Part 3. Auditory Sense. Auditory Organ -- Ear

Size: px

Start display at page:

Download "Part 3. Auditory Sense. Auditory Organ -- Ear"

Chloe Patterson
7 years ago
Views:

1 Part 3. Auditory Sense Auditory Organ -- Ear

2 Ear hears sound Sound is a mechanical disturbance propagated through an elastic medium

4 Hearing Threshold Hearing Threshold Pressure threshold Frequency Range of hearing of the human ear 20~20000Hz

5 Structure of the Ear External ear Middle ear Inner ear

11 Auditory Function of Ear Conduction system of sound Pinna, External auditory canal, Tympanic membrane, Ossicular chain (Malleus, Incus, Stapes), oval window, scala vestibuli, Vestibular membrane, Cochlear duct, basilar membrane, scala tympani, round window. Receptor system Organ of Corti

12 Conduction system -- External Ear Pinna: helping to pinpoint the location of sounds External auditory canal: A resonator

13 Conduction system -- Middle ear Potent conduction of sound from the tympanic membrane to the cochlea Tympanic membrane Ossicular chain malleus, incus and stapes Eustachian tube

14 Cochlea Vestibular apparatus Inner Ear

15 Conduction system -- Inner ear Pathway of conduction of vibration in the inner ear Two Membranes Vestibular membrane Basilar membrane Organ of Corti Three tubes Scala vestibuli Cochlear duct Scala tympani

16 Two types of sound conduction Air conduction Bone conduction

17 Receptor system -- Organ of Corti

18 Electrical phenomena in the cochlea Hair cells Resting membrane potential -70 mv Endocochlear potential (Endolymphatic potential): +80mV Microphonic potential Action potential

19 Mechanism of hair cell excitation Excitation of the hair cell

21 The sense of the different frequency sound Traveling wave theory

22 Travel of the Vibration Waves Pattern of vibration of the basilar membrane for different sound frequencies Low-frequency sound Medium-frequency sound High-frequency sound

23 Hearing Abnormalities Types of deafness Nerve deafness Impairment of the auditory nerve Impairment of the cochlea Conduction deafness

24 Category of Hearing Loss Mild Hearing Loss (26 ~ 40 db) Moderate Hearing Loss (41~ 55 db) Moderately Severe Hearing Loss (56 ~ 70 db) Severe Hearing Loss (71~ 90 db) Profound Hearing Loss (Over 90 db)

25 Treatment of deafness Audiphone Artificial cochlea

26 Auditory Organs

27 Part 4. Vestibular Apparatus

28 Structure of vestibular apparatus Utricle, saccule, semicircular canals

29 Functions of the Vestibular apparatus The vestibular system detects changes in the motion and position of the head by the use of fluid-filled tubes. To provide a subjective sensation of movement and position in 3-dimensional space and spatial memory To maintain upright body posture by reflex mechanism To remain the eyes fixed on the same point in spite of changes in head position

30 Receptor Cells in Semicircular duct

31 Sensory mechanism of hair cells in Ampulla

32 Detection of angular acceleration / deceleration of head

33 Detection of head rotation (angular acceleration / deceleration )

34 Receptor cells in Utricle and Saccule Cyst Macula Hair cells

35 Sensory mechanism of hair cells

36 Detection of linear acceleration / deceleration of head Utricle detects motion in the horizontal direction Saccule detects motion in the vertical direction

37 Vestibular Response Nystagmus A rapid, involuntary, oscillatory motion of the eyeball Reflex of body pose Response of automatic nerve system

38 Part 5. Sense of Smell and Sense of Taste

39 Six Primary Odor Qualities Floral Ethereal Musky Camphor Putrid Pungent

40 Structure of smell organ Upper nasal cavity

41 Receptor cells of Smell Smell receptor: Olfactory cell

42 Pathway of smell Transmission of smell signals into the central nervous system

43 2004 Nobel Medicine/Physiology Prizer "for their discoveries of odorant receptors and the organization of the olfactory system." Richard Axel Linda Buck

44 Elementary taste qualities Salty Sweet Sour Bitter Umami

45 Structure of Taste organ Tongue

46 Receptor cell of Taste Taste bud

47 Pathway of taste Transmission of taste signals into the central nervous system

48 General Questions How does the vibration of the basilar membrane encode different frequencies of the sound? Describe the function of the vestibular apparatus.

A diagram of the ear s structure. The outer ear includes the portion of the ear that we see the pinna/auricle and the ear canal.

A diagram of the ear s structure THE OUTER EAR The outer ear includes the portion of the ear that we see the pinna/auricle and the ear canal. The pinna or auricle is a concave cartilaginous structure,