A & p holes' senses ppt

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  • 1. Holes HumanAnatomy and Physiology Eleventh Edition Modified by Mrs. FiserShier 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 2112 1314 1522Pain, Touch 341 2256232 724 25827 26289 Taste102 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 ears3 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 brain5 6. Projection process in which the brain projects the sensationback to the apparent sourceit 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 Meissners corpuscles common in epithelial abundant in hairless portionstissuesof skin; lips simplest receptors detect fine touch; distinguish sense itchingbetween two points on the skin Pacinian corpuscles common in deeper subcutaneoustissues, tendons, and ligaments detect heavy pressure andvibrations8 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 painaching pain well localized difficult to pinpoint14 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 pain15 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 eyes16 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 nervesolfactory bulbsolfactory 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 afterstimulation20 21. Taste Buds organs of taste located on papillae of tongue, roof of mouth, linings ofcheeks and walls of pharynxEach 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 temporalbone filled with perilymph membranous labyrinth tube within osseouslabyrinth filled with endolymph 32 33. Three Parts of Labyrinths cochlea functions in hearing semicircular canals functions inequilibrium vestibule functions inequilibrium 33 34. Scala vestibuli upper compartment leads from oval window toapex of spiral part of bony labyrinthScala tympani lower compartment extends from apex of thecochlea to round window part of bony labyrinth34 35. CochleaCochlear duct portion of membranouslabyrinth in cochleaVestibular membrane separates cochlear ductfrom scala vestibuliBasilar membrane separates cochlear ductfrom scala tympani35 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 ismovement of head and not moving body40 41. Utricle communicates withsaccule andmembranous portion ofsemicircular canals Saccule communicates withcochlear duct Mucula hair cells of utricle andsaccule41 42. responds tochanges in headposition bending of hairsresults in generationof nerve impulse42 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 Ampullaris44 45. 10 11112213 14345156789 161718 45 46. The eye, the organ that contains the visualreceptors, provides vision with the assistance of :Visual Accessory Organs eyelids lacrimal apparatus extrinsic eye muscles46 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 cavity49 50. Superior rectus rotates eye up and mediallyInferior rectus rotates eye down and mediallyMedial rectus rotates eyemedially50 51. Lateral rectus rotates eye laterallySuperior oblique rotates eye down and laterallyInferior oblique rotates eye up andlaterally51 52. hollow spherical wall has 3 layers outer fibrous tunic middle vascular tunic inner nervous tunic52 53. Cornea anterior portion transparent light transmission light refractionSclera posterior portion opaque protection53 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 light54 55. filled with aqueous humor55 56. transparent biconvex lies behind iris largely composed oflens fibers elastic held in place bysuspensory ligamentsof ciliary body56 57. forms internal ring around front of eye ciliary processes radiating folds ciliary muscles contract and relax to move lens57 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 constricts59 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