-Conjunctiva is thin/transparent/tough to allow light to pass through/to protect the eye.
-Sclerotic layer is made up of (collagen) fibers/fibrous. It maintains shape of the eyeball/protects the eye.
-Cornea is transparent/curved thus refracts light rays/allows light to pass through.
-Choroid is a layer of tissue with black pigment/dark pigment. Prevents internal reflection of light in the eye/contains blood vessels that supply oxygen/nutrients/remove (metabolic) wastes from the eye.
-Retina has cones/rods for bright colour vision/low light vision.
-Yellow spot has a high concentration of cones for accurate vision/visual acuity.
-Blind spot has no cones and rods. Place where optic nerve leaves/enters the eye optic nerve has (sensory) nerve fibers for transmission of impulses to the brain (for interpretation).
-Lens is biconvex/made up of elastic material/transparent. Adjust focus on far or near objects allow light to pass through/for refraction of light rays.
-Ciliary body is made up of muscle fibers glandular which contract/relax to change shape.
-Suspensory ligaments are inelastic to hold lens in position/attach it to ciliary body.
-Iris(is the coloured part of the eye it) has radial and circular muscles which control size of pupil.
-Pupil is the small hole at the centre of iris through which light passes into the eye.
-Aqueous humor is a fluid through which oxygen/nutrients pass to the cornea/lens/maintains shape of the eyeball/refracts light rays.
-Vitreous humor is a fluid which maintains shape of eye/refracts light rays.
OR
How is the human eyeball adapted to its function?
Sclera/sclerotic layer; white fibrous layer; made up of thick connective tissue; protects the eye; maintains shape of eyeball; Cornea; transparent; disc-shaped layer; that allows light to enter the eye; refracts light towards the retina; Conjunctiva; delicate membrane; lining the inside of the eyelid; protects the cornea/eye; Eyelids and eye lashes; thin muscle with hairs; protects the cornea/eye from mechanical/chemical damage/protects the eye from entry of foreign particles; protects retina from bright light; Choroid; dark pigmented and membranous layer; that prevents light reflection within the eye/absorbs light; to prevent distortion of the image; has blood vessels; that nourish eye/retina/supply oxygen/remove carbon (IV) oxide and wastes; extends to form the ciliary body and iris; Ciliary muscles; have elastic muscles that contract and relax; to alter shape/curvature of lens during accommodation; Ciliary body; thickened front edge of the choroids layer; that produces aqueous humour; Suspensory ligaments; made up of elastic connective tissue whose contraction and relaxation helps to adjust the shape of lens during accommodation/holds lens in position; Lens; transparent; biconvex; balloon-like; it refracts light rays/focus light onto the retina; Vitreous humour; nourishes cornea/lens; refraction of light; maintains eyeball shape; Iris; thin circular ring; with circular and radial muscles; it gives eye colour/absorbs light; controls the amount of light entering the eye/adjusts size of pupil; Pupil; an aperture through which light enters the eye; Retina; has photoreceptor cells/rods/cones for image formation; generates impulses to the brain for interpretation; Fovea/Yellow spot; with only cones; for high visual acuity/most sensitive part of the retina Blind spot; point where nerve fibres emerge from the optic nerve/where optic nerve leaves eye/point where nerve fibres and blood vessels enter the eye; Optic nerve; transmits impulses to the brain; Muscles; inferior and superior oblique muscles; move eye from left to right; superior and inferior rectus muscles; move the eye up and down; external and internal rectus muscles steady the eye in its up and down movement; Tear/Lachrymal glands; secrete a watery and saline fluid containing lysozymes/lytic enzymes/is antiseptic (tears); that moisten the conjunctiva and cornea; washes away dust and other foreign objects; kills microorganisms entering the eye.
Anganifelix answered the question on April 18, 2018 at 11:08
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