |
| Blue cones | 420 |
| Rods | 500 nm |
| Green cones | 530 nm |
| Red | 560 nm |
| Focusing Light | light, air, eye, goes thru cornea, aqueous humor, lens, and vitreous, neural layer of retina, pigmented |
| Bending. of light | Cornea is refractory agent and is constant while lens can change and allow for fine focusing and best adapted for distant. |
| Eyes are best adapted for distant -> fovea centralis | occurs when the eye's ciliary muscles relax, allowing the suspensory ligaments to pull the lens into a thinner, flatter shape. This reduces the refractive power, focusing distant light rays directly onto the retina. |
| Close vision focusing | Accommodation Process: When shifting focus to a near object, ciliary muscles contract to make the lens more curved, shortening the focal length. constriction Convergence: As the eyes focus on a close object, they must also turn inward (converge) together |
| Light adaptation | dark to light (constriction) cons |
| Dark adaptation | Light to dark (dilation) rods |
| Depth perception | see in 3d |
Created by:
nuhaSalim