Unit 4 - Hearing and Other Senses

May be hard to see in dark mode

The Process of Hearing

Sound Wave to Receptor Cells

A sound wave goes into the auditory canal from the pinnae and reverberates on the eardrum (tympanic membrane) which initiates the three small bones in the middle ear: the hammer (malleous), next the anvil (incus), and then the stirrup (stapes). The stirrup attaches to the cochlea through the oval window. The vibration sent through the oval window then stimulates the receptor hair cells on the basilar membrane of the cochlea.

Neural Impulse to Brain

The hair cells lining the basilar membrane ripple from the vibrations sent through the oval window. This triggers a neural message to be sent through the auditory nerve. The auditory nerve then sends this message to the thalamus in the cerebral cortex. Next, the thalamus transmits the message to the auditory cortex in the temporal lobe for the brain to interpret. Depending on the speed of the message travelling through the auditory nerve (frequency theory), and where the basilar membrane was stimulated (place theory), the brain will read the pitch as high (frequency) or low (place).

Sound Waves

Amplitude determines a sound’s loudness
Frequency determines the pitch
Loudness is measured in decibels (d)
- Every 10d increase = 10x louder sound

Stereophonic hearing allows us to determine the %%direction and distance%% of a sound.

Hearing Loss and Deaf Culture

Conduction hearing loss is caused by $damage to the eardrum or three bones of the middle ear.$
- Treatment - Hearing aids
Sensorineural hearing loss (nerve deafness) is caused by ==damage to the cochlea’s receptor hair cells or to the auditory nerve.==
- Treatment - Cochlea implants

Other Senses

Touch

Pain

Many things influence pain:
socio-cultural influences
“suck it up”
psychological influences
memories of pain
rubber-hand illusion
placebo

Biopsychosocial Approach = biological influences + psychological influences + social influences = personal experience of pain

Gate control theory - spinal cord contains neurological “gate” that blocks or allows pain signals to pass onto the brain

how to block the "gate" 
1. massage
2. medication/accupunture
3. release of endorphins
4. distraction
5. placebo
6. empathy of cargiver

Smell

smell is the only sense that doesn't go through the thalamus first

Sensory adaptation in smell is faster than other senses.

Taste (Gustation)

the acutal anatomy of the tongue is not important, just know that it looks like this

The different types of taste are based on survival instincts from our ancestors who’ve evolved to associate certain tastes with certain dangers.

Taste	Indicates
sweet	energy source
salty	sodium essential for physiological processes
sour	potentially toxic acid
bitter	potential poisonous
umami	proteins to grow and repair tissue

{{CHILDREN = MORE SENSITIVE TO TASTE{{

McGurk Effect - shows interaction between sense…smell and taste*