1. Warm up 03/06/2012
The oily secretions that lubricate the eye are produced by the:
A) ceruminous glands
B) lacrimal glands
C) meibomian glands
D) apocrine glands
E) ciliary glands
The blind spot is located at the:
A) fovea centralis
B) ciliary body
C) optic disk
D) pupil
E) choroid

2. Virtual Eye Dissection

3. Sensory System
Ear: Sound & Balance

4. 3 Parts: Outer – Middle - Inner

5. Outer Ear: Auricle
Called the Pinna
Fx: Collects sound waves

6. Outer Ear: External Auditory Canal
Extends from Pinna to eardrum
Fx: Transmits sound waves

7. Outer Ear: External Auditory Canal
Produces Cerumen (wax)
Fx: Traps foreign bodies

8. Middle Ear: Air-filled Converts sound waves to mechanical energy
Amplifies it
Conducts to next chamber

9. Components: Tympanic membrane – Eardrum Vibrates Sound to Mechanical
Energy

10. Perforated Eardrum:

11. Inflammation of the middle ear
Otitis Media
Inflammation of the middle ear

12. Components: Ossicles – 3 bones Fx: Mechanical vibration
Malleus (Hammer)
Incus (Anvil)
Stapes (Stirrup)
Fx: Mechanical vibration

13. Middle Ear: Ossicles

14. Ear Ossicles

15. Middle Ear:
Oval window - Tranfers mechanical vibration from middle ear to inner ear

16. View of OVAL WINDOW
Oval Window

17. Middle Ear opens to Nasopharynx via Eustachian tube

18. Adjusts pressures between middle ear & outside Drains middle ear
Eustachian Tube
Fx:
Adjusts pressures between middle ear & outside
Drains middle ear
Picture – as it opens to nasopharynx

19. Swallowing & yawning open it
Eustachian Canal
Normally closed
Swallowing & yawning open it
Tympanic membrane will not vibrate well if pressures not equal
Fluid in canal behind ear drum

20. If fail to open, increased pressure (pain) and infections
Eustachian Canal
If fail to open, increased pressure (pain) and infections
Fluid in canal behind ear drum

21. Requires Ear Tubes – drain the excess fluid & prevent infection

22. Labyrinth
Inner Ear

23. Bony Chambers (fluid-filled)
Inner Ear
Bony Chambers (fluid-filled)
Vestibule
Semicircular Canals
Cochlea

24. Inner Ear Bony Labyrinth

25. Inner Ear Bony Labyrinth
Fluid-filled = Perilymph
Membranous sac is suspended in the periliymph = Membranous labyrinth

26. Inner Ear Bony Labyrinth
Sac contains thick fluid = Endolymph

27. Hearing and the Inner Ear - Cochlea
Snail-like shape
Membranous sac contains organ or Corti

28. Cochlear Ducts
Membranous labyrinth
Perilymph
Endolymph
Organ of Corti

29. Cochlear Ducts

30. Organ of Corti Contains specialized hearing receptors or hair cells
Embedded in basilar membrane

31. Organ of Corti Hair cells covered by gel membrane (Tectorial membrane)
Corti converts mechanical energy into electrochemical energy

32. Hearing Process Ossicles vibrate oval window
Sets the fluids into motion (pressure waves)

33. Cochlear Ducts

34. Hearing Process Vibrate basilar membrane
Hair cells rub tectorial membrane (bent)

36. Hearing Process Hair cells transmit impulse to cochlear nerve
Interpretation of sound in temporal lobe

37. Hearing Process Hair cells transmit impulse to cochlear nerve
Interpretation of sound in temporal lobe

38. Sound Energy to Hearing Interpretation
Mechanical
Energy
Mechanical 
Electrochemical

39. Ear Notes Part 1 Review

40. How old is your ear?

41. Balance: Static Equilibrium
Position of head when not moving (which way is up)
Membranous sacs in vestibule contain maculae

42. Maculae Physiology As head moves, otoliths roll in response to gravity
Pulls on gel and bends hairs in receptors

43. Maculae Physiology Hair cells send impulse via vestibular nerve
Signal to cerebellum for interpretation

44. Balance: Dynamic Equilibrium
Rotation of head or movement is detected
Membranous semicircular canals filled with endolymph

45. Crista Ampullaris
Membranous semicircular canals contain crista ampullaris

46. Crista Ampullaris
Contains receptor cells (w/ hairs) embedded in cupula (gel-like cap)

47. Ampullaris Physiology
When head moves, endolymph lags behind
Cupula drags against endolymph current and bends hairs

48. Ampullaris Physiology
Stimulates hair cells to send impulse
Vestibular nerve sends impulse to cerebellum

49. Bill Nye Sound