Title: Sensation- Day 2
1Sensation- Day 2
- Review Questions
- Define sensation and perception, and discriminate
between the two. - What is the retina, and what happens there?
- Describe the basic idea behind the Trichromatic
Theory of color vision? - Distinguish between bottom-up processing and
top-down processing, and give an example of each.
2Hearing
3Why do we have two ears?
4Sound
- Sound, like light, comes in waves
- Sound is vibration
- Features of sound include
- Pitch
- Hertz
- Decibels
5Pitch
- A sounds highness or lowness
- Dependent on the frequency of the sound wave
- Is measured as hertz (Hz)
6Hertz (Hz)
- A measure of the number of sound wave peaks per
second measures frequency - Determines the pitch of the sound
- Human hearing goes from 20 Hz to 20,000 Hz
7Decibel (dB)
- A measure of the height of the sound wave
- Determines the loudness of the sound
- Sometimes called amplitude
8Amplitude is how loud the sound is. The higher
the crest of the wave is the louder the sound is.
It is measured in decibels.
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10Hearing The Structure of the Auditory System
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12Auditory Canal
- The opening through which sound waves travel as
they move into the ear for processing - Ends at the tympanic membrane (eardrum)
13Parts of the Ear Auditory Canal
14Tympanic Membrane (eardrum)
- The tissue barrier that transfers sound vibration
from the air to the tiny bones of the middle ear - Can be damaged by objects in the ear or
exceptionally loud noises
15Parts of the Ear Tympanic Membrane
16Ossicles
- Three tiny bones that transfer sound waves from
the eardrum to the cochlea - Hammer, anvil and stirrup
17Parts of the Ear - Occicles
18Cochlea
- A hearing organ where sound waves are changed
into neural impulses - The major organ of hearing
- Filled with fluid a snail shaped body tube
Cochlear Implant
19Parts of the Ear - Cochlea
20Hair Cells
- The receptor cells for hearing in the cochlea
that change sound vibrations into neural impulses - Similar to the rods and cones within the eye
21Parts of the Ear - Hair Cells
22Auditory Nerve
- The nerve that carries sound information from the
ears to the temporal lobes of the brain
23Parts of the Ear Auditory Nerve
24Semicircular Canals
- Organs in the inner ear used in sensing body
orientation and balance (vestibular sense) - Relies on fluid in the canals
- Spinning in circles disrupts the fluid.
25Parts of the Ear Semicircular Canals
26Divisions of the Ear
- Ears structure can be divided into
- The outer ear
- The middle ear
- The inner ear
27Divisions of the Ear
28Divisions of the Ear
29Divisions of the Ear
30How do we perceive differences in pitch?
31Place Theory
- We hear different pitches because different sound
waves trigger activity at different places along
the cochleas basilar membrane.
32Frequency Theory
- We sense pitch by the basilar membrane vibrating
at the same rate as the sound. - But this theory has trouble explaining high pitch
sounds because our hairs cannot vibrate at
certain speeds.
33Hearing loss
- Conduction Hearing Loss caused by damage to
mechanical system of ear.
- Sensorinueral hearing loss caused by damage to
cochleas receptor cells or to auditory nerves.
Cochlea Implant
34Smell and Taste
35Why do we study smell and taste together?
- SENSORY INTERACTION the principle that one sense
may influence another.
36Taste
- Taste is a chemical sense.
- Receptor cells are located primarily on the
tongue and in the mouth. - Four different tastes
- Salty, sweet, sour and bitter
- Damaged taste receptor cells are replaced within
a few days.
37Tongue
38Taste Buds
Map out the tongue
39Papillae
- Those bumps on our tongue are called Papillae.
- Papillae help grip food while your teeth are
chewing. - They also have another special job - they contain
your taste buds
40TASTE
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41PTC Strips
42But what about smell?
- Can our sense of smell be biologically based?
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44Smell
- Smell is a chemical sense.
- Olfactory cells in the upper nasal passages
detect molecules in the air. - Taste and smell interact to produce flavor.
45Olfactory Cells
- The chemical receptor cells for smell
- Located in the nasal passages
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48So can we smell the difference?
Pheromones
- Chemical messengers that are picked up through
our sense of smell between males and females - Founded in the early 1930s by studying
silkworms. - Jury is still out on whether they exist in
humans.
49Body Senses
50Kinesthetic Sense
- Tells us where our body parts are.
- Receptors located in our muscles and joints.
Without the kinesthetic sense you could not touch
the button to make copies of your buttocks.
51Kinesthetic Sense
- The system for sensing the position and movement
of individual body parts - Relies on receptor cells from the muscles and
joints - Ones leg falling asleep is a disruption of the
kinesthetic sense
52Vestibular Sense
- Tells us where our body is oriented in space.
- Our sense of balance.
- Located in our semicircular canals in our ears.
53Parallel Processing
- The processing of several aspects of a problem
simultaneously.
Motion
Form
Color
Depth
54Feature Detection
- The concept that specific nerve cells in the
brain respond to specific features of the
stimulus, such as shape, angle, or movement.
55The End