Special SensesSpecial Senses

Eyes, Ears, Nose, & ThroatEyes, Ears, Nose, & Throat

Special SensesSpecial Senses

The special senses are The special senses are those organs and those organs and receptors that are receptors that are associated with touch associated with touch (sensory receptors), (sensory receptors), vision, hearing, smell, vision, hearing, smell, and taste.and taste.

Special sensory receptors Special sensory receptors include taste buds, include taste buds, special cells in the nose, special cells in the nose, the retina of the eye, and the retina of the eye, and the Corti (special cells in the Corti (special cells in the organ of the ear).the organ of the ear).

The sensory The sensory receptors for receptors for pain, pain, temperature, temperature, and pressure and pressure are found all are found all over the body: over the body: in the skinin the skin connective connective

tissuetissue musclemuscle

The EarThe Ear

The ear is the organ that controls the special senses of hearing and balance.

It transmits impulses from sound waves to the auditory nerve (vestibulocochlear), which carries the impulses to the brain for interpretation as hearing.

The Ear is divided into three main sections:The Ear is divided into three main sections:

* The Outer Ear* The Outer Ear

* The Middle Ear* The Middle Ear

* The Inner Ear* The Inner Ear

Diagram of 3 Ear Diagram of 3 Ear SectionsSections

http://www.youtube.com/watch?v=WSsqaBwi4Zc&feature=c4-overview-vl&list=PLD9BCCBD95EA743F3

Ear DiseasesEar Diseases

Hearing LossHearing Loss

Hearing Loss: classified as either conductive or sensory

Conductive: due to sound waves not being conducted to inner ear causes: wax, foreign body obstruction,infection,

ruptured tympanic membrane. TX: eliminate cause, surgery, hearing aids

Sensory: due to damage to the inner ear or auditory nerve Usually cannot be corrected Cochlear implants can improve severe hearing

loss.

MENIERE’S DISEASE

Collection of fluid in labyrinth of inner ear and a degeneration of hearing cells in cochlea and vestibule.

S/SX: severe vertigo or dizziness, tinnitus (ringing of the ear), n/v, loss of balance and the tendency to fall.

TX: Drugs to decrease the fluid and antihistamines, drain the fluid, surgery to destroy the cochlea in severe cases, but this will cause permanent deafness.

OTITIS EXTERNA

Otitis Externa: Inflammation of the external auditory canal

Causes: pathogenic organism such

as bacteria/virus Swimmers ear is one form,

caused from swimming in contaminated water

Inserting bobby pins, fingernails or cotton swabs in the inner ear can also cause this condition

S/SX: pain, swelling TX: antibiotics, warm moist

compresses and pain medications

Otitis Media: Inflammation of the middle ear

Causes: bacteria or virus frequently follow a sore

throat because organisms can enter the middle ear through eustachian tube

S/Sx: severe pain, fever, vertigo, dizziness, n/v, buildup of fluid in the middle ear

TX: Antibiotics, pain medicine, if severe surgery

OTITIS EXTERNA

Bug in earEar wax build up

normal Otitis Externa

Perforation of ear drum

Ear DiseasesEar Diseases

Acute Otitis media

Chronic Otitis Media

normal

Perforated ear drum

Tube placed in ear

Abcess formed on girlin 3rd world country with

untreated Otitis MediaWas surgically drained and treated

The EyeThe Eye

Is the organ that controls the special Is the organ that controls the special sense of sightsense of sight

Receives light raysReceives light rays

Transmits the rays to the Optic NerveTransmits the rays to the Optic Nerve

Optic Nerve takes the rays to the Optic Nerve takes the rays to the brain where they are interpreted as brain where they are interpreted as vision/sightvision/sight

The Eye Continued…The Eye Continued…

The eye is well protected partially enclosed in a bony socket in the skull.

Eye lids and Eyelashes help keep out dirt and pathogens

Lacrimal Glands produce tears that… constantly moisten and cleanse the eye tears flow across eye and drain through the

lacrimal duct into the nasal cavity.

Conjunctiva: Mucous Membrane that protects the eye Lines the eyelids and covers the front of the eye

The Three Layers of The Three Layers of the Eyethe Eye

11stst layer layer

Sclera: *Outermost layer *Tough Connective Tissue *The White of the eye *Maintains the shape of the eye *Extrinsic muscles, responsible for moving the eye are attached to the outside of the sclera

*Cornea: a circular transparent part on the front of the sclera that allows light rays to enter the eye

22ndnd layer layer

Choroid Coat:

Middle layer of the eye

Interlaced with many blood vessels that nourish the eyes

Pupil: Hole in the front of the Choroid Coat allows light rays to enter

Iris: Colored portion of the eye Muscle that controls the size of the pupil and regulates the amount of light entering the eye

Diagram of EyeDiagram of Eye

33rdrd layer layer

Retina:

Intermost layer of the eye

Made of many layers of nerve cells that transmit the the light impulses to the optic nerve.

Two special types of cells in the Retina: Cones: *used mainly for light vision, sensitive to

color *located in a depression on the back surface

of the retina called the fovea centralis (the

area of sharpest vision

Rods: used for dark or dim vision

Diagram of RetinaDiagram of Retina

Other Special StructuresOther Special Structures

A. Lens: *circular structure located behind the pupil *Suspended in position by ligaments * Refracts or bends light rays so the rays

will focus on the retina.

B. Aqueous humor: *clear, watery fluid *fills space between cornea and

iris *helps maintain the forward curvature of the eyeball *bends or refracts light rays

C.Vitreous humor: *Jelly-like substance: fills area behind

the lens *helps maintain shape of

eyeball*also bends/refracts light rays

Diseases Of The Diseases Of The EyeEye

Amblyopia known as “Lazy Eye” commonly occurs in childhood results in poor vision in one eye and

dominance of the other eye

Treatment: covering the good eye to stimulate the lazy eye exercises to strengthen the muscles

corrective lenses or surgery

**If not treated before 8 to 9 years of age, blindness in affected eye can occur.

AstigmatismAstigmatism Blurred vision caused by an abnormal shape or

curvature of the cornea Treatment: Corrective Lenses correct the condition

CataractCataract Normally clear lens becomes cloudy or opaque Occurs gradually due to aging (some are born with)

S/SX: Blurred vision and halos around lights Gradual loss of vision Milky White pupil in later stages TX: Surgical removal of the lens Implanting an introacular lens or prescribing

glasses of contact lenses corrects the vision and

compensates for the removed lens.

Examples of Examples of Cataracts..Cataracts..

Conjunctivitis or Pink EyeConjunctivitis or Pink Eye

Contagious inflammation of the conjunctiva Usually caused by a bacteria or virus

S/SX: redness, pain, swelling and pus formation

TX: antibiotics, frequently as an eye ointment

Can cause damage if not treated properly.

Examples of Pink EyeExamples of Pink Eye

GlaucomaGlaucoma

Condition resulting from increased intraocular pressure (inside the eye)

Caused by an excessive amount of aqueous humor. Common after age 40 and a leading cause of

blindness Tonometer: an instrument used to measure

intraocular pressure and is used to check for this condition in eye exams

S/SX: loss of peripheral vision (side), halos around lights, limited night vision, and a mild aching

TX: Controlled with medications to decrease the pressure

Severe cases: Surgery to create an opening for the flow of aqueous humor.

Glaucoma ExamplesGlaucoma Examples

The arrows show the outer edge of the "cup" of the optic

nerve. This nerve has glaucoma related damage. Compare this optic nerve to the normal one shown above

and to the left!

Glaucoma VisionGlaucoma Vision

Occurs when light rays are not refracting properly andThe image focuses behind the retina.

Corrected with the use of Convex lenses.

Presbyopia:

Farsightedness caused by a loss of elasticity in lens.

Occurs as a result of the normal aging process

Treat with corrective lenses

Hyperopia/ Farsightedness

Occurs when light rays are refracted too sharpley and the image focuses in front of the retina

Vision is corrected with the use of concave lenses(can see near, but not far)

Radial Keratotomy (RK) : Is the surgery that can be used to correct Myopia.Small incision made in the cornea to flatten it so light rayshit it correctly.Laser can be used to flatten the cornea without cuttingCan correct myopia and eliminate the need for corrective lenses.

Myopia/ Nearsightedness

Strabismus:

Condition in which eye do not move or focus together.

Eyes may move inward (cross-eyed), outward or up or down.

TX: eye exercises, covering the good eye, corrective lenses, and surgery on muscles moving in the eye.

Example of StrabismusExample of Strabismus

Retinal Detachment: usually due to injury

Hemorrhage of the Vitreous humor

Double Vision

These images demonstrate how individuals with normal color vision, and abnormal color vision, might view this color vision test. Those with normal vision would see the number "3" as shown on the left. With mild color blindness (as is present in about 8% of males), the number may be misread as a "5", as shown in the middle. With total color blindness, no number or pattern is visible, as shown on the right (rare).

How to read and understand a glasses or contact prescription.

Glasses prescriptions are not difficult to understand. First of all, the right eye is usually listed first, and is noted by O.D. The left eye is O.S. The prescription has mainly three parts: the sphere, the cylinder and axis, and the add.

The sphere determines nearsightedness or farsightedness. No sphere is noted as "plano". If the power is a minus, it is a nearsighted prescription. If it is a plus, it is farsighted.

Mild prescriptions are in the range of plus or minus 1 to 3, while high prescriptions are over plus or minus 5 to 7.The cylinder and axis represent the astigmatism correction.

Cylinder is power in a certain direction, and can be written as a plus or a minus power (ophthalmologists usually use plus, optometrists use minus). The axis is the direction of the power. It is measured in degrees, from 1 to 180. Axis 180 is perfectly horizontal, while axis 90 is straight up and down. This is like the degrees on a protractor. Most people would not notice a change in axis of 5 to 10 degrees, unless the cylinder power is fairly high (say, over +2.00). Many people do not tolerate glasses with high cylinder due to distortion.The add is additional power placed in a bifocal. This is always a plus power, and is similar to a plus farsighted sphere power. This usually ranges from a +1.00 to +3.50. The average highest power that people need in a bifocal for reading is a +2.25.

Contact lens prescriptions are similar to glasses prescriptions. However, they also state the name and type of contact lens being used, any tint in the lens, the base curve of the lens, and the diameter. The power of contact lenses are usually just plus or minus sphere powers. Only with special astigmatism correcting toric lenses is there a cylinder power (always a minus power for contacts) and an axis.The base curve determines how tight the lens is on the eye. It usually ranges from an 8.3 (tight) to a 9.0 (looser). In soft lenses, there are usually only a few choices for the base curve (tight, medium, or loose), and there may be only one diameter (the width of the lens). Hard lenses and gas permeable lenses are custom made and have more choices

The NoseThe Nose

Nose FactsNose Facts

The human nose can detect about 10,000 different The human nose can detect about 10,000 different smells.smells.

Smell accounts for about 90% of what we think is Smell accounts for about 90% of what we think is taste.taste.

Scientists are to do research on how smell may affect Scientists are to do research on how smell may affect learning, weight loss, aggression levels, and learning, weight loss, aggression levels, and behavior.behavior.

The Olfactory The Olfactory EpitheliumEpithelium

The olfactory epithelium is a plentiful supply of nerve The olfactory epithelium is a plentiful supply of nerve cells with special receptors.cells with special receptors.

The receptors send signals to the adjoining olfactory The receptors send signals to the adjoining olfactory bulbs, which is an extension of the brain.bulbs, which is an extension of the brain.

Then the stimulus is transmitted by the olfactory Then the stimulus is transmitted by the olfactory nerve to the limbic system, thalamus, and frontal nerve to the limbic system, thalamus, and frontal cortex.cortex.

The limbic system generates our basic emotions. The limbic system generates our basic emotions. (fear, affection, aggression, etc.)(fear, affection, aggression, etc.)

Nose DisordersNose Disorders

RhinitisRhinitis

Rhinitis is an inflammation of the Rhinitis is an inflammation of the lining of the nose.lining of the nose.

It causes nasal congestion, It causes nasal congestion, drainage, sneezing, or itching. drainage, sneezing, or itching.

Can be caused by allergies, Can be caused by allergies, infection, or other factors such as infection, or other factors such as fumes, odors, emotional changes, fumes, odors, emotional changes, or drugs.or drugs.

Treatments are eliminating Treatments are eliminating allergens or reducing exposure to allergens or reducing exposure to them and some antihistamines.them and some antihistamines.

Nasal PolypsNasal Polyps

Nasal Polyps are growths in the nasal cavity Nasal Polyps are growths in the nasal cavity that are associated with rhinitis.that are associated with rhinitis.

Severe cases may call for surgery to remove Severe cases may call for surgery to remove the polyps.the polyps.

Deviated Nasal SeptumDeviated Nasal Septum

Deviated nasal septum is a condition in Deviated nasal septum is a condition in which there is a bend in the cartilage which there is a bend in the cartilage structure of the septum. structure of the septum.

Symptoms include; blockage in airflow, Symptoms include; blockage in airflow, headaches, difficulty sleeping, loud headaches, difficulty sleeping, loud breathing or snoring, dry nose, and breathing or snoring, dry nose, and nose bleeds.nose bleeds.

Treatment has been surgical Treatment has been surgical correction.correction.

External adhesive strip placed across External adhesive strip placed across the nose can provide temporary relief the nose can provide temporary relief of breathing problems. It can also help of breathing problems. It can also help reduce snoring and temporary relief of reduce snoring and temporary relief of nasal congestion.nasal congestion.

Diagram of The Diagram of The NoseNose

The TongueThe Tongue

TongueTongue

The tongue is a mass of muscle tissue which The tongue is a mass of muscle tissue which has structures called papillae.has structures called papillae.

Taste buds are located on the papilla.Taste buds are located on the papilla. The receptors in the taste buds send stimuli The receptors in the taste buds send stimuli

through 3 cranial nerves to the cerebral cortex through 3 cranial nerves to the cerebral cortex for interpretation. for interpretation.

Four Main Tastes: 1) Sweet and salty tastes are at the tip of your

tongue 2) Sour tastes are on the side of your tongue 3) Bitter tastes are at the back of your tongue

Diagram of TongueDiagram of Tongue

Skin and General SensesSkin and General Senses

General sense receptors for pressure, heat, cold, touch and pain are located throughout the body in the skin and connective tissue.

Each receptor perceives only one type of sense.

Messages from these receptors allow the human body to respond to its environment.

Helps body to react to conditions that could cause injury

The EndThe End