Download The Sensory System * Ear/Nose/Tongue/Skin

Health Science 1
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Sense organ especially adapted to pick up
sound waves and send these impulse to the
auditory center of the brain which lie in the
temporal area just above the ears.
The receptor for hearing is the organ of Corti,
within the cochlea of the inner ear.
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Ear also involved with equilibrium (balance)
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Pinna
◦ Outer part of ear
◦ Collects sound waves and directs them into the
auditory canal
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Auditory Canal
◦ Lined with sebaceous or ceruminous glands which
secrete a waxlike or oily substance called cerumen
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Tympanic Membrane
◦ The eardrum (separates the outer from the middle
ear)
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The cavity in the temporal bone
Connects with the pharynx (throat) by the
eustachian tube.
Eustachian tube – equalizes pressure between
the middle ear and the outside atomsphere.
Contains 3 tiny bones
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Hammer
◦ Malleus
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Anvil
◦ incus
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Stirrup
◦ Stapes
◦ These transmit sound waves from the ear drum to
the inner ear
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Contains membrane lined channels which lie
deep within the temporal bone.
Cochlea (organ of hearing)
◦ Contains a membranous tube called the cochlear
duct.
◦ This duct is filled with fluid that vibrates when the
sound waves from the stirrup bone strike against it.
◦ Cochlear duct contains delicate cells which make up
the organ of Corti.
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Organ of Corti – receptor for hearing
◦ Hairlike cells that pick up vibrations caused by the
sound waves against the fluid
◦ These are then transmitted through the auditory
nerve to the hearing center of the brain
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Semicircular canals (3)
◦ Also within the inner ear
◦ Contain liquid and hairlike cells that bend when the
head and body move. Impulses are sent to the
cerebellum, to maintain balance
◦ Have nothing to do with hearing.
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Sound waves > pinna >auditory canal >
tympanic membrane > ear ossicles (bones) >
stimulate the receptors in the cochlea >
cochlear nerve > temporal lobe of the brain
for interpretation
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External Otitis
http://www.nlm.nih.gov/medlineplus/ency/a
rticle/000622.htm
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Infection in the middle ear
Usually causes earache
Common complication of common cold in
children
Treatment with antibiotics
If a build up of fluid in ears can be relieved by
a myringotomy (tubes in the ears)
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Bones of the middle ear harden (stapes)
The bones become immovable
Common cause of deafness in young adults.
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Treat with stapedectomy and replacement
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Condition that affects the semicircular canals
of the inner ear, causing vertigo (dizziness)
Cause is unknown
Can occur at any time without warning
Usually accompanied by nausea and vomiting
and ringing in the ears
Treat with bedrest
Can take medication for dizziness
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Ringing in the ears
May be caused by impacted wax, otitis media,
otosclerosis, loud noise
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Normal hearing loss die to the aging process
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Hearing aides
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Could be conductive or sensorinerural
Occurs when sounds to
the inner ear are blocked
by wax or fluid
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Could be caused by
abnormal bone growth
Conductive hearing
loss
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Can be a result of
damage to parts of
the inner ear or
auditory nerve.
Could result in
complete deafness
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Possibility for
cochlear implants
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Sensorineural loss
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Can detect about 10,000 different smells
which account for about 90% of what we think
of taste.
Made up of the Nasal Cavity and Olfactory
epithelium
◦ Contains supply of nerve cells with specialized
receptors which send signals to the olfactory nerves
in brain
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Deviated Nasal Septum
◦ Bend in the cartilage structure of the septum.
◦ Symptoms include blockage of the airflow through
one nostril
◦ Difficulty sleeping
◦ Snoring
◦ Sometimes relieved by external adhesive strip
across the nose
◦ May need surgical repair
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Growths in the nasal cavity
Could be associated with rhinitis
Surgical removal in severe cases
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Inflammation of the lining of the nose which
may cause nasal congestion, drainage,
sneezing or itching.
Cause could be allergies, infection
Could be fumes, odors, drugs
Treatment of symptoms (remove causative
agent)
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Large mass of muscle tissue containing
Papillae.
Aides in the beginning process of digestion
Papilla contain taste buds for sweet, sour,
salty, and bitter
Receptors of taste buds send stimuli through
three cranial nerves to the cerebral cortex for
interpretation.
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Glossitis
http://www.nlm.nih.gov/medlineplus/ency/a
rticle/001053.htm
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Red
irritated
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Thrush is a yeast infection of the mucus
membrane lining the mouth and tongue.
a fungus called Candida overgrows in your mouth
The following factors can increase your chances
of getting thrush:
Being in poor health
Being very old or very young
Having an HIV infection or AIDS
Long-term use or high dose antibiotics
Receiving chemotherapy or drugs that weaken the
immune system
◦ Taking steroid medications
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Site of many nerve endings
A square inch contains 72 feet of nerves and
hundreds of receptors
Able to detect pain and temperature