the eye

Cards (30)

  • What is the first structure that light meets when it enters the eye?
    The cornea
  • Why is the cornea transparent?
    To allow all light to pass through
  • What is the function of the cornea?
    To refract or bend light
  • What is the iris?
    The colored part of the eye that controls pupil size
  • What is the pupil?
    A gap in the middle of the iris that allows light to pass through
  • How does the lens differ from the cornea?
    The lens can change its shape to control light refraction
  • What is the role of the retina?
    To detect light and generate impulses
  • What is the function of the optic nerve?
    To transmit impulses from the receptor cells to the brain
  • What happens to the pupil in bright light conditions?
    The pupil constricts to allow less light in
  • What is the purpose of the iris reflex?
    To protect the retina from damage due to bright light
  • What are the two types of muscles in the iris?
    Circular muscles and radial muscles
  • How do circular muscles affect the pupil size in bright light?
    They contract to make the pupil smaller
  • What happens to the radial muscles in low light conditions?
    They contract to pull the pupil open
  • What are the steps involved in the iris reflex?
    • In bright light, circular muscles contract, and radial muscles relax, constricting the pupil.
    • In low light, circular muscles relax, and radial muscles contract, dilating the pupil.
  • What is the main purpose of the iris reflex?
    To control the amount of light entering the eye
  • What is the effect of the iris reflex on vision in different lighting conditions?
    It helps to protect the retina and improve visibility
  • What are the important parts of the eye involved in accommodation?
    The cornea, lens, ciliary muscles, and suspensory ligaments.
  • How does the shape of the lens change for nearby objects?
    The lens becomes short and fat to refract light more strongly.
  • What happens to the ciliary muscle when focusing on nearby objects?
    The ciliary muscle contracts and moves inwards towards the lens.
  • What is the role of the suspensory ligaments in accommodation?
    They attach the lens to the ciliary muscle and can be slackened or taut.
  • How does the lens adjust for distant objects?
    The lens is stretched out to reduce its curvature and refractive power.
  • What is long-sightedness medically known as?
    Hyperopia.
  • What is the problem in long-sightedness?
    The lens cannot refract enough light, causing images to appear blurry.
  • How do glasses help long-sighted individuals?
    They contain convex lenses that provide extra refracting power.
  • What is short-sightedness medically known as?
    Myopia.
  • What issue arises in short-sightedness?
    The lens refracts light too much, causing distant images to appear blurry.
  • How do glasses assist short-sighted individuals?
    They contain concave lenses that counteract the over-refraction of the lens.
  • What are the differences between hyperopia and myopia?
    • Hyperopia (long-sightedness):
    • Can see distant objects clearly.
    • Difficulty focusing on nearby objects.
    • Corrected with convex lenses.

    • Myopia (short-sightedness):
    • Can see nearby objects clearly.
    • Difficulty focusing on distant objects.
    • Corrected with concave lenses.
  • when focusing on a near object
    ciliary muscles contract and have a smaller diameter
    suspensory ligaments relax/loosen
    lens thickens and refracts light less strongly
  • when focusing on a distant object
    cillary muscles relax
    suspensory ligaments are pulled tight
    lens is pulled thin and refracts light less strongly