Sensory

1. Sensory Comparative Anatomy Tony Serino, Ph.D. Biology Department Misericordia Univ.

2. Sensation –state of awareness of external and internal conditions of the body • Four conditions for sensation: • 1. Adequate stimulus • 2. Adequate receptor (transducer) • 3. Conduction • 4. Translation (interpretation) Characteristics of Sensation • Modality –ability to interpret nerve impulses differently • Projection –referral of sensation to point of origin • Adaptation –decrease in sensitivity of receptors to continued stimulation • Afterimage –persistence of sensation after stimulus ceases

3. Referred Pain Illustrates projection.

4. Classification of Receptors • Type of Sensory Information Relayed • Exteroreceptors, Enteroreceptors, Proprioceptors • Type of Stimulus Transduced • Mechanoreceptors, Thermoreceptors, Chemoreceptors, and Nociceptors • Complexity of Receptor • Simple structure (usually single cell) –most general senses • Complex structure (many cells) –special senses

5. General Senses • Cutaneous –skin receptors • Proprioception –sense of body position • Nociception –pain perception (chemoreceptors that perceive locally secreted warning hormones (prostaglandins))

6. Distribution of Cutaneous Receptors

7. Proprioceptors

8. Muscle sensors Muscle spindles (Intrafusal fibers: -senses degree of length of muscle fibers and the rate of change in length Golgi Tendon organs –sense tension within tendon

9. Taste (Gustatory) Sense

10. Taste Bud Taste cells can also be found on skin of fish

11. Olfactory Epithelium

12. Vomeronasal Organ -may be most sensitive to pheromones

13. Neuromast Organs • Used in vibrational sense (includes sound perception) and proprioception • Consist of hair cells embedded in gelatinous matrix that holds hairs upright • Bending of hair elicits AP in the sensory neuron

14. Lateral Line of Fish • used to detect current and pulse movement in water • Hair cell stereocilia embedded in cupula • Ion channel on kinocilium opens by shearing force

15. Sound

16. Anatomy of the Ear

17. Middle and Inner Ear

18. Ossicles Amplify Sound

19. Loud Sound Protection

20. Cochlea and Cochlear Duct

21. Hair Cells in Cochlear Duct

22. Frequency Perception • Different frequency (pitch) of sound stimulates different areas of cochlear duct • The overall area stimulated relates to the sound intensity

24. Vestibular Apparatus

25. Macula of Utricle and Saccule

26. Macula

27. Hair Cell of Macula

28. AP Generation in Macula

29. Ampulla Anatomy

30. Echolocation • Acoustic area of animal must be isolated during generation of sound beam (bats use enlarged tensor tympanii m. and cetaceans use bone insulation • Project sound beam • Bats use larynx with nasal or oral projection system • Cetaceans use nasal sound production with a specialized organ to focus sound (mellon) and the shape of their skull

31. Vision

32. Accessory Structures of the Eye

33. Lacrimal Apparatus

34. Extrinsic Ocular Muscles

35. Action and Innervation of Ocular Muscles

36. Eye Anatomy

37. Aqueous Humor Flow (Canal of Schlemm) Glaucoma results frominadequate drainage ofAqueous Humor leading to increase pressure in the eye.

38. Iris controls amount of light entering the eye.

39. Distant Vision

40. Near Vision (Accomodation)

41. Near and Far-sightedness

42. Astigmatism and Presbyopia • Astigmatism –results from imperfections in the resolving structures in the eye (lens and/or cornea) • Presbyopia is the loss of near vision with age; resulting from a decrease in elasticity of the lens.

43. Increase lens opacity with age. Cataract

44. Retina Cellular Arrangement

45. Special Areas of Retina

46. Blind Spot Optic Disc(blind spot) Optic N.

47. Photoreceptors: Cones and Rods

48. Three Population of Cones

49. Visual Processing

50. Infra-red Sense • T-mem sensitive to 0.003oC temp. change • air chamber prevents heat from being quickly dissipated to body tissues Outer chamber Air filled inner chamber Insulating tissue Thermosensory membrane (T-mem)