special senses presentation for ap

8/14/2019 Special Senses Presentation for AP

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The Special Sense

Organs

By Tracey Spanbauer


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The Special Senses

Sight - eyes

Smell - nose

Hearing - earTaste - tongue


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The Role of Sense Organsin the Body

The sense organs convert environmentalstimuli into neural activity. The braininterprets this stimuli as sight, smell,

hearing, and taste.


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Sight: the eye


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How We See

Light enters the eye through the cornea. The ciliary body opens and closes the iris,

controlling the amount of light entering theeye. Next the light moves through the lens which

focuses it. When light reaches the retina

(which is made up of photoreceptor cellscalled rods and cones) it is translated into amessage of vision which travels from theretina via the optic nerve to the brain.


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Disorders that affect sightDisorders of the eye Myopia - nearsightedness & Hyperopia - farsightedness Astigmatism - refractions / not focusedDisorders of the eye muscles Strabismus - 2 images received by brain Nystagmus - involuntary movements of they eye-interfere w/ focus

Disorders of the cornea, iris, and lens Glaucoma - special type of optic neuropathy, usually associated with high

intraocular pressure extremely sensitive to light Cataract - a cloudy film over the lens of the eyeDisorders of the retina Diabetic retinopathy - changes in the eye's blood vessels caused by diabetes Macular degeneration - damage to a small area near the center of the retina;

difficulty in reading and writing


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Smell: the NoseThe nose is a facial organ that facilitates breathing and is used to smell.


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How We Detect Odors The nostrils carry odors into the nose when we

inhale. The odor molecules are dissolved in the mucous

lining inside of the nose. The odor is trapped.

The olfactory cell receptors, located just belowthe front of the skull are able to detectthousands of different types of odors at verylow concentrations.

Once the odor molecules are detected theolfactory receptors send nerve impulses to theolfactory bulb.

The cells then send signals to the brain via theolfactory nerve.


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Conditions that affect smell

sinus and other upper respiratory infections polyps in nasal cavities frontal head injuries

exposure to certain chemicals (insecticides & solvents) numerous medications radiation (treatment of head and neck CAs) other health issues that affect the nervous system (Parkinsons

or Alzheimers disease)

agingnot a condition but affects hearing


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Hearing: the Ear


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How we hear When something makes a noise, it sends sound waves (vibrations)

through the air. When the sound waves reach the eardrum it vibrates. These

vibrations are sent to the three smallest bones in your body. Firstthe hammer, then the anvil, and finally, the stirrup. Next thestirrup passes the vibrations to the cochlea.

Inside the cochlea there is thousands of hair-like nerve endingscalled cilia. The cilia vibrations travel via the auditory nerve tothe brain.

The brain translates this info. to tell you what you are hearing.

**The inner ear also detects changes in balance &head position.The core of this detection system is the semicircular canal (whichis filled with fluid). The movement of this fluid detects changes inhead position and contributes to balance.**


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Problems that affect hearing

Problems of Outer Ear:otitis externaperforated ear drum

Problems of the Middle Ear:

otitis mediaburst eardrumdamaged ossicles (hammer, anvil & stirrup)

Problems of the Inner Ear:

sensorineural hard of hearing & nerve damageTinnitusvertigoMenieres disease
http://www.hearingaidscentral.com/diseases_and_disorders_of_the_middle_ear.asphttp://www.hearingaidscentral.com/Diseases_and_Disorders_of_the_Inner_Ear.asphttp://www.hearingaidscentral.com/Diseases_and_Disorders_of_the_Inner_Ear.asphttp://www.hearingaidscentral.com/diseases_and_disorders_of_the_middle_ear.asp


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Smell and taste

are linkedtogether


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Taste: the Tongue


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How we taste The tongue has different shaped papillae. The papillae

help your tongue "feel" the texture of food by sendingmessages to your brain.

Located on the papillae are taste buds. The taste budshave finger like projections called microvilli.

Chemicals from the food we eat (tastants) dissolve insaliva and contact these openings to interact withproteins on the cells surface.

This causes electrical changes in the cells which sendsignals that ultimately go to the brain.


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How do we tell the difference

between tastes?The answer is how each food chemically reactsonce dissolved in salivia.

- Salt dissolves in the mouth allowing sodium ions to enter thetaste buds through the microvilli. When the Na+ accumulate, achemical change releases Ca++ that enter the cells which in turnrelease chemical signals called vesicles. Nerve cells receivethese messages and send a signal to the brain.

-Acids

generate H+ which block K+ on themicrovilli

and adifferent signal (sour) is sent to the brain.

- Sweet things do not enter the taste buds. Sweets cling to thesurface of taste buds and release enzymes that generate adifferent type of signal to the nerve cells to take to the brain.


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Common diseases/disorders

that affect taste phantom taste perception

hypogeusia ageusia dysgeusia Burning mouth syndrome


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Some causes of taste

problems Middle ear and upper

respiratory infections Radiation therapy for head and

neck CA Exposure to chemicals

(insecticides & somemedication)

Head injury Surgeries involving the ear,

nose, and throat Poor oral hygiene & dental

problems


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Wake UP!

If you have any questions (Kris)please feel free to use your A&P

book to find the answers.

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