Special Senses

Question 1

General senses of touch

Answer 1

• Temperature
• Pressure
• Pain

Question 2

Special senses

Answer 2

• Smell
• Taste
• Sight
• Hearing
• Equilibrium

Question 3

• Protection for the eye

Answer 3

– bony orbit
– cushion of fat
– eyelids and eyelashes

Question 4

• Lacrimal glands/apparatus

Answer 4

– Release tears continuously
– Salty solution that contains lysozyme
• produce tears which protect,
moisten, and lubricate the eye
•Contains antibodies and
lysozyme
Empties into the nasal cavity via
lacrimal canal

Question 5

• Conjunctiva

Answer 5

– lines eyelids and some of eyeball and eyelid edge and
ciliary glands (between eyelashes)
– lubricates the eye

Question 6

Extrinsic eye muscles

Answer 6

– Six muscles attach to the outer surface of the eye

– Produce eye movements

Question 7

structure of the eye (2 layers)

Answer 7

The fibrous layer 
Sclera
Cornea
• Choroid
• Ciliary body
• Iris 
• Pupil
Aqueous humour
Vitreous humour

sensory layer
• Retina
• Rods
• Cones

Question 8

Sclera

Answer 8

• White connective tissue layer

* Seen as the “white of the eye”

Question 9

Cornea

Answer 9

• Transparent, central anterior portion
• Allows for light to pass through
• Repairs itself easily
• The only human tissue that can be transplanted
without fear of rejection

Question 10

Choroid

Answer 10

– is a blood-rich nutritive layer

in the posterior of the eye

Question 11

Ciliary body

Answer 11

—smooth muscle

attached to lens

Question 12

Iris

Answer 12

—regulates amount of light entering eye

– Pigmented layer that gives eye color

Question 13

Pupil

Answer 13

: rounded opening in the iris

Question 14

Aqueous humour

Answer 14

• Anterior to the lens
• Clear watery fluid continuously secreted
• Provides nutrients and pressure
• Reabsorbed into venous blood through
• the canal of Schlemm

Question 15

Vitreous humour

Answer 15

• Posterior to the lens
• Provides pressure
• Gel like substance

Question 16

Retina

Answer 16

– Outer pigmented layer
– Inner neural layer contains
receptor cells (photoreceptors
rods and cones

Question 17

rods

Answer 17

– Most are found towards the edges of the retina
– Allow dim light vision and peripheral vision
– All perception is in gray tones

Question 18

cones

Answer 18

– Allow for detailed color vision
– Mainly in the centre of the retina
– Fovea centralis—area of the retina with only cones

3 types. colour blindness is a result of lack of cone type.

Question 19

otitis media

Answer 19

Infection of middle ear
fills with fluid
Common in young children due to shorter and straighter
eustachian tubes
Mainly bacterial but can be viral, often follows URTI
Pain, fever, hearing deficit
Treated with antibiotics and analgesia

Question 20

cataract

Answer 20

Clouding of the lens
Most are age related - lens proteins denature and degrade over
time
Higher incidence in smokers and diabetics
S & S
• Blurred vision
• Photosensitivity
• Difficulty driving at night

Question 21

glaucoma

Answer 21

increase in intraocular pressure (IOP) often due to obstruction of
outflow of aqueous humor (jelly like fluid between lens and
cornea)
untreated causes irreversible damage to the optic nerve and
retinal fibres resulting in a progressive, permanent visual loss or
blindness
Approx 15% blindness due to glaucoma
> 35 years.

Question 22

macular degeneration

Answer 22

• Slow progressive loss of macula (fovea) – very centre of the retina
where images focus
• responsible for central and near vision
• Most common form of vision loss in people over 55
• Dry macular degeneration
– Most common, cellular debris accumulates between the retina
and the choroid, causing atrophy and scarring to the retina
• Wet macular degeneration
– more severe, blood vessels grow up from the choroid behind the
retina which can leak exudate and fluid and also cause
hemorrhaging.