1. Hearing
Our auditory sense

2. We hear sound WAVES
The height of the wave gives us the amplitude of the sound.
The frequency of the wave gives us the pitch if the sound.

3. The Intensity of Some Common Sounds
Decibels are the measuring unit for sound energy

5. Transduction in the ear
Sound waves hit the eardrum then hammer then anvil then stirrup then oval window.
Everything is just vibrating.
Then the cochlea vibrates.
The cochlea is lined with mucus called basilar membrane.
In basilar membrane there are hair cells.
When hair cells vibrate they send impulses up the auditory nerve to the thalamus.
It is all about the vibrations!!!

6. Place Theory and Frequency Theory
Pitch Theories
Place Theory and Frequency Theory

7. Place Theory
The pitch we hear depends on the place where the cochlea’s membrane is stimulated
So some hairs vibrate when they hear high and other vibrate when they hear low pitches.

8. Frequency Theory
The pitch we hear depends on the rate of nerve impulses traveling up the auditory nerve
All the hairs vibrate but at different speeds.

9. How We Locate Sounds

10. Sensorineural Deafness
Types of Hearing Loss
Conduction Deafness
Sensorineural Deafness
Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea (such as a damaged eardrum)
You can replace the bones or get a hearing aid to help.
The hair cells in the cochlea get damaged.
Loud noises can cause this type of deafness.
NO WAY to replace the hairs.
Cochlea implant is possible.

11. Touch Receptors located in our skin.
Essential to Development – babies develop faster if stimulated by skin contact
Four skin senses – pressure, warmth, pain, cold
Simultaneously stimulating warm and cold produces a burning sensation!
Pain is a good thing! It tells us something is wrong with our body
Did You Know? Reducing or eliminating one sense can improve others! This is why when kissing, lovers minimize distraction and increase their touch sensitivity by closing their eyes!

12. Gate Control Theory of Pain
The spinal cord contains a neurological “gate” that blocks pain signals or allows them to pass through
A Naughty Question to Think About: If a person had the top of their spinal cord severed and their genitals were touched, would they still experience sexual excitement?

13. Taste (Gustation) We have bumps on our tongue called papillae.
Taste buds are located on the papillae (they are actually all over the mouth).
The more taste buds you have, the more sensitive your taste!
Sweet, salty, sour, bitter, umami
Taste enabled our ancestors to survive!

14. Smell Olfaction: sense of smell.
Fragrance molecules reach receptors at top of nose  brain’s olfactory bulb  limbic system (memory and emotion)
Smell is strongly linked to taste and emotion!
Humans can detect about 10,000 odors
Women and young adults have best sense of smell
ONLY SENSATION THAT DOES NOT GO TO THE THALAMUS FIRST
Smell

15. Kinesthetic Sense
The system for sensing the position and movement of individual body parts
Vision plays a role!
Without the kinesthetic sense you couldn’t touch the button to make copies of your buttocks.

16. Vestibular Sense Tells us where our body is oriented in space.
Our sense of balance.
Located in our semicircular canals in our ears.
Guided by cerebellum
Cirque du Soleil balancers