The Sense Organs

1. The Sense Organs

2. Special Senses • Taste • Smell • Vision • Hearing • Balance

3. Types of Receptors • Mechanoreceptors • Chemoreceptors • Thermoreceptors • Photoreceptors • Nociceptors (Pain Receptors)

4. Taste Taste and smell are involved with specific receptor cells called chemoreceptors  respond to chemicals in an aqueous solution food dissolved in saliva airborne chemicals dissolved in mucous membrane

5. The Tongue

6. Taste Buds Filiform papilla Fungiform papilla Circumvallate Papilla Tongue epithelium Connective tissue

7. taste pores taste buds papilla Taste Buds

8. Taste Buds

9. Five Basic Tastes Why are they important? Bitter- alkaloid Salty- metallic ions Sour- H+ Sweet- sugar Umami

10. Experiment Dry tongue with a paper towel and place a little sugar on surface. What do you taste?

11. Tastetriggers reflex involved in digestion; causes an increase of saliva in mouth (amylase) and gastric juice in stomach acids cause strong salivary reflex bad tasting food causes gagging or reflexive vomiting taste can change over time taste is 80% smell Mouth also contains: Thermoreceptors Mechanoreceptors Nociceptors- sensitive nerve fibers that are aware of painful stimuli

12. olfactory bulb bone olfactory receptor cell olfactory hairs Olfaction Nasal conchae

13. Olfaction Smell not as good as animals; however, some people are wine tasters, perfumers If you smell a particular odor all day, you won’t recognize its presence, you become accustomed, ex. garbage men Old people lose sense of smell- lots of perfume Humans can distinguish 10,000 or so chemicals What we really smell is pain: ex. chili, ammonia, menthol (cold) Specific chemicals cause specific patterns of neurons to fire

14. sclera tear drainage canal iris pupil The Eye cornea

15. Pupil

16. Lacrimal Apparatus

17. extrinsic eye muscles optic nerve The Eye

18. cornea sclera choroid iris retina pupil optic nerve lens aqueous humour vitreous humour

19. cornea iris lens aqueous humour pupil suspensory ligament canal of Schlemm ciliary body

20. Focusing the Image • Coarse Fixed Focusing • Cornea Shape • Accommodation- adjust configuration of • Lens Shape • Pupil Size

21. Properties of Light refraction

22. Accomodation Focusing on a Near Object

23. Accomodation Focusing on a Far Object

24. Vision & Corrective Lenses

25. Astigmatism

26. Astigmatism

27. Primary Visual Pathway

28. The Retina blind spot macula

29. photoreceptive cells light Details of the Retina Ganglion Amacrine Bipolar neuron Horizontal cells Choroid Schlera

30. Photoreceptive Cells of the Retina cone rod

31. Red-Green Color Blind Test

32. Illusions Effect: Subjective or illusory contours

33. Illusions Geometrical illusions

34. Illusions Geometrical illusions Cushion Illusion:This drawing consists solely of rectangles and squares, set straight and true; the curvature is all in your mind.

35. Illusions Luminance & Contrast

36. Illusions Luminance & Contrast The scintillating grid illusion

37. Illusions It’s a spiral right? No, these are a bunch of independent circles

38. Effect: Illusory visual motion

39. Effect: Illusory visual motion

40. Illusions Successive contrast : afterimages ... fixate the black dot in the center for 60 seconds ... … and then look at a the black dot in the right panel !   what do you see?

42. Middle Ear malleus stapes incus oval window round window external auditory canal tympanic membrane Auditory tube

44. The Inner Ear

45. The Cochlea Unwound

46. The Cochlea

47. The Organ of Corti tectorial membrane hair cells Supporting cells Sensory & motor neurons in the cochlear branch of the vestibulocochlear (VII) nerve basilar membrane

48. Transmission of sound waves Auditory ossicles Malleus Incus Stapes Cochlear nerve Scala vestibuli Oval window Helicotrema Scala tympani Cochlear duct 2 3 Basilar membrane 1 Tympanic membrane Round window (a) Route of sound waves through the ear

49. Static Balance– utricle and sacule Static vs Dynamic Equilibrium Dynamic Balance- semicircular canals

50. Semicircular Canal