Exam 3: Orbit and Contents

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Exam 3: Orbit and Contents
2012-07-04 17:01:31
anatomy orbit

review of 7/3 lecture on orbit and contents for exam 3
Show Answers:

  1. The eyeball consists of how many layers of tissue?
  2. What is included in the outer fibrous layer of the eyeball?
    • opaque sclera
    • transparent cornea 
  3. Where is the opaque sclera of the eyeball?
    posterior 5/6's
  4. Where is the transparent cornea of the eyeball?
    anterior 1/6
  5. What part of the eye is the sclera?
    white part
  6. What is the middle layer of the eye known as?
    middle vascular layer
  7. What does the middle vascular layer of the eye include?
    • choroid
    • ciliary body
    • iris  
  8. The sclera is continous with what?
    cornea in outer layer
  9. What is the inner layer of the eye?
  10. What is contained in the retina?
    sensory receptors for light
  11. What are sensory receptors?
    rods and cones
  12. What does light pass through before it strikes the retina?
    numerous refractive media
  13. What are refractive media?
    • cornea
    • aqueous humor in anterior/posterior chambers
    • lens 
    • vitreous humor   
  14. Is the aqueous humor continuously produced and absorbed?
  15. What does the lens do?
    focuses light onto macula
  16. What causes glaucoma?
    • disruption in balance in prduction and absorption of aqueous humor
    • excess aqueous humor
  17. The lens is suspended by what?
    tiny ligaments attached to ciliary muscle
  18. Contraction and relaxation of the ciliary muscle results in:
    accommodation of lens
  19. What is accommodation?
    changing shape of lens
  20. What is accommodation essential for?
    focusing light rays comming from differnet distance onto the retina
  21. What nerve supplies the ciliary muscle?
    parasympathetic motor fibers in CN III
  22. How many smooth muscles does the iris contain?
  23. What do the smooth muscle of the iris do?
    regulate size of pupil
  24. Where is the optic nerve attached to the eyeball?
    posterior side of eyeball in position of blind spot of retina
  25. Does the blind spot contain rods or cones?
  26. What is included in the blind spot?
    central artery of retina
  27. What surrounds the optic nerve?
    all three layers of meninges
  28. What does increase in intracranial pressure do?
    affect central artery of retina
  29. Where is the central artery of the retina?
    within the optic nerve
  30. An increase in intracranial pressure due to closed-head injury can be detected how?
    visualiing changes in blind spot and arteries supplying retina
  31. Where is the highest concentration of cones?
    the macula
  32. Where is the sharpest vision?
  33. what is the optic disc?
    where optic nerve enters eye
  34. Where does the optic nerve enter the eye?
    through fovea centralis
  35. How many extraocular muscles are there?
  36. Where do extraocular muscles insert?
    into eyeballs
  37. Contraction of extraocular muscles causes what?
    eyeballs to move in various directions to track objects in visual field
  38. What is elevating the eye?
    looking up
  39. What is abducting the eye?
    turns eye outward
  40. What is adducting the eye?
    turns eye inward
  41. What holds the superior oblique in place?
  42. Which muscle lies on top of superior rectus?
    levator palpebrae superioris muscle
  43. The superior part of the levator palpebrae superioris muscle consists of what type of muscle fibers?
    skeletal muscle fibers
  44. What is the inferior part of the levator palpebrae superioris known as?
    superior tarsal muscle
  45. The inferior part of the levator palpebrae superioris muscle consists of what type of muscle fibers?
    smooth muscle fibers
  46. Patients with oculomotor nerve palsy are unable to:
    elevate upper eyelid voluntarily
  47. Why are patients with oculomotor nerve palsy unable to elevate upper eyelid voluntarily?
    levator palpebrae superiorir is paralyzed
  48. What doesa lesion of the cervical sympathetic chain ganglia cause?
  49. What is ptosis?
    drooping of upper eyelid
  50. What is ptosis a sign of?
    cervical sympathetic trunk injury
  51. Horner's syndrome:
    • cervical sympathetic trunk injury
    • loss of sympathetic innervation to head and neck region
    • ptosis (drooping of upper eyelid)  
  52. What supplies blood to the contents of the orbit?
    ophthalmic artery and its branches
  53. The ophthalmic artery is the first branch of which artery?
    internal carotid artery in cranial cavity
  54. What is the sole blood supply of the retina?
    central artery of the retina
  55. The central artery of the retina is a branch of what?
    ophthalmic artery
  56. Where is the central artery of the retina?
    in the optic nerve
  57. The contents of the orbit are drained by:
    ophthalmic veins
  58. Ophthalmic veins have connections with which veins?
    • facial vein
    • cavernous sinus 
  59. What is the only blood supply to the retina?
    central artey and vein of retina
  60. What is found in the anterior chamber of the eye?
    aqueous humor
  61. What is found in the posterior chamber of the eye?
    aqueous humor
  62. When is aqueous humor produced?
  63. Where is aqueous humor produced?
    by cells in eye in posterior chamber
  64. How does aqueous humor reach the anterior chamber from the posterior chamber?
    through the pupil
  65. Where is aqueous humor reabsorbed?
    venous sinuses
  66. If aqueus pressure is high, this causes:
  67. What is the path of light through the eye?
    light-cornea (bends)-pupil-lens (bends)-macula (focus)
  68. What type of muscle fibers does the levator papilbrae superioris have?
    skeletal and smooth
  69. Sympathetic neurons of the levator papilbrae superioris are found where?
    within carotid plexus