Download What are the 5 Special Senses?

SPECIAL SENSES
Eye & Vision
Reading: Chapter 10
What are the 5 Special Senses?
INTRODUCTION:
nose (______________________)
ears (______________________)
eyes (______________________)
tongue (____________________)
skin (______________________)
The Eye & Vision
(1)External Structures: eyebrows, eyelids, eyelashes
a) conjunctiva
-lines eyelid & _______________
-protects and _____________
- Conjunctivitis ______________
b) lacrimal glands - ____________ and ____________ to eye
-produce tears
-why are tears important?
-tears ____________ over the eye
-drain into _________________ duct
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c) Extrinsic eye muscles - 6 that control eye movements (Table 10.2)
Superior Rectus - CIII look _______________________
Inferior Rectus – CIII  look _______________________
Medial Rectus – CIII  look ________________________
Lateral Rectus – CVI  look_____________________ (another word?)
Superior Oblique –CIV  look ___________________
Inferior Oblique – CIII  look ___________________
2) Internal Eye Structures
Introduction:
-a sphere
-slightly larger in men
- ____________ eye changes appearance of size
Outer layer = protective layer = ___________________
Middle layer = vascular layer = uvea________________
Inner layer = photoreceptors = _____________________
a) Outer layer of eye
1) sclera -white of the eye, ___________________ layer for shape.
2) cornea -clear layer _____________________ of eye
-__________ light rays
- _______ blood vessels…where does O2 come from?
3) anterior cavity
-b/w _______________ & iris
-filled w/_______________ humor
-fluid nourishes_______________
4) Canal of Schlemn - between the __________&____________
- filled with _________________________
-fluid _________________ the cornea
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b) Middle layer of eye
1) choroid coat -thin dark layer (____________ & blood vessels)
-nutrient _______________ to retina
-absorbs light (limits ______________)
2) ciliary body -__________ lens (________ muscle)
-____________ aqueous humor (glandular)
3) pupil
- _____________ in the iris that lets light in
4) Iris
-_____________________ portion of eye
-changes___________ amount of light entering eye
*radial muscles constrict =
pupil dilation ( ____ stimulation )
*circular muscles constrict =
pupil constriction ( ____ stimulation )
*Pupillary Light Reflex
5) lens
-2 layers of pigment for color
*posterior layer is ___________
*color of anterior layer controlled by _________
(85 to 90% of us have stable color by age 6)
-biconvex () shape
-important for ___________ light rays
-anchored by ___________ ligament
6) anterior cavity -space __________ to lens
-filled w/ _________________ humor
-divided into: a) anterior chamber –___________ to iris
b) posterior chamber –___________ to iris
7) posterior cavity -behind ________
-filled w/ _____________ humor  cannot be________
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c) Inner layer of eye
1) retina -inner most layer, very delicate, nutrients from___________
-has transducers for vision (light energy  AP)
a) rods:
Long____ receptors, for night vision.
found throughout retina.
b) cones: ___________ shape, for color vision.
concentrated in fovea centralis.
-nerve connections pass through ________ disk  brain
*“blind spot” at _________ disk
* _____________ or cones at this site
d) optic chiasm -optic nerves_______________ near sella turcica
-message sent to what lobe?_______________
3) Physiology of vision
a) transducers - rods & cones
1) rods
-for ________ vision
-20x more abundant than ________
-peripherally located
-contains_________ (need vit. A to make this)
-light ___________ rhodopsin
-in the dark, rhodopsin changes to_______ form
*takes time to re-activate
*about 30 min. for all rods to be activated
*_______________________
2) Cones -for color vision
a) concentrated in _______ centralis
b) specialized pigments similar to _________
c) ___ types: red, green, blue
d) ____________ active
e) produce a _________ image
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3) Lens function
-cornea & lens_____ light rays (cornea can’t focus)
a) lens can be _____________
b) rays bend __________…why is this important?
c) image is_________ on retina…brain interprets
as “right side up”
Ciliary Body (smooth muscle), responsible for focusing lens
d) Thin lens = _______________ vision
e) Thick lens = ___________ciliary body contracts
f) Near point = _________ point eye can focus on
g) Far point = in a normal eye is ______________
Focusing is called accommodation
4) Vision abnormalities: ( emmentropia = normal vision)
a) myopia - near sightedness
1) can see__________, but not____________
2) “eye too ________ or lens too strong”
3) image focuses in front of retina
4) __________ lens to correct, bend light rays___
5) ___________________surgery for some
b) Far sightedness
1) can see ____ but not _______
2) eye is too _____ or lens not_________enough
3) image focuses ______________ retina
4) __________ lens to correct, bend rays _____more
5) LASIK surgery for some
c) presbyopia - “old man’s eye”
1) lens looses ______________ with age
-can’t get ________ enough to focus image
2) near point moves __________
3) greatest changes after age _______
4) con_____ lens to correct
5) NOTE: hyperopia & presbyopia are NOT the same
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d) glaucoma - excessive pressure in eye
1) Aqueous humor not___________________ sufficiently
2) Pressure on____________ (nerves and blood vessels here)
3) Over time, vision can be___________
4) Loss of ______________ vision first
5) Treatment - drops that opens C of S
- surgery
e) cataracts - ______________ of the lens (protein changes)
1) Vision slowly __________
2) Surgery to replace ____________
3) Causes: ____, UV light, diabetes, genetics,
steroid use, ______________
f) astigmatism - _____________ or _____________ is warped.
1) Lenses to correct for the____________ in your cornea/lens
2) Glasses or Toric Contact Lenses
3) Surgery for some
g) color blindness - an ________________ disorder of the eye.
1) red-green CB______________, though blue CB does exist
2) red-green color blindness =
-sex linked trait, on _______ chromosome
-recessive gene
-more common in_______
The END
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