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