The eye

• The eye is a sense organ containing receptors.
• Mammals and birds both have non-compound, refractive eyes.
• Eyes are sense organs that contain photoreceptors which can detect light.
• Light enters the eye through the pupil and hits photoreceptors on the retina at the back of the eye.
• The image on the retina is upside down but your brain flips it the right way up.
• The layers of the eye from the back are the Sclera, Choroid, and Retina.
• The optic disc is where the optic nerve meets the retina, a blind spot where there are no photoreceptors.
• Vitreous Humour is a transparent jelly-like liquid that gives the eyeball its shape and contains no blood vessels.
• The retina is a layer of light-sensitive cells (photoreceptors) at the back of the eye.
• The retina contains two types of photoreceptors: rods and cones.
• The optic nerve is a bundle of nerve fibres that carry information from the retina to the brain
• The tapetum lucidum is a reflective layer in the choroid that enhances visual sensitivity under low light conditions and provides the retina with a second opportunity for stimulation.
• Light passes through the conjunctiva, cornea, aqueous humour, pupil, lens, and vitreous humour before hitting the retina.
• The fovea is the area with the highest density of photoreceptors.
• label the following

  A) sclera

  B) choroid

  C) fovea

  D) optic disc

  E) optic nerve

  F) retina

  G) lateral rectus muscles

  H) ciliary body

  I) iris

  J) pupil

  K) cornea

  L) aqueous humour

  M) lens

  N) vitreous humour

  O) medial rectus muscles
• the function of the sclera is to protect the eyeball
• the function of the choroid is to supply blood to the outer layers of the retina
• the function of the optic disc is where the optic nerve enters the eye
• the function of the optic nerve is to carry visual information from the retina to the brain
• the function of the fovea is to have high concentration of cones which gives us sharp vision
• the function of the lateral rectus muscle is to move the eye outwards (abduction)
• the function of the ciliary body is to control the shape of the lens by changing its curvature
• the function of the iris is to control the amount of light entering the eye
• the function of the medial rectus muscle is to move the eyes inwards (adduction)
• the function of pupil is to control the amount of light entering the eye and the amount of light leaving the eye
• Cornea and lens bends the light.
• Aqueous humour provides nutrients to the cornea and lens