1. Special senses (continued)

2. Receptors are classified into 3 types Exteroceptors – located near the body surface, are specialized to perceive stimuli from the external environment; other exteroceptors include receptors for vision, hearing, smell and taste Interoceptors – are specialized to perceive sensory information from visceral organs Proprioceptors – located in joint capsules, tendons, muscle spindles, inner ear, are specialized to perceive information that relates to an awareness of the body in space and movement

3. Anatomy of the vestibulo-cochlear organ

4. Vestibulo-cochlear organ includes Outer ear – Auricula – External acoustic meatus – Tympanic membrane Middle ear – Tympanic cavity – Three ossicles: malleus, incus, stapes – Auditory (Eustachian) tube Inner ear – Bony and membranous labyrinths

5. External acoustic meatus

6. Middle ear

7. Bony, membranous and sensory labyrinths

8. Inner ear Bony labyrinth – Cochlea – Vestibulum – Three semicircular canals Membranous labyrinth – Cochlear duct – Sacculus and Utriculus – Three semicircular ducts Sensory labyrinth

9. Macula of the utricle: hair cells

10. Hair cells of the maculae

11. Crista ampullaris of the semicircular duct

12. LM of the crista ampullaris and of macula

13. SEM of the hair cells and the otoliths

14. Organ of Corti in the cochlear duct

15. Axial section through the cochlea

16. LM of the organ of Corti

17. SEM of the organ of Corti hair cells

18. Histophysiology of the organ of Corti

19. Olfactory perception (odors detection)

20. The olfactory region

21. LM of the human olfactory mucosa

22. EM of the rat olfactory epithelium

23. Taste perception (taste buds)

24. Lingual papillae and a taste bud

25. LM of taste buds in circumvallatae papilla

26. EM of a taste bud

27. Mechanoreceptors include Nonencapsulated – peritrichial and corneal naked nerve endings – Merkel’s disks Encapsulated – Meissner’s corpuscles – Pacinian corpuscles – Ruffini’s corpuscles – Krause’s end bulbs – Golgi tendon organs – Muscle spindles

28. Various types of mechanoreceptors A, Merkel’s disk; B, Meissner’s corpuscle; C, Pacinian corpuscle; D, Peritrichial nerve endings; E, Ruffini’s corpuscle; F, Krause’s end bulb; G, Muscle spindle; H, Golgi tendon organ

29. Free nerve endings

30. Merkel’s cells and Merkel’s disks

31. Meissner’s and Pacinian corpuscles

32. Muscle spindle