Special Senses- The Eye

Question 1

vision 
# sensory receptors in eyes?
what do eyes detect?
wavelengths they detect?
which colors have which wavelengths?
how is color seen?
white vs black light?

Answer 1

more then 1/2 of all sensory receptors located in eyes

• eyes detect visible light
  
  • 400 to 700 nm wavelengths
  • exhibits colors
    
    • 400 nm violet
    • 700 nm red
  • color seen is wavelength reflected
    
    • white light: all wavelengths reflected
    • black: all wavelengths absorbed

Question 2

accessory structures of the eye (4)

Answer 2

eyelids
eyebrows & eyelashes
lacrimal apparatus
extrinsic eye muscles

Question 3

eyelids

which muscles move? function of eyelids?

Answer 3

orbicularis oculi- closes lid
levator palpebrae superioris- opens lid (lifts up)
FUNCTION: shade, protect, lubricate eye

Question 4

2 different parts of eyelid?

Answer 4

tarsal glands or Meibomian glands

Conjunctiva

Question 5

tarsal glands or Meibomian glands

description? function?

Answer 5

modified sebaceous glands
keep eyelids from adhering to each other
(under upper eyelid) (every time blink, secrete seb. oils)

Question 6

Conjunctiva

description? function?

Answer 6

(THIN, contains tiny blood vessels)
lines eyelids & attached to “white” of the eye
-conjuctivitis: “pink eye” (inflammation)
protective mucus membrane

Question 7

Eyebrows & eyelashes

description? function? contains? their function?

Answer 7

protects from foreign substances, perspiration, direct sunlight

 - contains Sebaceous Glands 2 eyelash follicles
        - lubricaiton
        - Sty: inflammation of sebaceous gland (can affect eyesight if not treated, pimple on eye)

Question 8

Lacrimal apparatus

description? function?

Answer 8

structures that produce & drain tears

-function: Protect, Clean, Lubricate the eyeball

Question 9

Extrinsic Eye Muscles

description? # of muscles that control movements? which?

Answer 9

Extend from bony orbit to sclera (white) of eye

• surrounded by fat tissue
• 6 muscles control eyeball movements
  
  • controlled by cranial nerves 3, 4, 6