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Sense of Sight

Sense of Sight . Cameras operate like the human eye. The human eye has approximately 576 MP. . Light Refraction. Light bends around objects Images viewed by the eye are upside down. R.O.Y.G.B.I.V

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Sense of Sight

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  1. Sense of Sight Cameras operate like the human eye. The human eye has approximately 576 MP.

  2. Light Refraction Light bends around objects Images viewed by the eye are upside down

  3. R.O.Y.G.B.I.V Rainbows are seen after rain because light is passing through water droplets.  This separates the white light into the individual colors of the spectrum

  4. The Eye as an Optical Device

  5. Accommodation • Lens changes shape to focus on objects using ciliary muscles and suspensory ligaments • Otherwise, image appears blurry

  6. We have difficulty interpreting images that are upside down Which one is the real Mona Lisa?

  7. THE EYE • The eye is in the orbit of the skull for protection. • Within the orbit are 6 extrinsic eye muscles, which move the eye. • There are 4 cranial nerves: Optic (II), Occulomotor (III), Trochlear (IV), and Abducens (VI) which innervate the eye.

  8. Can You Guess the Celebrity Eyes? Visual Accessory Organs • Eyelid • Conjunctiva • Lacrimal Gland • Extrinsic Muscles These are organs that do not directly contribute to your sense of sight or vision, but do play a role in the health and functionality of the eye. Choices: Miley Cyrus, Kristen Stewart, Jennifer Lawrence, Demi Lovato

  9. Eyelid Covers and protects the eye, thin skin Skin will not protect you from intense radiation, that’s why we use special goggles in a tanning bed

  10. CONJUNCTIVA is a covering around the eye and under the eyelids. PINK EYE - also known as CONJUNCTIVITIS  (from bacteria, very contagious) Pink Eye Slide Show from Web MD

  11. Extrinsic Eye Muscles Moves the eyeball

  12. GLANDS OF THE EYE LACRIMAL GLANDS are the largest set. They are on the superior lateral eyelid and they produce tears, which drain into the nasal cavity via the LACRIMAL DUCT. The function is to moisten and lubricate the eye surface, and it has enzymes to kill bacteria (which thrive in warm, moist conditions).

  13. OUTER TUNIC • Cornea - transparent, focuses light rays • Sclera – continuation of cornea, going toward the back of the eye (white of the eye) • Optic Nerve – exits at the optic disk and transmits visual information from the eye to the brain. Keratoconus is an eye condition in which the normally round cornea thins, causing a cone-like bulge to develop.

  14. MIDDLE TUNIC • Choroid Coat – contains blood vessels • Lens – focusing light • Iris – colored portion of the eye • Aqueous humor – liquid surrounding the lens • Pupil – opening for light to enter

  15. Figure 16.7a

  16. INNER TUNIC • Retina - visual receptor cells • Optic Disc – where nerve fibers leave the eye, creating the blind spot • Vitreous Humor – supports internal parts, fluid • Fovea Centralis – area of retina with sharpest central vision (reading, driving)

  17. Retina The retina is made up of PHOTORECEPTORS, which are sensory nervesfor light.

  18. RODS = monochromatic (light/dark), much more sensitive to light for action potential initiation vs. CONES = color vision

  19. Light is focused primarily by the cornea — the clear front surface of the eye, which acts like a camera lens. The iris of the eye functions like the diaphragm of a camera, controlling the amount of light reaching the back of the eye by automatically adjusting the size of the pupil (aperture). The eye's lens is located directly behind the pupil and further focuses light. Through a process called accommodation, this lens helps the eye automatically focus on near and approaching objects, like an autofocus camera lens. Light focused by the cornea and lens (and limited by the iris and pupil) then reaches the retina — the light-sensitive inner lining of the back of the eye. The retina acts like an electronic image sensor of a digital camera, converting optical images into electronic signals. The optic nerve then transmits these signals to the visual cortex located in the occipital lobe after the signal gets relayed from the thalamus.

  20. PUPILS • When you are looking at someone you love, your pupils dilate, and they do the same when you are looking at someone you hate. • FIGHT OR FLIGHT!  more light enters

  21. What causes red-eye? The flash on a camera is bright enough to cause a reflection off of the retina -- what you see is the red color from the blood vessels (choroid coat) .Many cameras have a "red eye reduction" feature. In these cameras, the flash goes off twice -- once right before the picture is taken, and then again to actually take the picture. The first flash causes people's pupils to contract, reducing "red eye" 

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