Download The Senses

The Senses
ST 110
Special Senses
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Organs and accessories related to:
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Vision
Hearing
Taste
Smell
Equilibrium
Types of Receptors
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Chemoreceptors
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Nociceptors
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Thermoreceptors
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Mechanoreceptors
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Photoreceptors
Sensations vs Perceptions
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Sensations- Feelings that occur when
the brain receives sensory impulse from
PNS.
Perceptions-conscious awareness of
sensation after interpretation.
Somatic Senses
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Involve the receptors associated with
skin, muscles, joints and visceral
organs.
Senses
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Touch- tactile receptors located in the
skin or just beneath it.
Pressure- stimulation of receptors in
deeper tissue
Receptors
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Touch and Pressure
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Free ends of sensory nerve fibers
Meissner’s corpuscles
Pacinian corpuscles
Senses Cont.
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Thermal- perceptions of degrees of
warmth and coolness
Temperature- free nerve endings
located beneath skin
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Heat receptors
Cold receptors
Senses Cont.
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Pain- free nerve endings that are
stimulated when tissues are damaged.
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Acute
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Chronic
Acute Pain
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Occurs very rapidly
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Not felt in deeper tissues
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Sharp/stabbing pain
Chronic Pain
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Slower onset
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Builds slowly in intensity (sec. or min.)
Visceral Pain
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AKA referred pain
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Pg 194 fig 9-1
Stretch Receptors
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Sensations of lengthening and
stretching muscles
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Golgi tendon organs
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Muscle spindles
Sensation of Sight
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Eye-sensory and receptor organ that
receives images and transmits them to
the brain.
Eye Terminology
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Optic
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Ocular
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Extraocular
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Intraocular
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OD
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OS
Accessory Organs
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Lacrimal apparatus
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Eyelids
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Extrinsic muscles
Lacrimal Apparatus
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Produce and drain lacrimal fluid (tears)
from eye
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Lacrimal gland
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Excretory lacrimal ducts
Eyelids
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Palpebrae
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4 layers
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Skin
Muscle tissue
Connective tissue
Conjunctiva
Protection
Extrinsic Muscles
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Rectus
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Oblique
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Pg 196 tbl 9-2
Conjunctiva
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Thin mucous membrane
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Stratified columnar epithelium
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Conjunctivitis
Structure of Eye
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Fluid filled hollow sphere
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3 layers (tunics)
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Outer
Middle
inner
The Eye
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Cornea
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Iris
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Pupil
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Lens
The Eye
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Presbyopia
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Retina
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Fovea centralis
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Aqueous humor
The Eye
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Vitreous Humor
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Optic disc
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Sclera
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Choroid
Actions of Eye
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Accommodation
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Convergence
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Emmetropia
Visual Acuity
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20/20
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Snellen Chart
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1st number-distance from the chart (20ft)
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2nd number- deviation from the norm based
on ability to read chart
Pathology of Eye
Glaucoma
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Increase IOP
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Loss of vision/blindness
Keratoplasty
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Corneal transplant
Inflammation
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Keratitis
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Iritis
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Conjunctivitis
Strabismus
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“cross eyed”
Cataract
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Lens loses transparency
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“milky”
Xerophthlamia
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Dry eye
Procedures
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Blepharoptosis
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Drooping of upper eyelid
Sensation of Hearing
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Ear-pick up and amplify sound waves for
interpretation
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Equilibrium
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3 regions
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External
Middle
Internal
External Ear
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Pinna
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External Auditory Canal
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Cerumen
Middle Ear
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Eustachian Tube
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Tympanic Membrane
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Mastoid Sinus
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Ossicles
Ossicles
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Transmit and amplify sound waves
Malleus (hammer)
Incus (anvil)
Stapes (stirrup)
Inner Ear
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AKA labyrinth
Cranial Nerve VIIItransmits info from
inner ear to brain
Normal Ear Actions
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Air Conduction
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Bone Conduction
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Sensorineural Conduction
Ear Pathology
Outer Ear
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Impacted cerumen
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Otalgia
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Otitis
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Otorrhagia
Middle Ear
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Eustachitis
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Mastoiditis
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Myringitis
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Otosclerosis
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Otitis Media
Inner Ear
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Labryinthitis
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Meniere’s Syndrome
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Tinnitus
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Vertigo
Procedures
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Otoplasty
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Mastoidectomy
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Myringotomy
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Stapedectomy
Hearing Loss
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Deafness
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Conductive Hearing Loss
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Noise-Induced Hearing Loss
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Sensorineural Loss
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Presbycusis
Sensation of Taste
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Taste bud-modified epithelial cells that
function as receptors
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Contain microvilli
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Types
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Sweet
Salty
Sour
Bitter
Sensation of Smell
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Olfactory receptors
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Nasal cavity
Olfactory pathways
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Nerve impulses travel through olfactory tract and
enter brain
Interpreted as specific odors
Closely associated with areas of brain important in
memories and emotion