Memmler’s A&P
Chap 11 The Sensory System
Sensory system p236
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Receives stimuli
Initiates nerve impulse
Sensory receptors
Special senses
General senses
•Structure of the eye
•tunics
•Sclera
•Choriod
•Retina
•Chambers of the eye
•Anterior chamber
•Posterior chamber
Eye
p236
Protection for the eye
p 236-237
Skull
Eyelids
Eyelashes
Eyebrows
Conjunctiva
Tears
Pathway of light thru the eye p237
• Refraction
• Path of light:
– Cornea
– Aqueous humor
– Lens
– Vitreous body
– Light is focused on retina at
the fovea centralis
The Retina 238
– Rods
– Cones
Extrinsic muscles p239
•Allow the
eyes to
move
Intrinsic muscles
p240
•Form the iris
and the ciliary
muscle
Accomodation p241
Function of the iris p 240
Errors of refraction/eye disorders p242
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Hyperopia
Myopia
Astigmatism
Strabismus
Cataract
Glaucoma
Macular degeneration
Retinopathy
Retinal detachment
Presbyopia
The Ear
•Sections:
•Outer ear
•Middle ear
•Inner ear
p245
Ossicles p 245
Inner ear p246
Disorders of the ear p247
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Otitis media
Otitis externa
Hearing loss: conductive or sensorineural
Presbycusis
Sense of taste p249
• Gustation
• Taste buds located on tongue
• Taste contributes to appetite
Sense of smell p250
• Olfaction
• Receptors located in
epithelium of upper
nasal cavity
• Smell contributes to
appetite
Sense of touch
• Tactile
corpuscles
are
located in
dermis of
skin
p250
Sense of pain p252
• Widely distributed free nerve endings
• 2 pathways for pain transmission to brain
– Acute, sharp pain
– Slow chronic pain
Sense of position p251
• Proprioceptors: Receptors located in muscles,
tendons, joints relay impulses to the brain
(cerebellum)
Sensory adaptation 253
• When sensory receptors are exposed to a
continuous stimulus, receptors often adjust
themselves so that the sensation becomes
less acute.