(flip it) module 20
➢ Our ​audition​ is highly adaptive
○ Audition is another word for hear
➢ Sounds with frequencies in a range of the human voice are
sounds we hear best
➢ Those with normal hearing are acutely sensitive to faint sounds
SOUND WAVES ARE BANDS OF COMPRESSED AND EXPANDED AIR
OUR EARS DETECT CHANGES IN AIR PRESSURE AND TRANSFORM THEM INTO
NEURAL IMPULSES
Stimulus input: sound waves
➢ Ex 1) A bow across a violin releases energy of ​sound waves
➢ Jostling molecules, each bumping into the next, c​reate waves of
compressed and expanded air
➢ Ex 2) swimming in ​ocean of moving molecules
➢ We can ​feel the vibration​ as our ears ​detect brief air pressure
changes
➢ We hear by both air and bone conduction
➢ Amplitude​ of waves determine their ​loudness​ (al)
➢ Their length, or ​frequency​ determine the ​pitch​ we experience
(fp)
○ Frequency​ is the number of wavelengths that pass a point
in a given time
○ Pitch​ is a tone’s experienced highness or lowness
➢ We measure sound in decibels
The Ear
➢ When sound waves enter the ​outer ear​..
○ Process that ​transforms vibrating air into nerve impulses​,
which our brain decodes as sounds, begins
○ Our brain decodes as sounds
1. Stimulus
2. Vibrating air
3. Outer ear (auditory canal):
a.
channels the waves through the ​auditory canal​ to the
eardrum​ ( a tight membrane) causing it to vibrate
4. Middle ear:​ ( includes hammer, anvil, and stirrup)
a. Chamber between the eardrum and cochlea
b. Concentrate vibrations of eardrum
c. pick up vibrations and sends it to the ​cochlea
5. Inner ear​:
a. cochlea​: a snail shaped tube in the inner ear that is a
fluid-filled tube
i.
that triggers nerve impulses
b. Vibrations cause the ​cochela’s membrane​ (oval window) to
vibrate which ​jostles the fluid
c. Rippling of the basilar membrane ​caused by pressure
changes in the fluid, ​triggers movement of tiny hair cells
i.
Basilar membrane is where the hair like cells detect
vibrations
d. Axons of those cells converge to create auditory nerve,
which sends neural impulses
e. Trigger ​messages​ to be ​sent to auditory cortex (via
thalamus) ​in brain
➢ Cochlear implant: device that converts sounds into electrical
signals
○ Stimulates auditory nerve through electrodes (in the
cochlea)
○ Less common form of hearing loss
➢ Sensorineural​ ​hearing (nerve deafness): hearing loss caused by
damage to cochlea's hair cell receptors
○ Disease can sometimes cause hearing loss
○
Most likely biological changes linked with hereditary,
aging, and exposure to ear-splitting music are the
culprits
➢ Conduction hearing loss: hearing loss caused by damage to
mechanical system
○ The mechanical system conducts sound waves to the cochlea
Perceiving pitch
➢ Place theory: explains how we hear high pitched sounds (ph)
○ Links pitch we hear with place where cochlea’s membrane is
stimulated
■ High pitch sounds are steep
○ Proposes that we hear different pitches because sound
waves trigger activity at different places along the
cochlea’s basilar membrane
➢ Frequency theory: explains how we hear low pitched sounds (fl)
○ Proposes that our brain reads pitch by monitoring
frequency of neural impulses traveling up the auditory
nerve
○ The whole basilar membrane vibrates at the frequency of
the sound
➢ Volley theory: how we hear pitches in middle range
○ Neurons alternate firing to process the highest pitch
sounds
○ Connect the volley principle to biopsychology
module 21:
➢ Types of touch (cowpp)
○ Pressure
○ Warmth
○ Cold
○ pain
➢ Understanding pain
○ Biological influences
■ Spinal cord​ contains a gate that blocks pain signals
or allows them to pass to the brain
■ Gate ​opened ​by activity of pain signals
■ TRAVELING UP TO THE BRAIN by ​small nerve fibers
■ Closed​ by activity in ​larger nerve fibers​ or
INFORMATION TRAVELING DOWN FROM THE BRAIN
■
○
➢
➢ Biopsychosocial Approach
○ Psychological Influences
■ Attention to pain
■ Learning based on experience
■ Expectations
○ Biological Influences
■ Activity in spinal cords large and small fibers
■
○
➢ Taste
○ Basic tongue receptors for sweet, sour, salty, bitter, and
umami
➢ Smell (aka olfaction)
○ Source: Inhale and exhale nearly 20,00 breaths of air
○ Receptor: Millions of receptors at top of nasal cavity
○ Dogs have more olfactory senses
○ Olfaction
■ Chemical sense
■ Odor molecules
■ Olfactory bulb
■ Olfactory nerve
➢ Body Position and Movement
○ Kinesthesia
■ System for sensing the position and movement of
individual body parts
○ Vestibular sense
■ The sense of body movement and position, including
sense of balance
■ Movement of fluids in inner ear caused by head/body
movement
■ Receptors: Semicircular canals (in Inner ear) helps
maintain your balance
➢