Chapter 12 Somatic and Special Senses
Receptor Types <ul><li>Chemoreceptors </li></ul><ul><ul><li>respond to changes in chemical concentrations </li></ul></ul><...
Sensory Adaptation <ul><li>adjustment of sensory receptors from continuous stimulation </li></ul><ul><li>stronger stimulus...
Touch and Pressure Senses <ul><li>Free nerve endings </li></ul><ul><ul><li>common in epithelial tissues </li></ul></ul><ul...
Touch and Pressure Senses <ul><li>Meissner’s corpuscles </li></ul><ul><ul><li>abundant in hairless  portions of skin </li>...
Touch and Pressure Senses <ul><li>Pacinian corpuscles </li></ul><ul><ul><li>common in deeper subcutaneous tissues, tendons...
Temperature Senses <ul><li>Warm receptors </li></ul><ul><ul><li>sensitive to temperatures above 25 o C (77 o  F) </li></ul...
Sense of Pain <ul><li>free nerve endings  </li></ul><ul><li>widely distributed  </li></ul><ul><li>nervous tissue of brain ...
Referred Pain <ul><li>may occur due to sensory impulses from two regions following a common nerve pathway to brain  </li><...
Special Senses <ul><li>smell  in olfactory organs </li></ul><ul><ul><li># 1 </li></ul></ul><ul><li>taste  in taste buds </...
Olfactory Receptors
Smell <ul><li>Olfactory Receptors </li></ul><ul><ul><li>chemoreceptors </li></ul></ul><ul><ul><li>respond to chemicals dis...
Taste <ul><li>Taste Buds </li></ul><ul><ul><li>organs of taste </li></ul></ul><ul><ul><li>located on papillae of tongue, r...
Taste Receptors Cranial nerves 7, 9 & 10
Taste Sensations <ul><li>Four Primary Taste Sensations </li></ul><ul><ul><li>sweet  – stimulated by carbohydrates </li></u...
Hearing Ear – organ of hearing <ul><li>3 Sections </li></ul><ul><ul><li>External </li></ul></ul><ul><ul><li>Middle </li></...
External Ear <ul><li>pinna </li></ul><ul><ul><li>collects sounds waves </li></ul></ul><ul><li>outer ear canal </li></ul><u...
Middle Ear <ul><li>auditory ossicles </li></ul><ul><ul><li>vibrate in response to tympanic membrane </li></ul></ul><ul><ul...
Auditory Tube <ul><li>eustachian tube   </li></ul><ul><li>connects middle ear to throat </li></ul><ul><li>helps maintain e...
Inner Ear <ul><li>complex system of labyrinths </li></ul><ul><li>osseous labyrinth   </li></ul><ul><ul><li>bony canal in t...
Inner Ear <ul><li>Parts of Inner Ear </li></ul><ul><ul><li>cochlea </li></ul></ul><ul><ul><ul><li>functions in hearing </l...
Semicircular Canals <ul><li>balance  </li></ul><ul><li>three canals at right angles </li></ul><ul><li>rapid turns of head ...
Sight <ul><li>Visual Accessory Organs </li></ul><ul><ul><li>eyelids </li></ul></ul><ul><ul><li>lacrimal apparatus </li></u...
Eyelid <ul><li>composed of four layers </li></ul><ul><ul><li>skin </li></ul></ul><ul><ul><li>muscle  </li></ul></ul><ul><u...
Lacrimal Apparatus <ul><li>lacrimal gland </li></ul><ul><ul><li>lateral to eye </li></ul></ul><ul><ul><li>secretes tears <...
Extrinsic Eye Muscles <ul><li>Superior rectus </li></ul><ul><ul><li>rotates eye up and medially </li></ul></ul><ul><li>Inf...
Extrinsic Eye Muscles <ul><li>Lateral rectus </li></ul><ul><ul><li>rotates eye laterally </li></ul></ul><ul><ul><li>*Abduc...
Outer Eye <ul><li>Cornea </li></ul><ul><ul><li>anterior portion </li></ul></ul><ul><ul><li>transparent </li></ul></ul><ul>...
Middle Tunic <ul><li>Ciliary body </li></ul><ul><ul><li>holds lens </li></ul></ul><ul><ul><li>moves lens for focusing </li...
Lens <ul><li>transparent </li></ul><ul><li>biconvex </li></ul><ul><li>lies behind iris </li></ul><ul><li>elastic!!! </li><...
Accommodation <ul><li>changing of lens shape to view objects </li></ul>
Iris <ul><li>composed of connective tissue and smooth muscle </li></ul><ul><li>pupil  is hole in iris </li></ul><ul><li>di...
Anterior Portion of Eye <ul><li>filled with  aqueous humor </li></ul><ul><li>maintains shape of anterior portion of eye </...
Inner Eye <ul><li>retina </li></ul><ul><ul><li>contains photoreceptors </li></ul></ul><ul><ul><li>continuous with optic ne...
Layers of Retina
Focusing On Retina <ul><li>as light enters eye, it is refracted by </li></ul><ul><ul><li>convex surface of cornea </li></u...
Clinical Application Refraction Disorders
Visual Pathway
Snellen Chart <ul><li>What does 20/40 or 20/100 mean? </li></ul>
Astigmatism Due to irregular shaped cornea Or Irregular curvature of the lens
Colorblindness <ul><li>Sex-linked trait; usually in males </li></ul><ul><li>Varying degrees of colorblindness </li></ul><u...
Cataracts <ul><li>From a cloudy lens; usually in older people </li></ul><ul><li>http://thedoctorstv.com/main/procedure_lis...
Corneal transplants <ul><li>Cornea disease is the leading cause of blindness </li></ul><ul><li>Restore sight with a transp...
Glaucoma <ul><li>Too much pressure in the eye </li></ul><ul><li>Leads to permanent damage of the optic nerve </li></ul><ul...
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12 sense organs

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12 sense organs

  1. 1. Chapter 12 Somatic and Special Senses
  2. 2. Receptor Types <ul><li>Chemoreceptors </li></ul><ul><ul><li>respond to changes in chemical concentrations </li></ul></ul><ul><li>Pain receptors </li></ul><ul><ul><li>respond to tissue damage </li></ul></ul><ul><li>Thermoreceptors </li></ul><ul><ul><li>respond to changes in temperature </li></ul></ul><ul><li>Mechanoreceptors </li></ul><ul><ul><li>respond to mechanical forces </li></ul></ul><ul><li>Photoreceptors </li></ul><ul><ul><li>respond to light </li></ul></ul>
  3. 3. Sensory Adaptation <ul><li>adjustment of sensory receptors from continuous stimulation </li></ul><ul><li>stronger stimulus required to activate receptors </li></ul><ul><li>smell receptors undergo sensory adaptation </li></ul>
  4. 4. Touch and Pressure Senses <ul><li>Free nerve endings </li></ul><ul><ul><li>common in epithelial tissues </li></ul></ul><ul><ul><li>detect touch and pressure </li></ul></ul>
  5. 5. Touch and Pressure Senses <ul><li>Meissner’s corpuscles </li></ul><ul><ul><li>abundant in hairless portions of skin </li></ul></ul><ul><ul><li>detect light touch </li></ul></ul>
  6. 6. Touch and Pressure Senses <ul><li>Pacinian corpuscles </li></ul><ul><ul><li>common in deeper subcutaneous tissues, tendons, and ligaments </li></ul></ul><ul><ul><li>detect heavy pressure </li></ul></ul>
  7. 7. Temperature Senses <ul><li>Warm receptors </li></ul><ul><ul><li>sensitive to temperatures above 25 o C (77 o F) </li></ul></ul><ul><ul><li>unresponsive to temperature above 45 o C (113 o F) </li></ul></ul><ul><li>Cold receptors </li></ul><ul><ul><li>sensitive to temperature between 10 o C (50 o F) and 20 o C (68 o F) </li></ul></ul><ul><li>Pain receptors </li></ul><ul><ul><li>respond to temperatures below 10 o C </li></ul></ul><ul><ul><li>respond to temperatures above 45 o C </li></ul></ul>
  8. 8. Sense of Pain <ul><li>free nerve endings </li></ul><ul><li>widely distributed </li></ul><ul><li>nervous tissue of brain lacks pain receptors </li></ul><ul><li>stimulated by tissue damage, chemical, mechanical forces, or extremes in temperature </li></ul><ul><li>Phantom Pain </li></ul>
  9. 9. Referred Pain <ul><li>may occur due to sensory impulses from two regions following a common nerve pathway to brain </li></ul>
  10. 10. Special Senses <ul><li>smell in olfactory organs </li></ul><ul><ul><li># 1 </li></ul></ul><ul><li>taste in taste buds </li></ul><ul><ul><li># 7,9 &10 </li></ul></ul><ul><li>hearing and equilibrium in ears </li></ul><ul><ul><li># 8 </li></ul></ul><ul><li>sight in eyes </li></ul><ul><ul><li># 2 (vision) </li></ul></ul><ul><ul><li># 3,4 & 6 (movement) </li></ul></ul>
  11. 11. Olfactory Receptors
  12. 12. Smell <ul><li>Olfactory Receptors </li></ul><ul><ul><li>chemoreceptors </li></ul></ul><ul><ul><li>respond to chemicals dissolved in liquids </li></ul></ul><ul><li>Olfactory Organs </li></ul><ul><ul><li>contain olfactory receptors and supporting epithelial cells </li></ul></ul><ul><ul><li>cover parts of nasal cavity, superior nasal conchae, and a portion of the nasal septum </li></ul></ul>
  13. 13. Taste <ul><li>Taste Buds </li></ul><ul><ul><li>organs of taste </li></ul></ul><ul><ul><li>located on papillae of tongue, roof of mouth, linings of cheeks and walls of pharynx </li></ul></ul><ul><li>Taste Receptors </li></ul><ul><ul><li>chemoreceptors </li></ul></ul><ul><ul><li>taste cells – modified epithelial cells that function as receptors </li></ul></ul><ul><ul><li>taste hairs –microvilli that protrude from taste cells; sensitive parts of taste cells </li></ul></ul>
  14. 14. Taste Receptors Cranial nerves 7, 9 & 10
  15. 15. Taste Sensations <ul><li>Four Primary Taste Sensations </li></ul><ul><ul><li>sweet – stimulated by carbohydrates </li></ul></ul><ul><ul><li>sour – stimulated by acids </li></ul></ul><ul><ul><li>salty – stimulated by salts </li></ul></ul><ul><ul><li>bitter – stimulated by many organic compound </li></ul></ul>Spicy foods activate pain receptors
  16. 16. Hearing Ear – organ of hearing <ul><li>3 Sections </li></ul><ul><ul><li>External </li></ul></ul><ul><ul><li>Middle </li></ul></ul><ul><ul><li>Inner </li></ul></ul>
  17. 17. External Ear <ul><li>pinna </li></ul><ul><ul><li>collects sounds waves </li></ul></ul><ul><li>outer ear canal </li></ul><ul><ul><li>aka ear canal </li></ul></ul><ul><ul><li>carries sound to tympanic membrane </li></ul></ul><ul><li>eardrum </li></ul><ul><ul><li>aka ear tympanic membrane </li></ul></ul><ul><ul><li>vibrates in response to sound waves </li></ul></ul>
  18. 18. Middle Ear <ul><li>auditory ossicles </li></ul><ul><ul><li>vibrate in response to tympanic membrane </li></ul></ul><ul><ul><li>malleus, incus, and stapes </li></ul></ul><ul><ul><li>aka hammer, anvil & stirrup </li></ul></ul><ul><li>oval window </li></ul><ul><ul><li>stapes (stirrup) vibrates against it to move fluids in inner ear </li></ul></ul>
  19. 19. Auditory Tube <ul><li>eustachian tube </li></ul><ul><li>connects middle ear to throat </li></ul><ul><li>helps maintain equal pressure on both sides of tympanic membrane </li></ul><ul><li>usually closed by valve-like flaps in throat </li></ul>
  20. 20. Inner Ear <ul><li>complex system of labyrinths </li></ul><ul><li>osseous labyrinth </li></ul><ul><ul><li>bony canal in temporal bone </li></ul></ul><ul><ul><li>filled with perilymph </li></ul></ul><ul><li>membranous labyrinth </li></ul><ul><ul><li>tube within osseous labyrinth </li></ul></ul><ul><ul><li>filled with endolymph </li></ul></ul>
  21. 21. Inner Ear <ul><li>Parts of Inner Ear </li></ul><ul><ul><li>cochlea </li></ul></ul><ul><ul><ul><li>functions in hearing </li></ul></ul></ul><ul><ul><ul><li>snail-shaped </li></ul></ul></ul><ul><ul><ul><li>Have hearing receptor cells (hair cells) that bend with different frequencies to generate a nerve impulse </li></ul></ul></ul><ul><ul><li>semicircular canals </li></ul></ul><ul><ul><ul><li>functions in equilibrium </li></ul></ul></ul><ul><ul><ul><li>fluid-filled </li></ul></ul></ul>
  22. 22. Semicircular Canals <ul><li>balance </li></ul><ul><li>three canals at right angles </li></ul><ul><li>rapid turns of head or body stimulate hair cells </li></ul>
  23. 23. Sight <ul><li>Visual Accessory Organs </li></ul><ul><ul><li>eyelids </li></ul></ul><ul><ul><li>lacrimal apparatus </li></ul></ul><ul><ul><li>extrinsic eye muscles </li></ul></ul>
  24. 24. Eyelid <ul><li>composed of four layers </li></ul><ul><ul><li>skin </li></ul></ul><ul><ul><li>muscle </li></ul></ul><ul><ul><li>connective tissue </li></ul></ul><ul><ul><li>conjunctiva </li></ul></ul><ul><li>orbicularis oculi - closes </li></ul><ul><li>levator palpebrae superioris – opens </li></ul><ul><li>tarsal glands – secrete oil onto eyelashes; so lids don’t stick </li></ul><ul><li>conjunctiva – mucous membrane; lines eyelid and covers portion of eyeball </li></ul>
  25. 25. Lacrimal Apparatus <ul><li>lacrimal gland </li></ul><ul><ul><li>lateral to eye </li></ul></ul><ul><ul><li>secretes tears </li></ul></ul><ul><li>canaliculi </li></ul><ul><ul><li>collect tears </li></ul></ul><ul><li>lacrimal sac </li></ul><ul><ul><li>collects from canaliculi </li></ul></ul><ul><li>nasolacrimal duct </li></ul><ul><ul><li>collects from lacrimal sac </li></ul></ul><ul><ul><li>empties tears into nasal cavity </li></ul></ul>
  26. 26. Extrinsic Eye Muscles <ul><li>Superior rectus </li></ul><ul><ul><li>rotates eye up and medially </li></ul></ul><ul><li>Inferior rectus </li></ul><ul><ul><li>rotates eye down and medially </li></ul></ul><ul><li>Medial rectus </li></ul><ul><ul><li>rotates eye medially </li></ul></ul>
  27. 27. Extrinsic Eye Muscles <ul><li>Lateral rectus </li></ul><ul><ul><li>rotates eye laterally </li></ul></ul><ul><ul><li>*Abducens Nerve VI </li></ul></ul><ul><li>Superior oblique </li></ul><ul><ul><li>rotates eye down and laterally </li></ul></ul><ul><ul><li>* Trochlear Nerve IV </li></ul></ul><ul><li>Inferior oblique </li></ul><ul><ul><li>rotates eye up and laterally </li></ul></ul>
  28. 28. Outer Eye <ul><li>Cornea </li></ul><ul><ul><li>anterior portion </li></ul></ul><ul><ul><li>transparent </li></ul></ul><ul><ul><li>light transmission </li></ul></ul><ul><ul><li>light refraction </li></ul></ul><ul><li>Sclera </li></ul><ul><ul><li>posterior portion </li></ul></ul><ul><ul><li>white of eye </li></ul></ul><ul><ul><li>protection </li></ul></ul>
  29. 29. Middle Tunic <ul><li>Ciliary body </li></ul><ul><ul><li>holds lens </li></ul></ul><ul><ul><li>moves lens for focusing </li></ul></ul><ul><li>Choroid coat </li></ul><ul><ul><li>provides blood supply </li></ul></ul><ul><ul><li>pigments absorb extra light </li></ul></ul>
  30. 30. Lens <ul><li>transparent </li></ul><ul><li>biconvex </li></ul><ul><li>lies behind iris </li></ul><ul><li>elastic!!! </li></ul><ul><li>held in place by suspensory ligaments </li></ul>
  31. 31. Accommodation <ul><li>changing of lens shape to view objects </li></ul>
  32. 32. Iris <ul><li>composed of connective tissue and smooth muscle </li></ul><ul><li>pupil is hole in iris </li></ul><ul><li>dim light stimulates radial muscles and pupil dilates </li></ul><ul><li>bright light stimulates c ircular muscles and pupil c onstricts </li></ul>
  33. 33. Anterior Portion of Eye <ul><li>filled with aqueous humor </li></ul><ul><li>maintains shape of anterior portion of eye </li></ul>
  34. 34. Inner Eye <ul><li>retina </li></ul><ul><ul><li>contains photoreceptors </li></ul></ul><ul><ul><li>continuous with optic nerve </li></ul></ul><ul><ul><li>rods provide vision in dim light </li></ul></ul><ul><ul><li>cones provide color vision </li></ul></ul><ul><li>optic disc – blind spot; contains no visual receptors; index card trick </li></ul><ul><li>vitreous humor – thick gel that holds retina flat against the back of the eye; gives eye round shape </li></ul>
  35. 35. Layers of Retina
  36. 36. Focusing On Retina <ul><li>as light enters eye, it is refracted by </li></ul><ul><ul><li>convex surface of cornea </li></ul></ul><ul><ul><li>convex surface of lens </li></ul></ul><ul><li>image focused on retina is upside down and reversed from left to right </li></ul>
  37. 37. Clinical Application Refraction Disorders
  38. 38. Visual Pathway
  39. 39. Snellen Chart <ul><li>What does 20/40 or 20/100 mean? </li></ul>
  40. 40. Astigmatism Due to irregular shaped cornea Or Irregular curvature of the lens
  41. 41. Colorblindness <ul><li>Sex-linked trait; usually in males </li></ul><ul><li>Varying degrees of colorblindness </li></ul><ul><li>Tests </li></ul>
  42. 42. Cataracts <ul><li>From a cloudy lens; usually in older people </li></ul><ul><li>http://thedoctorstv.com/main/procedure_list/59 Cataracts explained </li></ul><ul><li>http://thedoctorstv.com/main/procedure_list/58 Cataract surgery </li></ul>
  43. 43. Corneal transplants <ul><li>Cornea disease is the leading cause of blindness </li></ul><ul><li>Restore sight with a transplant </li></ul><ul><li>Central 2/3 of the cornea are replaced </li></ul><ul><li>Heals well; usually not rejected </li></ul>
  44. 44. Glaucoma <ul><li>Too much pressure in the eye </li></ul><ul><li>Leads to permanent damage of the optic nerve </li></ul><ul><li>Eventually leads to blindness (2 nd leading cause) </li></ul>

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