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A & p holes' senses ppt

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  • 1. Hole’s Human Anatomy and Physiology Eleventh Edition Modified by Mrs. Fiser Shier  Butler  Lewis Chapter 10 Little BookCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1
  • 2. Smell 11 18 16 17 19 20 21 12 13 14 15 22 Pain, Touch 3 41 22 5 6 232 7 24 25 8 27 26 28 9 Taste 10 2
  • 3. General Senses • receptors that are widely distributed throughout the body • skin, various organs and jointsSpecial Senses • specialized receptors confined to structures in the head • eyes and ears 3
  • 4. Chemoreceptors • respond to changes in chemical concentrationsPain receptors (Nociceptors) • respond to tissue damageThermoreceptors • respond to changes in temperatureMechanoreceptors • respond to mechanical forces Photoreceptors • respond to light 4
  • 5. • stimulation of receptor causes local change in its receptor potential• a graded electrical current is generated that reflects intensity of stimulation• if receptor is part of a neuron, the membrane potential may generate anaction potential• if receptor is not part of a neuron, the receptor potential must betransferred to a neuron to trigger an action potential• peripheral nerves transmit impulses to CNS where they are analyzed andinterpreted in the brain 5
  • 6. Projection process in which the brain projects the sensationback to the apparent source it allows a person to pinpoint the region ofstimulation 6
  • 7. • ability to ignore unimportant stimuli (clothes)• involves a decreased response to a particular stimulusfrom the receptors (peripheral adaptations) or alongthe CNS pathways leading to the cerebral cortex(central adaptation)• sensory impulses become less frequent and may cease• stronger stimulus is required to trigger impulses 7
  • 8. Free nerve endings Meissner’s corpuscles • common in epithelial • abundant in hairless portions tissues of skin; lips • simplest receptors • detect fine touch; distinguish • sense itching between two points on the skin Pacinian corpuscles • common in deeper subcutaneous tissues, tendons, and ligaments • detect heavy pressure and vibrations 8
  • 9. Touch and Pressure Receptors 9
  • 10. Warm receptors • sensitive to temperatures above 25oC (77o F) • unresponsive to temperature above 45oC (113oF)Cold receptors • sensitive to temperature between 10oC (50oF) and 20oC (68oF) Pain receptors • respond to temperatures below 10oC • respond to temperatures above 45oC 10
  • 11. • free nerve endings• widely distributed• nervous tissue of brain lacks pain receptors• stimulated by tissue damage, chemical, mechanical forces,or extremes in temperature• adapt very little, if at all 11
  • 12. • pain receptors are the only receptors in viscera whose stimulation produces sensations• pain receptors respond differently to stimulation• not well localized• may feel as if coming from some other part of the body • known as referred pain 12
  • 13. • may occur due to sensory impulses from two regionsfollowing a common nerve pathway to brain 13
  • 14. Acute pain fibers Chronic pain fibers • A-delta fibers • C fibers •thin, myelinated •thin, unmyelinated • conduct impulses • conduct impulses more rapidly slowly • associated with • associated with dull, sharp pain aching pain • well localized • difficult to pinpoint 14
  • 15. Thalamus • allows person to be aware of pain Pain Inhibiting Substances • enkephalinsCerebral Cortex • serotonin • judges intensity of pain • endorphins • locates source of pain • produces emotional and motor responses to pain 15
  • 16. • sensory receptors are within large, complex sensoryorgans in the head• smell in olfactory organs• taste in taste buds• hearing and equilibrium in ears• sight in eyes 16
  • 17. Olfactory Receptors • chemoreceptors • respond to chemicals dissolved in liquidsOlfactory Organs • contain olfactory receptors and supporting epithelial cells • cover parts of nasal cavity, superior nasal conchae, and a portion of the nasal septum 17
  • 18. 18
  • 19. Once olfactory receptors are stimulated, nerve impulsestravel through • olfactory nerves olfactory bulbs olfactory tracts limbic system (for emotions) and olfactory cortex (for interpretation) 19
  • 20. • olfactory organs located high in the nasal cavityabove the usual pathway of inhaled air• olfactory receptors undergo sensory adaptationrapidly• sense of smell drops by 50% within a second afterstimulation 20
  • 21. Taste Buds • organs of taste • located on papillae of tongue, roof of mouth, linings of cheeks and walls of pharynx •Each has from 50-150 taste cells.Taste Receptors • chemoreceptors • taste cells – modified epithelial cells that function as receptors • taste hairs –microvilli that protrude from taste cells; sensitive parts of taste cells 21
  • 22. 22
  • 23. Five Primary Taste Sensations • sweet – stimulated by carbohydrates • sour – stimulated by acids • salty – stimulated by salts • bitter – stimulated by many organic compounds •umami- stimulated by certain amino acidsSpicy foods activate pain receptors 23
  • 24. Sensory impulses from taste receptors travel along • cranial nerves to • medulla oblongata to • thalamus to • gustatory cortex (for interpretation) 24
  • 25. 25
  • 26. 26
  • 27. 27
  • 28. Ear – organ of hearing Three Sections • External • Middle • Inner 28
  • 29. • auricle • collects sounds waves• external auditory meatus • lined with ceruminous glands • carries sound to tympanic membrane • terminates with tympanic membrane• tympanic membrane • vibrates in response to sound waves 29
  • 30. • tympanic cavity• air-filled space in temporalbone• auditory ossicles • vibrate in response to tympanic membrane • malleus, incus, and stapes• oval window • opening in wall of tympanic cavity • stapes vibrates against it to move fluids in inner ear 30
  • 31. • eustachian tube• connects middle ear tothroat• helps maintain equalpressure on both sidesof tympanic membrane• usually closed byvalve-like flaps inthroat 31
  • 32. • complex system of labyrinths• osseous labyrinth • bony canal in temporal bone • filled with perilymph• membranous labyrinth • tube within osseous labyrinth • filled with endolymph 32
  • 33. Three Parts of Labyrinths • cochlea • functions in hearing • semicircular canals • functions in equilibrium • vestibule • functions in equilibrium 33
  • 34. Scala vestibuli • upper compartment • leads from oval window to apex of spiral • part of bony labyrinthScala tympani • lower compartment • extends from apex of the cochlea to round window • part of bony labyrinth 34
  • 35. CochleaCochlear duct • portion of membranous labyrinth in cochleaVestibular membrane • separates cochlear duct from scala vestibuliBasilar membrane • separates cochlear duct from scala tympani 35
  • 36. Organ of Corti• group of hearing receptor cells(hair cells)• on upper surface of basilarmembrane• different frequencies of vibrationmove different parts of basilarmembrane• particular sound frequencies causehairs of receptor cells to bend• nerve impulse generated 36
  • 37. Organ of Corti 37
  • 38. 38
  • 39. 39
  • 40. Static Equilibrium Dynamic Equilibrium • vestibule • semicircular canals • sense position of • sense rotation and head when body is movement of head and not moving body 40
  • 41. • Utricle • communicates with saccule and membranous portion of semicircular canals• Saccule • communicates with cochlear duct• Mucula • hair cells of utricle and saccule 41
  • 42. • responds tochanges in headposition• bending of hairsresults in generationof nerve impulse 42
  • 43. • three canals at right angles• ampulla • swelling of membranous labyrinth that communicates with the vestibule• crista ampullaris • sensory organ of ampulla • hair cells and supporting cells • rapid turns of head or body stimulate hair cells 43
  • 44. Crista Ampullaris 44
  • 45. 10 111 122 13 14345 1567 8 9 16 17 18 45
  • 46. The eye, the organ that contains the visualreceptors, provides vision with the assistance of :Visual Accessory Organs • eyelids • lacrimal apparatus • extrinsic eye muscles 46
  • 47. They are housed within the orbital cavity,or orbit of the skull.Each orbit contains fat, blood vessels,nerves and connective tissue 47
  • 48. • palpebra• composed of four layers • skin • muscle • connective tissue • conjunctiva• orbicularis oculi - closes• levator palpebrae superioris –opens• tarsal glands – secrete oil ontoeyelashes• conjunctiva – mucousmembrane; lines eyelid andcovers portion of eyeball 48
  • 49. • lacrimal gland • lateral to eye • secretes tears• canaliculi • collect tears• lacrimal sac • collects from canaliculi• nasolacrimal duct • collects from lacrimal sac • empties tears into nasal cavity 49
  • 50. Superior rectus • rotates eye up and mediallyInferior rectus • rotates eye down and mediallyMedial rectus • rotates eye medially 50
  • 51. Lateral rectus • rotates eye laterallySuperior oblique • rotates eye down and laterallyInferior oblique • rotates eye up and laterally 51
  • 52. • hollow• spherical• wall has 3 layers • outer fibrous tunic • middle vascular tunic • inner nervous tunic 52
  • 53. Cornea • anterior portion • transparent • light transmission • light refractionSclera • posterior portion • opaque • protection 53
  • 54. Iris • anterior portion • pigmented • controls light intensityCiliary body • anterior portion • pigmented • holds lens • moves lens for focusingChoroid coat • provides blood supply • pigments absorb extra light 54
  • 55. • filled with aqueous humor 55
  • 56. • transparent• biconvex• lies behind iris• largely composed oflens fibers• elastic• held in place bysuspensory ligamentsof ciliary body 56
  • 57. • forms internal ring around front of eye• ciliary processes – radiating folds• ciliary muscles – contract and relax to move lens 57
  • 58. • changing of lens shape to view objects 58
  • 59. • composed of connectivetissue and smooth muscle• pupil is hole in iris• dim light stimulatesradial muscles and pupildilates• bright light stimulatescircular muscles andpupil constricts 59
  • 60. • fluid in anterior cavity of eye• secreted by epithelium on inner surface of the ciliary body• provides nutrients• maintains shape of anterior portion of eye• leaves cavity through canal of Schlemm 60
  • 61. • retina• contains visual receptors• continuous with optic nerve• ends just behind margin of the ciliary body• composed of several layers• macula lutea – yellowish spot in retina• fovea centralis – center of macula lutea; producessharpest vision• optic disc – blind spot; contains no visual receptors• vitreous humor – thick gel that holds retina flat againstchoroid coat 61
  • 62. • contains vitreous humor – thick gel that holds retinaflat against choroid coat 62
  • 63. • receptor cells, bipolar cells, and ganglion cells - providepathway for impulses triggered by photoreceptors to reach theoptic nerve• horizontal cells and amacrine cells – modify impulses 63
  • 64. 64
  • 65. Refraction • bending of light • occurs when light waves pass at an oblique angle into mediums of different densities 65
  • 66. Convex lenses cause Concave lenses causelight waves to converge light waves to diverge 66
  • 67. • as light enters eye, it is refracted by • convex surface of cornea • convex surface of lens• image focused on retina is upside down and reversed fromleft to right 67
  • 68. Rods Cones • long, thin projections • short, blunt projections • contain light sensitive • contain light sensitive pigment called rhodopsin pigments called • hundred times more erythrolabe, chlorolabe, sensitive to light than cones and cyanolabe • provide vision in dim light • provide vision in bright • produce colorless vision light • produce outlines of objects • produce sharp images • produce color vision 68
  • 69. Rods and Cones 69
  • 70. Rhodopsin Pigments on Cones • light-sensitive pigment in rods • each set contains different light- • decomposes in presence of sensitive pigment light • each set is sensitive to different • triggers a complex series of wavelengths reactions that initiate nerve • color perceived depends on impulses which sets of cones are stimulated • impulses travel along optic • erythrolabe – responds to red nerve • chlorolabe – responds to green • cyanolabe – responds to blue 70
  • 71. 71
  • 72. • provides perception of distance and depth• results from formation of two slightly different retinalimages 72
  • 73. 73
  • 74. Age related hearing loss due to • damage of hair cells in organ of Corti • degeneration of nerve pathways to the brain • tinnitusAge-related visual problems include • dry eyes • floaters (crystals in vitreous humor) • loss of elasticity of lens • glaucoma • cataracts • macular degeneration 74
  • 75. Refraction Disorders• concave lens corrects • convex lens correctsnearsightedness farsightedness 75