Chap 11 The Sensory System Memmler’s A&P Chap 11 The Sensory System

Sensory system p236 Receives stimuli Initiates nerve impulse Sensory receptors Special senses General senses

Structure of the eye tunics Sclera Choriod Retina Chambers of the eye Eye p236 Structure of the eye tunics Sclera Choriod Retina Chambers of the eye Anterior chamber Posterior chamber

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 Hyperopia Myopia Astigmatism Strabismus Cataract Glaucoma Macular degeneration Retinopathy Retinal detachment Presbyopia

The Ear p245 Sections: Outer ear Middle ear Inner ear

Ossicles p 245

Inner ear p246

Disorders of the ear p247 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 p250 Tactile corpuscles are located in dermis of skin

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.