AUDITION and its components and sensory organs.pptx

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1. Audition, the Body Senses, and the Chemical Senses - Week 8

2. OUTLINE Audition - Vestibular system - Somato -senses - Gustation - Olfaction

3. Hearing and the Other Senses What role does ear play in the senses of sound, motion, & balance? How do smell & taste function? What are the skin senses, & how do they relate to the experience of pain?

4. Sensing Sound Sound: M ovement of air molecules brought about by a source of vibration

5. Outer ear: pinna, auditory canal, ear drum Ear Drum: part of ear that vibrates when sound waves hit it Collect & bring sounds into the internal portions Sound localization Middle Ear : tiny chamber, three bones here (hammer, anvil, stirrup) Transmit vibrations to oval window oval window : thin membrane leading to inner ear

6. Inner ear : cochlea, basilar membrane, hair cellschanges sound vibrations into a form in which they can be transmitted to the brain Cochlea: coiled tube in the ear filled with fluid that vibrates in response to sound Basilar membrane : inside cochlea, vibrating structure that runs through the center of cochlea, dividing it into an upper chamber & containing sense receptors for sound Hair cells : basilar membrane is covered with hair cells specialized to send neural message to brain

7. Physical aspect of sound Sound waves require a medium (air, water etc ) to travel Frequency: no. of wave cycles that occur in a sec Low frequency & high frequency Low f are translated into a sound of low in pitch Pitch makes sound seem “high” or “low” Low f that humans are capable of hearing is 20 hz Higher f are sound of higher pitch People can detect 20,000 hz

8. Amplitude : allow us to distinguish b/w loud & soft sounds Spread b/w up-&-down peaks Waves with small peaks: soft sound & vice versa We are capable of hearing 120 db. sound Sensitivity to different f changes with age

9. Theories of Sound How brains able to sort wavelengths of different f & intensities? Place theory of hearing Frequency theory of hearing

10. Place theory of hearing: Different areas of basilar membrane respond to different f Part of basilar membrane near to oval window is most sensitive to high f Part of basilar membrane nearest to cochlea’s inner end is most sensitive to low f

11. Frequency theory of hearing: Entire basilar membrane acts like a microphone, vibrating as a whole in response to a sound High pitch, high f impulse transmit to brain A theory of pitch perception first proposed in 1886 by the British physiologist  William Rutherford  (1839–99) according to which the ear converts acoustic vibrations into nerve impulses by emitting one impulse for each cycle of the sound wave in the manner of a telephone.

12. Balance: The Ups & Downs of Life Vestibular system: The functions of the vestibular system include balance, maintaining the head in an upright position, and adjusting eye movement to compensate for head movements Respond to pull of gravity & allows us to maintain our balance, even when standing semicircular canals of inner ear consists of 3 tubes, containing fluid that sloshes through them when head moves, signaling rotational movement to brain

13. Smell & Taste Smell Many animals have keener ability to detect odors than we do More than 1000 receptor cells, known as olfactory cells, spread across the nasal cavity, specialized to react to particular odors Olfaction (sense of smell) permits us to detect more than 10,000 separate smells Sniff tests: women have better sense of smell than men do

14. Molecules of substance travel through the nasal cavity olfactory cells (receptors neurons of nose, spread across nasal cavity) Smell also acts as hidden mean of communication Non human release pheromones – chemicals they secret into environment that produce a reaction in other members of same species

15. Taste There are 10,000 taste buds on the tongue & other parts of mouth Taste buds wear out & are replaced every 10 days/2 weeks If our taste buds were not reproducing, we would lose ability to taste after we’d accidently burned our tongues.

16. Sense of taste (gustation) involves receptor cells respond to 4 basic stimulus qualities sweet, sour, salty, bitter 5 th category a flavor called umami (savory) Every taste is simply a combination of basic flavor

17. Sense of taste differs from one person to another – genetic factor Super tasters – highly sensitive to taste, have twice as many taste receptors, more female than males find sweet sweeter, cream creamer etc , Non tasters – relatively insensitive to taste, Seek out relatively sweeter foods in order to maximize taste

18. The Skin Senses: Touch, Pressure, Temperature, & Pain Skin senses: senses of touch, pressure , temperature & pain play a critical role in survival, making us aware of potential danger If you never experienced pain, you might not notice that your arm had brushed against a hot pan, & you would suffer a severe burn Without warning sign of abdominal pain, typically accompanies an inflamed appendix, that might eventually rupture, spreading a fatal infection throughout body

19. Most of these senses work through various receptor cells located at various depths through out skin, distributed unevenly throughout the body E.g ; fingertips – more receptor cells sensitive to touch Pain: most extensive – Pain is outcome of cell injury When cell damage, releases chemical called “substance p” that transmits pain message to brain people consult physicians & take medication for pain It is a response to great variety of stimulus E.g ; too bright light , too loud sound– pain

20. Some people are more susceptible to pain than others e.g ; women These gender differences are due to hormones and genetic Pain is a perceptual response that depends heavily on emotions & thoughts Gate control theory of pain: Particular nerve receptors in spinal cord lead to specific areas of brain related to pain When these receptors are activated due to injury, a “gate” to brain open, allowing us to experience sensation of pain

21. Gate can be shut in 2 different ways 1 st : rubbing the skin around an injury 2 nd : psychological factors (emotions, interpretation of events) Cultural differences in experience of pain Body’s own pain killer “ endorphins”. The Gate Control Theory of Pain (va.gov)

22. Strategies to fight pain Medication (painkilling drugs) Nerve & Brain stimulation (low voltage electric shock) Light therapy (exposure to certain wavelength) Hypnosis Biofeedback & relaxation technique (learn to control “involuntary” functions) Surgery Cognitive Restructuring

23. How Our Senses Interact Synesthesia : exposure to one sensation (sound) evokes the other (vision ) Synesthesia: Definition, Examples, Causes, Symptoms, and Treatment (healthline.com) Multimodal perception : B rain collect info from individual sensory system & integrates & coordinates it For the last few decades, perceptual research has pointed to the importance of  multimodal perception : the effects on the perception of events and objects in the world that are observed when there is information from more than one sensory modality. Most of this research indicates that, at some point in perceptual processing, information from the various sensory modalities is  integrated . In other words, the information is combined and treated as a unitary representation of the world.