Special Senses Class Notes

Vision:

• Lacrimal Sac: From corner of eye to nostril

  • Used for drainage

• Lacrimal gland: Above eye in lacrimal fossa in frontal bone

• Tarsal glands/Mewbian glands: Tunnels under the eyelid

  • Makes oil, which floats on water of tears

  • Ensures no scraping on salt water tears

  • When blocked, it is called a STYE —> Use heat to remove

• Extraocular muscle

  • CNIII - Oculomotor (alsp raising lid)

    • Superior rectus

    • Inferior rectus

    • Medial rectus

    • Inferior oblique —> Up and out

  • CNIV -

    • Superior oblique —> Down and out

  • CNVI -

    • Lateral rectus

• Iris = Colored part of eye

  • Colored by melanin

    • Blue because light is refracted by melanin

• Muscles

  • Sphincter pupillae - CN III

    • Contracts/expands based off of amount of light

  • Dilator pupillae - SNS

    • Pulls the pupil larger

    • Autonomic

• Emetropia - 20/20 Vision

  • 4 media are working properly, so that all light is focused onto the bulls-eye

• Myopia - Near-sightedness (-)

  • Eye is longer —> everything is working properly, but retina isn't where it is “supposed to be”; light is scattered, and everything is blurry

  • Fixed by concave lens —> Cave in center scatters light so it reconvenes later

• Hypertropia - Far-sightedness (+)

  • Eye is shorter —> Everything is working properly, except retina is too close —> Light is scattered, everuthing is blury

    • All chidlren are far sighted

  • Fixed by convex lens —>

• Presbyopia —> Hardening of lens

  • Lens cannot change shape

  • Cannot see near

• Astigmatism —> Shape of eye and cornea is wrong

Cones:

• Cyanolabe: Blue

• Chlorolabe: Green

• Erythrolabe: Red

Rods: Rhode