1. Sensory System Unit- L

2. Special Senses The Eye The Eye 1” in diameter 1” in diameter Protected by orbital socket of skull, eyebrows, eyelashes and eyelids. Protected by orbital socket of skull, eyebrows, eyelashes and eyelids. Bathed in fluid from Lacrimal Glands Bathed in fluid from Lacrimal Glands ( tears empty into nasal cavity) ( tears empty into nasal cavity) Conjunctiva – thin membrane that lines the eyelids and covers part of the eye. Conjunctiva – thin membrane that lines the eyelids and covers part of the eye.

3. Eyes 3.03 Remember the structures of the sensory system 3

4. The Eye Wall of Eye is made up of 3 layers or coats Wall of Eye is made up of 3 layers or coats Sclera, Choroid Coat, and the Retina Sclera, Choroid Coat, and the Retina SCLERA- Outer layer SCLERA- Outer layer White of the eye White of the eye Tough, fibrous capsule helps maintain shape of eye and protects the structure within. Tough, fibrous capsule helps maintain shape of eye and protects the structure within. EXTRINSIC MUSCLES- muscle responsible for moving the eye that are attached to the sclera. EXTRINSIC MUSCLES- muscle responsible for moving the eye that are attached to the sclera.

5. The Other Eye Cornea – Front of sclerotic coat (part of sclera) Cornea – Front of sclerotic coat (part of sclera) Clear part (no blood vessels) – called the “window of the eye” Clear part (no blood vessels) – called the “window of the eye” Transparent so light rays can pass through Transparent so light rays can pass through Gets O2 and nutrients through lymph Gets O2 and nutrients through lymph

6. I can see you…. Choroid Coat Choroid Coat Middle layer Middle layer Contains blood vessels Contains blood vessels Circular opening in front is the PUPIL Circular opening in front is the PUPIL Colored, muscular layer surrounding pupil is IRIS Colored, muscular layer surrounding pupil is IRIS INTRINSIC MUSCLES - change size of iris to control amount of light entering through the pupil – exposed to light = constriction INTRINSIC MUSCLES - change size of iris to control amount of light entering through the pupil – exposed to light = constriction

7. Can you see me?? Lens Lens Crystalline structure located behind iris and pupil – focuses light rays on retina – function is accommodation = adjusting for near / far vision Crystalline structure located behind iris and pupil – focuses light rays on retina – function is accommodation = adjusting for near / far vision Elastic, disc-shaped, biconvex Elastic, disc-shaped, biconvex Situated between the anterior and posterior chambers Situated between the anterior and posterior chambers

8. ANTERIOR CHAMBER filled with AQUEOUS HUMOR, a watery fluid. POSTERIOR CHAMBER filled with transparent, jellylike substance - VITREOUS HUMOR Both substances maintain eye’s spherical shape and refract light rays Hey…where did you go??

9. Oh no!! It’s dark in here!! Retina Retina Innermost layer – 3 rd coat of the eye – located between the posterior chamber and choroid coat Innermost layer – 3 rd coat of the eye – located between the posterior chamber and choroid coat Light rays focus an image on the retina Light rays focus an image on the retina The image then travels to the cerebral cortex via the OPTIC NERVE. The image then travels to the cerebral cortex via the OPTIC NERVE.  If light rays do not focus correctly on the retina, the condition may be corrected with properly fitted contact lenses, or eyeglasses, which bend the light rays as required.

10. Finally…the eye is almost over! Retina contains specialized cells, visual receptors - rods and cones Retina contains specialized cells, visual receptors - rods and cones RODS- sensitive to dim light…problems driving at night….damage to rods RODS- sensitive to dim light…problems driving at night….damage to rods CONES – sensitive to bright light – responsible for color vision CONES – sensitive to bright light – responsible for color vision OPTIC DISC- on the retina, known as the blind spot- nerve fibers gather here to form the optic nerve, no rods or cones. OPTIC DISC- on the retina, known as the blind spot- nerve fibers gather here to form the optic nerve, no rods or cones.

11. Posterior Vitreous Detachment My story… My story…

13. The Eye Pathway of Vision Pathway of Vision LIGHT RODS & CONES ( Pick up stimulus) OPTIC NERVE BRAIN CORNEAPUPIL LENS (Light rays are refracted) RETINA

14. The Ear Outer Ear PINNA (AURICLE)- outer ear, collects sound waves PINNA (AURICLE)- outer ear, collects sound waves EXTERNAL AUDITORY CANAL- ear canal EXTERNAL AUDITORY CANAL- ear canal CERUMEN- earwax, protects the ear CERUMEN- earwax, protects the ear TYMPANIC MEMBRANE- ear drum, separates outer and middle ear. TYMPANIC MEMBRANE- ear drum, separates outer and middle ear.

15. Can you hear me?? Middle Ear Middle Ear Cavity in temporal bone Cavity in temporal bone Connects with pharynx by EUSTACHIAN TUBE - which equalizes pressure in the middle ear with outside atmosphere. Connects with pharynx by EUSTACHIAN TUBE - which equalizes pressure in the middle ear with outside atmosphere. Bones in middle ear transmits sound waves from ear drum to inner ear. Bones in middle ear transmits sound waves from ear drum to inner ear. 1. MALLEUS (hammer) 2. INCUS (anvil) 3. STAPES (stirrup)

16. I can hear you I can hear you Inner Ear Inner Ear Contains spiral shaped organ of hearing - the COCHLEA 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. 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- in the cochlea - delicate hairlike cells that pick up vibrations of fluid and transmit them as a sensory impulse along the auditory nerve to the brain. ORGAN OF CORTI- in the cochlea - 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). 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).

18. Where does the sound go? Pathway of Hearing Pathway of Hearing Sound waves PinnaExternal Auditory CanalTympanic Membrane Ossicles ( malleus, incus, & stapes) CochleaAuditory nerveBrain Sound waves PinnaExternal Auditory CanalTympanic Membrane Ossicles ( malleus, incus, & stapes) CochleaAuditory nerveBrain

19. Understanding the functions of the ear Pathway of hearing Trace the pathway of hearing. Trace the pathway of hearing. Discuss the process of hearing. Discuss the process of hearing. What are decibels? What are decibels? 3.04 Understand the functions and disorders of the sensory system19

20. Decibel Unit used to measure the intensity of sound. Unit used to measure the intensity of sound.

21. The Nose & Tongue Nose Nose Smell accounts for 90% of taste Smell accounts for 90% of taste Tissue in the nose, olfactory epithelium, contains specialized nerve cell receptors. Tissue in the nose, olfactory epithelium, contains specialized nerve cell receptors. Those receptors stimulate the OLFACTORY NERVE to the brain. Those receptors stimulate the OLFACTORY NERVE to the brain. Tongue Tongue Mass of muscle tissue Mass of muscle tissue Bumps, projections, on the surface are papilla, they contain the TASTE BUDS. Bumps, projections, on the surface are papilla, they contain the TASTE BUDS. Receptors in the taste buds send stimuli through 3 cranial nerves to the cerebral cortex. Receptors in the taste buds send stimuli through 3 cranial nerves to the cerebral cortex.

22. Structures of the nose 3.03 Remember the structures of the sensory system 22

23. Structures of the nose 3.03 Remember the structures of the sensory system 23 Discuss the structures of the nose in relation to the olfactory nerve.

24. Trivia Tongue Did you know… Did you know… Taste is the weakest of the five senses Taste is the weakest of the five senses We have almost 10,000 taste buds inside our mouths; even on the roofs of our mouths We have almost 10,000 taste buds inside our mouths; even on the roofs of our mouths Everyone’s tongue print is different similar to fingerprints Everyone’s tongue print is different similar to fingerprints 3.03 Remember the structures of the sensory system 24

25. Structures of the tongue Taste receptors Taste receptors Also known as gustatory buds or taste buds Also known as gustatory buds or taste buds 3.03 Remember the structures of the sensory system 25 What type of tissue is the tongue made?

26. Common Sensory Disorders Disorders of the Eye Disorders of the Eye CONJUCTIVITIS CONJUCTIVITIS Pink eye Pink eye Inflammation of conjunctival membranes in front of the eye Inflammation of conjunctival membranes in front of the eye Redness, pain, swelling, and discharge Redness, pain, swelling, and discharge Highly contagious Highly contagious Rx- antibiotic eye drops Rx- antibiotic eye drops

27. Glaucoma Glaucoma Excessive intraocular pressure causing destruction of the retina and atrophy of the optic nerve Excessive intraocular pressure causing destruction of the retina and atrophy of the optic nerve Caused by over production of aqueous humor, lack of drainage, or aging. Caused by over production of aqueous humor, lack of drainage, or aging. Symps- develop gradually – mild aching, loss of peripheral vision, halo around the light Symps- develop gradually – mild aching, loss of peripheral vision, halo around the light TONOMETER- measures intraocular pressure TONOMETER- measures intraocular pressure Rx – drugs or laser surgery to decrease intraocular pressure Rx – drugs or laser surgery to decrease intraocular pressure Eye disorders

28. Eye Disorders Glaucoma: Glaucoma:

29. Common Sensory Disorders CATARACTS CATARACTS Lens of eye gradually becomes cloudy Lens of eye gradually becomes cloudy Frequently occurs in people over 70 Frequently occurs in people over 70 Causes a painful, gradual blurring and loss of vision Causes a painful, gradual blurring and loss of vision Pupil turns from black to milky white Pupil turns from black to milky white Rx- surgical removal of the lens Rx- surgical removal of the lens Macular Degeneration Macular Degeneration Eye disorder that occurs with aging Eye disorder that occurs with aging The macula ( part of the retina responsible for sharp color vision) degenerates The macula ( part of the retina responsible for sharp color vision) degenerates Vision is reduced but usually doesn’t cause total blindness. Vision is reduced but usually doesn’t cause total blindness.

30. Still problems with the eye Detached Retina Detached Retina May occur with aging- accident can cause it at younger age May occur with aging- accident can cause it at younger age Retina detaches from choroid Retina detaches from choroid Symps- loss of peripheral vision and then central vision Symps- loss of peripheral vision and then central vision Rx- laser or freezing technique Rx- laser or freezing technique STY ( HORDEOLUM) STY ( HORDEOLUM) Abscess at the base of an eyelash (in sebaceous gland) Abscess at the base of an eyelash (in sebaceous gland) Symps- red, painful and swollen Symps- red, painful and swollen Rx- warm, wet compresses Rx- warm, wet compresses

31. Eye Problems Sty: Sty:

32. Eye Injuries Tears are effective in cleaning the eye Tears are effective in cleaning the eye If glass or fragments get in eye, cover both eyes and see medical treatment. (DO NOT remove the object) If glass or fragments get in eye, cover both eyes and see medical treatment. (DO NOT remove the object) Night blindness = NYCTALOPIA- due to inactive rods Night blindness = NYCTALOPIA- due to inactive rods Color blindness- cones are affected – genetic disorder that carried by the female and transmitted to males. Color blindness- cones are affected – genetic disorder that carried by the female and transmitted to males.

33. Eye Injuries Color Blind Testing Color Blind Testing

34. Do you need glasses? PRESBYOPIA PRESBYOPIA Lens loses elasticity, cant focus on close or distant objects Lens loses elasticity, cant focus on close or distant objects Usually occurs after age 40 Usually occurs after age 40 Rx- bifocals Rx- bifocals HYPEROPIA HYPEROPIA Farsighted Farsighted Focal point beyond the retina because eyeball too short Focal point beyond the retina because eyeball too short Convex lenses help Convex lenses help MYOPIA MYOPIA Nearsighted – can’t see far away Nearsighted – can’t see far away Eyeball too long Eyeball too long Concave lenses help Concave lenses help Eye doctor = Opthamologist

35. Eye Problems Presbyopia: Presbyopia: Hyperopia: Hyperopia:

36. Eye Problems Myopia: Myopia:

37. Still more eye problems AMBLYOPIA AMBLYOPIA Reduction or dimness of vision Reduction or dimness of vision ASTIGMATISM ASTIGMATISM Irregular curvature of the cornea or lens, causing blurred vision and eye strain Irregular curvature of the cornea or lens, causing blurred vision and eye strain Rx- corrective lenses Rx- corrective lenses DIPLOPIA- double vision DIPLOPIA- double vision STABISMUS ( cross-eyes) STABISMUS ( cross-eyes) Eye muscles do not coordinate their actions Eye muscles do not coordinate their actions Usually in children Usually in children Rx – eye exercises or surgery Rx – eye exercises or surgery Opthalmoscope = used to examine the eye

38. Eye Problems Amblyopia: Amblyopia: Astigmatism: Astigmatism:

39. Eye Problems Diplopia: Diplopia:

40. Eye Problems Cross-eyed: Cross-eyed:

41. Disorders of the Ear Loud noise Hearing is fragile! Loud noise over a period of time can cause hearing loss. Symptoms- TINNITUS (ringing in ears) and difficulty understanding what people are saying Symptoms- TINNITUS (ringing in ears) and difficulty understanding what people are saying Conductive hearing loss….may be from excessive wax in ear canal Conductive hearing loss….may be from excessive wax in ear canal

42. Disorders of the Ear Sensorineural: damage to parts of the inner ear or auditory nerve that results in partial or complete deafness Sensorineural: damage to parts of the inner ear or auditory nerve that results in partial or complete deafness

43. Disorders of the Ear OTITIS MEDIA Infection of the middle ear Infection of the middle ear Often a complication of a common cold in children Often a complication of a common cold in children Rx- antibiotics Rx- antibiotics If chronic or if fluid builds up- MYRINGOTOMY (opening in the tympanic membrane) with tubes inserted will relieve the pressure. If chronic or if fluid builds up- MYRINGOTOMY (opening in the tympanic membrane) with tubes inserted will relieve the pressure. Sxs – fever, pain, fluid drainage Sxs – fever, pain, fluid drainage

44. Otitis Media

45. Other Sensory Problems Phantom Pain Phantom Pain After an amputation your brain still sends signals to amputated limb. Neural pathways are still intact. After an amputation your brain still sends signals to amputated limb. Neural pathways are still intact. Rhinorrhea Rhinorrhea Allergies cause constant, clear drainage from nose and down pharynx from maxillary sinuses. May cause chronic pharyngitis. Allergies cause constant, clear drainage from nose and down pharynx from maxillary sinuses. May cause chronic pharyngitis.

46. Other Sensory Problems Thrush (oral yeast infection characterized by white patches on tongue and cheeks) Antibiotics wipe out normal flora which allow fungi to flourish…vaginal and oral yeast infections are common with antibiotic use Antibiotics wipe out normal flora which allow fungi to flourish…vaginal and oral yeast infections are common with antibiotic use

47. Other Sensory Problems Thrush: Thrush: