Unit L: Sensory System

Program Area: Health Occupations Education

Course Title: Allied Health Sciences I Number: 7211

Unit Title: Sensory System

SuggestedTime forInstruction: 5 class periods (90 minute classes)

10 class periods (55 minute classes)

Course Percent: 5%

Unit Evaluation: 100% Cognitive

-------------------------------------------------------------------------------

Competency: 1H12. Analyze the anatomy and physiology of the special senses.

Specific Objectives:

1H12.01 Explain the structure of the eye.

1H12.02 Analyze the function of the eye

1H12.03 Explain the structure and function of the ear, nose, and tongue.

1H12.04 Discuss characteristics and treatment of common sensory disorders.

Summer 2005 L.1

Unit L Master Outline

L. Sensory System

1H12.01 Explain the structure of the eye.A. Eye

1. 1” in diameter2. Protected by orbital cavity, eyebrows, eyelashes, eyelids3. Lacrimal glands – tears empty into nasal cavity4. Conjunctiva – thin membrane lines eyelids 5. Wall of eye made up of three coats

B. Sclera1. Outer layer2. White of the eye3. Tough coating, helps maintain shape of eye4. Muscles responsible for moving eye attached to sclera = extrinsic

musclesC. Cornea

1. Front of sclera (clear part) no blood vessels2. Transparent so light rays can pass through

D. Choroid coat1. Middle layer, contains blood vessels2. Opening in front is pupil3. Colored, muscular layer surrounding pupil is iris4. Intrinsic muscles – change size of iris to control amount of light entering

through pupilE. Lens

1. Crystalline structure located behind iris and pupil2. Elastic, disc-shaped, biconvex3. Situated between the anterior and posterior chambers

F. Anterior Chamber – filled with aqueous humorG. Posterior Chamber – filled with vitreous humorH. Retina

1. Innermost layer2. Light rays focus image on retina3. Image travels to the cerebral cortex via optic nerve4. Rods – sensitive to dim light5. Cones – sensitive to bright light and color6. Optic disc – on retina, known as blind spot, nerve fibers that form optic

nerve

1H12.02 Analyze the function of the eye.A. Eye

1. Protected by orbit, eyebrows, eyelashes, eyelids2. Lacrimal glands – tears empty into nasal cavity and clean the eyes3. Conjunctiva – secretes mucous to lubricate eyes

B. Sclera1. Tough coating, helps maintain shape of eye2. Extrinsic muscles - responsible for moving eye attached to sclera

C. Cornea - Transparent so light rays can pass through

Summer 2005 L.2

D. Choroid coat1. Middle layer, contains blood vessels2. Intrinsic muscles – change size of iris to control amount of light entering

through pupil3. Pupil constricts – gets smaller – in bright light4. Pupil dilates – gets larger – in dark light

E. Lens1. Where light rays are refracted2. Accommodation – change in the shape of the lens to allow for near and

distant visionF. Retina

1. Light rays focus image on retina2. Image travels to the cerebral cortex via optic nerve3. Rods – sensitive to dim light4. Cones – sensitive to bright light and color5. Optic disc – on retina, known as blind spot, nerve fibers that form optic

nerveG. Pathway of vision - Image travels through cornea, then pupil, through lens,

hits retina, picked up by rods and cones and carried to optic nerve where the brain interprets image

1H12.03 Explain the structure and function of the ear, nose, and tongue.A. Outer ear

1. Pinna (auricle)a. Visible earb. Collects sound waves

2. External auditory canal – ear canal3. Cerumen – ear wax, protects the ear4. Tympanic membrane – ear drum, separates outer and middle ear

B. Middle ear1. Cavity in temporal bone2. Connects with pharynx by Eustachian tube - which equalizes pressure in

the middle ear with outside atmosphere3. Bones - transmit sound waves from ear drum to inner ear

a. Malleus (hammer)b. Incus (anvil)c. Stapes (stirrup)

C. Inner ear1. Cochlea - spiral shaped organ of hearing, contains a membranous tube,

the cochlear duct – which is filled with fluid that vibrates when sound waves are transmitted by the stapes

2. Organ of Corti – delicate hairlike cells that pick up vibrations of fluid and transmit them as a sensory impulse along the auditory nerve to the brain

3. Semicircular canals – three structures in inner ear that contain liquid set in motion by head and body movements

4. Impulses sent to cerebellum to help maintain body balance (equilibrium)D. Pathway of hearing – ear to external auditory canal to tympanic membrane

to ossicles (malleus, incus and stapes) to cochlea to auditory nerve to brainE. Nose

1. Smell accounts for 90% of taste2. Tissue in the nose, olfactory epithelium, contains specialized nerve cell

receptors3. Those receptors stimulate the olfactory nerve to the brain

Summer 2005 L.3

F. Tongue1. Mass of muscle tissue2. Bumps on surface are papillae, they contain taste buds3. Receptors in taste buds send stimuli through 3 cranial nerves to cerebral

cortex

1H12.04 Discuss characteristics and treatment of common sensory disorders.A. Disorders of the eye

1. Conjunctivitis (Pink eye)a. Inflammation of conjunctival membranes in front of eyeb. Redness, pain, swelling and dischargec. Highly contagiousd. Rx – antibiotic eye drops

2. Glaucomaa. Excessive intraocular pressure causing destruction of the retina and

atrophy of the optic nerveb. Caused by the overproduction of aqueous humor, lack of drainage,

or agingc. Symps – develop gradually, mild aching, loss of peripheral vision,

halo around lightd. Tonometer – measures intraocular pressuree. Rx – drugs or laser surgery

3. Cataractsa. Lens of eye gradually becomes cloudyb. Frequently occurs in people over 70c. Causes painful, gradual blurring and loss of visiond. Rx – surgical removal of the lens

4. Sty (hordeolum)a. Abscess at the base of an eyelash in sebaceous glandb, Symps – red, painful, swollenc. Rx – warm, wet compresses

5. Eye injury - Glass or fragment in eye – cover eye and seek medical help, do not remove the object

6. Color blindnessa. Cones affectedb. Genetic disorder that is carried by female and transmitted to males

B. Vision defects1. Presbyopia

a. Lens loses elasticity, can’t focus on close or distant objectsb. Usually after age 40c. Rx – bifocals

2. Hyperopiaa. Farsightedb. Focal point beyond retina, eyeball too shortc. Convex lenses help

3. Myopiaa. Nearsightedb. Eyeball too longc. Concave lenses help

4. Astigmatisma.. Irregular curvature of the cornea or lens, causing blurred vision or

eye strainb. Rx – corrective lenses

Summer 2005 L.4

5. Diplopia – double vision6. Strabismus (cross-eyed)

a. Eye muscles to not coordinate their actionsb. Usually in childrenc. Rx – eye exercises or surgery

7. Ophthalmoscope – instrument for viewing inside the eye8. Snellen eye chart – chart that uses letters or symbols in calibrated

heights to check for vision defectsC. Disorders of the ear

1. Hearing lossa. Hearing is fragile, loud noise over period of time can cause hearing

loss b. Symps – tinnitus (ringing in ears) and difficulty understanding what

people are saying2. Otitis Media

a. Infection of middle earb. Often complication of common cold in childrenc. Rx – antibioticsd. Myringotomy – tubes inserted through tympanic membrane to relieve

pressure3. Otosclerosis

a. Chronic , progressive middle ear disorderb. Stapes becomes spongy and then hardens, becoming fixed and

immobilec. Rx – stapedectomy and total replacement of stapes

4. Tinnitus – ringing of ears from impacted wax, otitis media, loud noise, etc.

5. Types of hearing lossa. Conductive – sounds prevented from reaching inner earb. Sensorineural – problem with inner ear and auditory nerve

D. Disorders of the nose1. Rhinitis

a. Inflammation of lining of nose with congestion, drainageb. Cause – allergies, drugs, infection, odors, etc.c. Rx – eliminate cause, antihistamine

Summer 2005 L.5

Unit L: Sensory System

Competency 1H12: Analyze the anatomy and physiology of the special senses.

Materials/Resources

Scott, Ann Senisi and Elizabeth Fong. Body Structures & Functions. Delmar Publishers, Current Edition. www.DelmarAlliedHealth.com

National HOSA Handbook: Section B. Published by HOSA, Flower Mound, Texas. Current Edition. www.hosa.org

Teaching/Learning Indicators: The following letters are used to indicate specific skills/areas required in the instructional activity.

R Reading SS Social StudiesW Writing S ScienceM Math A The ArtsH Health professional/parent/community involvement

Summer 2005 L.6

Objective 1H12.01 Explain the structure of the eye.

Teaching/Learning Activities

Cognitive S, AUsing the resource Body Structures and Functions as a guide, have students draw, color and label the parts of the eye.

Basic Skills S, RHave students read the chapter on the Sensory System in Body Structures and Functions and answer the questions at the end of the chapter.

Technology SHave students utilize the AP challenge disc included in Body Structures and Functions.

Employability S, HInvite a health professional who works on an organ procurement team to discuss the process of corneal transplants. Have the students write 5-10 facts they learned from the presentation.

Critical Thinking SStudents are to complete the worksheet “I See What Doesn’t Belong.” (Appendix 1H12.01B)

Special NeedsEach student will reach the highest level of mastery in the least restrictive environment as recommended in the student’s IEP.

Summer 2005 L.7

Objective 1H12.02 Analyze the function of the eye.

Teaching/Learning Activities

Cognitive SHave students complete the “Eye Function” chart. (Appendix 1H12.02A)

Teamwork SHave students work in pairs to “look at eyes” and answer the questions in Appendix 1H12.02B.

*If students are uncomfortable with others looking at their eyes, allow them to use individual mirrors.

Critical Thinking SUsing index cards labeled with the structures of the eye, have students arrange themselves as the pathway of vision. (Each student “plays” the role of a part such as pupil, cornea, etc.)

Teamwork S, HInvite an optometrist to class to talk about the function of the eye.

Special NeedsEach student will reach the highest level of mastery in the least restrictive environment as recommended in the student’s IEP.

Summer 2005 L.8

Objective 1H12.03 Explain the structure and function of the ear, nose, and tongue.

Teaching/Learning Activities

Cognitive SHave students label the diagram of the ear. (Appendix 1H12.03A)

Critical Thinking SHave each student make an index card with the terminology related to the ear (Appendix 1H12.01A), and the definition on the reverse:

Have students line the cards in the proper order to illustrate the pathway of hearing.

Technology SStudents will use the A & P Challenge Disc available from Body Structures and

Functions.

Critical Thinking SFollowing a teacher-led discussion of the functions of the sense of smell and taste, have students participate in the following “Tell by Taste” activity.

Peel and cut foods into cubes (enough for all students). Supplies needed: Blindfold, nose clip or student pinches nose, apple, potato, lemon, onion, cheese, chocolate, toothpicks, cups, and water. Using a toothpick, rub a food cube on the tongue for 5 seconds. Ask the taster to identify the food. Rinse mouth with water. Try other foods in the same manner.

Then try foods without nose clip or pinching. Is the identification easier?

Critical Thinking S, WTake students outside and have them stand quietly for 2 to 3 minutes. Bring them

back into the classroom and ask them to write their answers to the following questions.

1. What did you hear?2. What did you smell?

Take students outside again and have them stand quietly for 2 to 3 minutes. Bring them back into the classroom and ask the questions again. Compare the results.

Employability Skills S, H, WInvite a school nurse or audiologist to class to discuss the sense of hearing. Have students complete the KWL chart (Appendix 1H12.03B)

Technology SShow the video series “Mystery of the Senses.” (Ordering information contained in the appendix of this unit.)

Special NeedsEach student will reach the highest level of mastery in the least restrictive environment

Summer 2005 L.9

as recommended in the student’s IEP.

Summer 2005 L.10

Objective 1H12.04 Identify characteristics and treatment of common sensory disorders.

Teaching/Learning Activities

Critical Thinking S, WHave students go to the media center to research otitis media and write a one page summary of their findings. Compare the statistics and developments in recent years. Are there more cases of the disease now, and if so, why?

Critical Thinking SAllow students the opportunity to write without seeing. Have students write numbers 1 to 10. Then have students close their eyes and write 1 to 10 again. Have studentscompare the two writings. Are the writings evenly spaced, sized, and shaped as the first set? How frustrating was it to write without sight?

Employability Skills S, HInvite a spokesperson from the local association for the blind to explain the “Braille System.” Another alternative is to contact someone connected with the school system who has responsibilities with teaching the visually impaired.

Teamwork S, MDivide students into teams and have them do a survey indicating how many studentshave had or know someone who has had a disorder/disease of the ear or eye. Includeotitis media, glaucoma, cataracts, conjunctivitis, vertigo, wear glasses, or contacts. After obtaining the results of the surveys, have students divide the responses into age groups to determine if there is a correlation between age and the diseases. Students should prepare the information obtained in percentages and may design graphs depicting the results.

HOSA S, WUsing the HOSA guidelines for Researched Persuasive Speaking, have students write a persuasive speech on the topic, “To Tube My Child’s Ears or Not to Tube My Child’s Ears.” Students will probably need to research the controversy surrounding this topic prior to writing.

Cognitive SAllow students to do vision screening using the Snellen Eye Chart to determine if anyone suffers from myopia. Then have students discuss what has happened to the pathway of vision to create this problem.

Critical Thinking S, WHave students work in small groups to draw conclusions about the “Medical Case Studies for the Sensory System.” (Appendix 1H12.04A)

Special NeedsEach student will reach the highest level of mastery in the least restrictive environment as recommended in the student’s IEP.

Summer 2005 L.11

Unit L: Sensory SystemTerminology List

Summer 2005 L.12

Eye

1. accommodation2. anterior chamber3. aqueous humor4. choroid coat5. cones6. conjunctiva7. constrict 8. cornea9. dilate10. extrinsic muscles11. intrinsic muscles12. iris13. lacrimal glands14. lens15. optic disc16. optic nerve17. orbital cavity18. posterior chamber19. pupil20. retina21. rods22. sclera

23. vitreous humorEar

1. auricle2. cerumen3. cochlea4. Eustachian tube5. external auditory canal6. incus7. malleus8. organ of Corti9. pathway of hearing10. pinna11. semicircular canals12. stapes13. tympanic membrane

Nose/Tongue

1. olfactory nerve2. papillae3. taste buds

Summer 2005 L.13

Disorders and Related Terminology

1. astigmatism2. cataracts3. color blindness4. conductive hearing loss5. conjunctivitis6. deafness7. epistaxis8. glaucoma9. hordeolum10. hyperopia

11. myopia12. ophthalmoscope13. otitis media14. presbyopia15. rhinitis16. sensorineural hearing loss17. Snellen eye chart18. sty19. vertigo

Appendix 1H12.01A

Summer 2005 L.14

I See What Doesn’t Belong

Students are to circle the word that doesn’t belong and write why it doesn’t fit with the other words.

1. outer white sclera retina

2. cornea sclera inner window of the eye

3. retina aqueous optic disc blind spot

4. cornea pupil iris intrinsic muscles

5. green iris pupil blue

6. retina rods cones choroid

7. lacrimal glands conjunctiva orbital cavity vitreous humor

8. posterior jelly-like aqueous humor vitreous humor

9. pupil crystalline disc-shaped lens

10. constrict dilate lens pupil

1.____________________________________________________________________

2.____________________________________________________________________

3.____________________________________________________________________

4.____________________________________________________________________

5.____________________________________________________________________

6.____________________________________________________________________

7.____________________________________________________________________

8.____________________________________________________________________

9.____________________________________________________________________

10.___________________________________________________________________

Appendix 1H12.01B

Summer 2005 L.15

Eye Function Chart

Complete the following chart, describing the function of each part of the eye – and related terms.

Structure/Term Function

Sclera

Cornea

Choroid coat

Pupil

Iris

Lens

Aqueous humor

Vitreous humor

Retina

Rods

Cones

Optic disc

Appendix 1H12.02A

Summer 2005 L.16

Name _____________________________________________________ Date ___________

Look Into My Eyes

You are to work with your partner to “look at eyes” and answer the following questions:

Please wash your hands before beginning this activity.

1. Are the irises exactly the same color? Yes or No? Describe:____________________________________________________________________________________________________________________________________

2. Can you see the conjunctiva? Yes or No

3. Can you see into the pupil? Yes or No

3. Pull down the lower eyelid gently to see the lacrimal ducts.

4. Using a pen light, look at the pupils constrict and dilate. How and why do the pupils control the amount of light that enters the eye?______________________________________________________________________________________________________________________________________________________________________________________________________

5. Complete the activity on p. 145 of Body Structures and Functions to understand the “blind spot.” Describe what you did and saw:______________________________________________________________________________________________________________________________________________________________________________________________________

6. Using an ophthalmoscope, look at the red reflex of the eye and describe what you saw:______________________________________________________________________________________________________________________________________________________________________________________________________

Appendix 1H12.02B

Summer 2005 L.17

The Ear

Label the following structures of the ear:

Auricle External auditory meatus MalleusIncus Stapes Tympanic membraneSemicircular canals Cochlea Eustachian tubePinna

Appendix 1H12.03A

Summer 2005 L.18

KWL

Directions: Before the speaker arrives to class, complete the first two columns of the chart below. After the speaker’s discussion, complete the third column.

Speaker’s Name _________________________________________________

Profession _________________________________________________

What I Know What I Want to Know What I Learned

Appendix 1H12.03B

Summer 2005 L.19

Medical Case Studies for the Sensory System

1. Mrs. Cloud, age 30, went to visit her doctor one sunny spring day. She was very concerned because she had noticed a loss of hearing which had gradually gotten worse. When the doctor asked about her family history, Mrs. Cloud mentioned that her mother and aunt also suffered from hearing loss. After examining the patient, the doctor diagnosed her with a disorder, in which bony changes prevent the stapes from vibrating normally. The name of this disorder is __________________________.

He recommended surgery for Mrs. Cloud to replace the stapes. What is this surgical procedure called? ___________________________

2. Megan was running late and forgot her towels. After the basketball game when she took a shower, she borrowed Christina’s towel. Later that night when they went our for pizza, she noticed Christina rubbing her eyes. They seem be watering a lot and were very red. About three days later, when Megan’s alarm went off, she could not open her left eye It was swollen and a thick mucous discharge had formed a crust over her eyelid. Her eyes burned and itched. What did the doctor diagnose Megan with? ____________________

What instructions do you think he gave Megan and her mother to prevent it from spreading to other family members? ______________ ___________________________

3. Mrs. Osborne took her baby to the pediatrician because he had cried most of the night and kept holding the left side of his head. She reported he had had a cold for about a week. After looking at his ear with an __________________, the doctor reported the baby had a bulging red eardrum. She thought the cause was a middle ear infection. She told the mother the baby was suffering from ________________________________________.

The pediatrician ordered antibiotics, but because the infection was so bad, it was necessary to cut the eardrum so it would not rupture. What procedure did the doctor do? ______________________

4. Becky has had to do a lot of reading for school. She had never had vision problems before, but lately she was having trouble reading the print in the book. She found herself having to hold the book further away from her eyes. She also had trouble reading the instructions on the back of medication bottles. What condition did the doctor diagnose Becky with? __________ ________________________________________

Summer 2005 L.20

What treatment did she probably order for Becky? ______________________________

5. Mrs. Rohan, age 72, comes to the physician office complaining of fuzzy vision lately. After examining her, the doctor asked her how long she had had those white patches on her lenses. What is her problem? __________________________________________

What treatment will the physician probably prescribe? ___________________________

6. Chris is referred to the eye clinic by the school nurse who suspects he needs glasses. Upon examination, it is determined that Chris is myopic. Will he need concave or convex lenses? _________________________________________.

Explain your answer:

7. Mrs. Dancy cannot sleep at night because her husband’s snoring keeps her awake. She is also alarmed because he has had several bad nose bleeds lately and has complained of headaches. She insists that he go to the doctor. What did her husband tell her was wrong with him when he returned home from seeing the physician? ______________________________________.

He tells her about a new treatment for this condition. What is this treatment and how is it used? ____________________________________________

8. One minute Judy was enjoying the party, and the next she was overcome with severe dizziness and nausea. She barely made it to the bathroom where she vomited a large amount of pea green fluid. She thought she had the flu and stayed in bed for three days until the dizziness had passed. Two weeks later she had an identical attack and this time she noted a ringing in her ears. Frightened she went to the emergency room. What diagnosis was made of Judy? __________________________

What did the physician tell her was the cause of the problem? ______________________________________________________________________

9. During a pick-up softball game, Monica got hit in the nose catching a fly ball. She lost her sense of smell temporarily. How would you explain this injury to Monica and her mother? ______________________________________________________________________

10. Paul notices that every time lately that he gets a sore throat, he also has an ear ache. Paul does not understand how the two signs could be related. How would you explain this to Paul? ____________________________________________________________________________________________________________________________________________

Summer 2005 L.21

Appendix 1H12.04A

Instructor Information

A great tool to help teach the sensory system diseases is a little kit called - Chronic Care Challenges. It comes with glasses that students can put on and experience what people with glaucoma, macular degeneration, cataracts, etc. It also has a tape and activities so the student can experience various diseases related to hearing. The kit cost less than $50.00 and comes with lesson plans. It can be purchased from NASCO or:

Chronic Care Challenges Inc.PO Box 47632Wichita, KS 67201 - 7632

Phone: 316-634-6845Fax: 316 - 634-1554

Email @ chroniccare.com

PS: It is an excellent resource for Health Team Relations also for their unit on disabilities.

Summer 2005 L.22

Instructor Information

NOVA Home Videos

To order call 1-800-949-8670 or visit the web site at http://www.pbs.org/wgbh/shop/novavideohomesubj.html.

This information is provided for review by Health Occupations Education teachers. The inclusion of this source does not constitute endorsement by the Department of Public Instruction. Teachers are reminded to follow local Board of Education policies related to the use of media in the classroom.

MIND AND BODY Home Videos ComaRacing to New York Hospital, a doctor relays urgent instructions to the ER where a child, hit by a car, lies unconscious. In a gripping real-life drama, NOVA follows famous neurosurgeon Jam Ghajar as he struggles to save a boy with massive head trauma, using simple but crucial techniques that are dangerously absent from most hospitals across the country. 1 hr. $19.95 WG2411

Ebola: The Plague Fighters

Travel for the first time ever past the quarantine line for a close-up look at the recent Ebola outbreak in Zaire, Africa, and the battle to contain it. 1 hr. $19.95 WG2304

Life's First FeelingsGlimpse inside the world of infants' personality traits, emotional reactions, and social interactions. 1 hr. $19.95 WG9304

MD: The Making of A DoctorCheck up on seven aspiring doctors as they undergo the exhilarating and grueling years of

medical training.2 hrs. $19.95 WG2207

Mystery of the Senses

5-part series inspired by Diane Ackerman's bestseller A Natural History of the Senses.5 videos, 1 hr. each, $69.95 WG2214

Hearing 1 hr. $19.95 WG2209Smell 1 hr. $19.95 WG2210Taste 1 hr. $19.95 WG2211Touch 1 hr. $19.95 WG2212Vision 1 hr. $19.95 WG2213

Summer 2005 L.23

The Miracle of LifeRide along with an incredible microphotographic voyage through the body as a new life begins, including the moment of conception. 1 hr. $19.95 WG001

Odyssey of Life3 video set $49.95 WGB2317

The Ultimate JourneyFrom the maker of The Miracle of Life comes another astounding glimpse into the mysteries of life before birth. Stunning microphotography by Lennart Nilsson shows how the developing human embryo reveals links to other species--reflecting a shared ancestry that harks back to the dawn of creation. 1 hr. $19.95 WG2317

The Unknown WorldThey're hiding in your closet. They're lurking in your bed. They're all over you--and now, thanks to the microphotography of Lennart Nilsson (The Miracle of Life), you can catch these creepy crawlers in the act, magnified to monster size. 1 hr. $19.95 WG2318

The Photographer's SecretsFor the first time ever, Lennart Nilsson--the photographer who led us into the awe-inspiring world of the womb--reveals the secret state-of-the-art techniques that gave us The Miracle of Life and much more. 1 hr. $19.95 WG2319

Siamese TwinsObserve the intricate plans and operations that give independence to two young girls.

1 hr. $19.95 WG2204

The Universe WithinTravel along for an incredible visual tour inside the human body with micro-photography and computer animation achieved by the creators of The Miracle of Life. 1 hr. $19.95 WG2206A

What's New About MenopauseExamine new research and medical capabilities that stir up ethical controversies surrounding the

ability to postpone menopause or bear children after "the change." 1 hr. $19.95 WG2114

The Wonder of Life Gift Set

Hidden from the human eye, the wonder of life unfolds in, on and around us with startling beauty and unexpected drama. And now, for the first time, you can enter this unseen world, thanks to the stunning microphotography of Lennart Nilsson. Titles: The Ultimate Journey, The Unknown World, The Photographer's Secrets, and The Miracle of Life.4 videos, 1 hr. each, $59.95 WG177

Summer 2005 L.24

Human BodyThe intricate wonders of the human body are revealed in extraordinary visual detail. $49.95 WG085

The Miracle of Life Take an incredible microphotographic voyage through the body as a new life begins, from

conception to birth. 1 hr.

The Universe WithinGet an inside look at armies of infection fighters, the journey of a peanut butter and jelly sandwich, and the power of an athlete's muscles. 1 hr.

The Ultimate JourneyExplore life's origins as you examine both the differences between and the uncanny similarities of the fetal development of humans and animals. 1 hr.

The Doctors See how doctors operate behind the scenes. Grades 7 and up. $49.95 WG104 MD: The Making of a Doctor 2 hrs.

Ebola: The Plague Fighters 1 hr.

Summer 2005 L.25

Unit L: Sensory System

OVERHEAD TRANSPARENCYMASTERS

Summer 2005 L.26

The Eye 1” in diameter Protected by orbital socket of

skull, eyebrows, eyelashes and eyelids

Bathed in fluid from LACRIMAL GLANDS – tears empty into nasal cavity

CONJUNCTIVA – thin membrane that lines the eyelids and covers part of the eye, secretes mucous to lubricate eye

Wall of the eye made up of three coats

SCLERA Outer layer White of the eye Tough coating, helps maintain shape of

eye and protects what’s inside Muscles responsible for moving the eye are

attached to the sclera – called EXTRINSIC MUSCLES

Summer 2005 L.27

CORNEA Front of sclera – clear part (no blood vessels) Transparent so light rays can pass through Gets O2 and nutrients through lymph

CHOROID COAT Middle layer Contains blood vessels Opening in front is the PUPIL Colored, muscular layer surrounding pupil is IRIS INTRINSIC MUSCLES – change size of iris to

control amount of light entering through the pupil

Summer 2005 L.28

LENS Crystalline structure located behind iris and pupil Elastic, disc-shaped, biconvex Situated between the anterior and posterior

chambers ACCOMMODATION – change in the shape of the

lens to allow for near and distant vision ANTERIOR CHAMBER filled with AQUEOUS

HUMOR, a watery fluid. POSTERIOR CHAMBER filled with transparent,

jellylike substance – VITREOUS HUMOR

RETINA Innermost layer Light rays focus an image on the retina The image travels to the cerebral cortex via the

OPTIC NERVE If light rays don’t focus properly on the retina,

corrective lenses can bend the light rays as required.

Retina contains specialized cells – rods and cones RODS – sensitive to dim light CONES – sensitive to bright light and color

Summer 2005 L.29

OPTIC DISC – on the retina, known as the blind spot – nerve fibers gather here to form the optic nerve, no rods or cones

Pathway of Vision

Summer 2005 L.30

Cornea

Pupil Lens (Where light rays are refracted)

RetinaRR

Rods and Cones (pick up stimulus)

Optic Nerve

The Ear

Hearing and equilibrium3 parts: Outer, middle and inner ear

Outer EarPINNA (AURICLE) – outer ear, collects sound wavesEXTERNAL AUDITORY CANAL – ear canalCERUMEN – earwax, protects the earTYMPANIC MEMBRANE – ear drum, separates outer and middle ear

Middle Ear

Summer 2005 L.31

Cavity in temporal bone Connects with pharynx by EUSTACHIAN TUBE –

which equalizes pressure in the middle ear with outside atmosphere

Bones in middle ear that transmit sound waves from ear drum to inner ear1.MALLEUS (hammer)2.INCUS (anvil)3.STAPES (stirrup)

Inner Ear

Contains spiral shaped organ of hearing – the COCHLEA

The cochlea contains a membranous tube, the cochlear duct – which is filled with fluid that vibrates when sound waves are transmitted by the stapes

ORGAN OF CORTI – delicate hairlike cells that pick up vibrations of fluid and transmit them as a sensory impulse along the auditory nerve to the brain

SEMICIRCULAR CANALS – three structures in the inner ear, contain liquid that is set in motion by head and body movements – impulses sent to cerebellum to help maintain body balance (equilibrium).

Summer 2005 L.32

Pathway of Hearing

Summer 2005 L.33

External Auditory Canal

Tympanic Membrane

Ossicles (malleus, incus & stapes)

Cochlea

Auditory nerve

The Nose Smell accounts for 90% of taste Tissue in the nose, olfactory epithelium, contains

specialized nerve cell receptors. Those receptors stimulate the OLFACTORY

NERVE to the brain.

The Tongue

Mass of muscle tissue

Bumps on the surface are PAPILLAE, they contain the TASTE BUDS

Receptors in taste buds send stimuli through 3 cranial nerves to the cerebral cortex

Summer 2005 L.34

Disorders of the Eye

CONJUCTIVITIS Pink eye Inflammation of conjunctival membranes in front of

the eye Redness, pain, swelling and discharge Highly contagious Rx – antibiotic eye drops

GLAUCOMA Excessive intraocular pressure causing destruction

of the retina and atrophy of the optic nerve Caused by overproduction of aqueous humor, lack

of drainage, or aging Symps – develop gradually – mild aching, loss of

peripheral vision, halo around the light TONOMETER – measures intraocular pressure Rx – drugs or laser surgery

Summer 2005 L.35

CATARACTS Lens of eye gradually becomes cloudy Frequently occurs in people over 70 Causes a painful, gradual blurring and loss of

vision Pupil turns from black to milky white Rx – surgical removal of the lens

STY (HORDEOLUM) Abscess at the base of an eyelash (in sebaceous

gland) Symps – red, painful and swollen Rx – warm, wet compresses

Vision Defects

PRESBYOPIA Lens loses elasticity, can’t focus on close or

distant objects Usually occurs after age 40 Rx - Bifocals

HYPEROPIA Farsighted Focal point beyond the retina because eyeball too

short Convex lenses help

Summer 2005 L.36

MYOPIA Nearsighted Eyeball too long Concave lenses help

ASTIGMATISM Irregular curvature of the cornea or lens, causing

blurred vision and eye strain Rx – corrective lenses

OPHTHALMOSCOPE – instrument for viewing inside the eye

SNELLEN EYE CHART – chart that uses letters or symbols in calibrated heights to check for vision defects

Summer 2005 L.37

Disorders of the EarLoud noise and hearing loss – hearing is fragile. Loud noise over a period of time can cause hearing loss. (Deafness)

OTITIS MEDIA Infection of the middle ear Often a complication of a common cold in

children Rx – antibiotics If chronic or if fluid builds up – MYRINGOTOMY

(opening in the tympanic membrane) with tubes inserted will relieve the pressure

Disorders of the NoseRHINITIS Inflammation of the lining of the nose with nasal

congestion, drainage, sneezing and itching Caused by allergies, infection, fumes, odors,

emotion, or drugs Rx – eliminate causes, antihistamines

Summer 2005 L.38