Lecture 15: From Vision to Hearing Flashcards
1
Q
Characteristics of hearing
A
- Hard to obstruct
- Can hear from 360 degrees
- Communication and language
- Courtship
- Defense
- Music
2
Q
Sound
A
- Vibrations that travel through air or another medium
- Speed of sound in air at STP ~340m/s
3
Q
Sound Frequency
A
Determines our sense of pitch in Hz
4
Q
Pure Tone
A
Sound with a sinusoidal waveform
4
Q
Sound Amplitude
A
Determines our sense of loudness in dB
4
Q
Spectrogram
A
Shows the frequencies the make up the sound and how they change overtime
4
Q
Fourier Transform
A
Decomposition of a sound to the frequencies that make it up
5
Q
Complex Sounds
A
- Most sounds are not pure tones
6
Q
The Ear Pathway
A
- The pinna collects sound and directs it down the ear canal
- Sound air pressure waves strike the tympanic membrane
- Middle ear bones pass vibrations to the cochlea
6
Q
Pitch Perception in Different Species
A
- Humans: 20Hz-20,000Hz
- Elephants: 10Hz-12,000Hz
- Cats extend higher
- Bats far higher: 20,000-200,000Hz
6
Q
Cochlea and Basilar Membrane
A
- Coiled tube containing the basilar membrane, which vibrates with the sound waves
- Basal end of the BM vibrates with high frequency sounds, and apical end with low pitched sounds. It is organized tonotopically
7
Q
Hair Cells
A
- Vibrations of the basilar membrane causes movement of hair cells called stereo cilia
- Movement of hair cells open K+ channels, depolarizing the cell
- Depolarization causes neurotransmitter (glutamate) release (no action potentials) to the cochlear nucleus in the brainstem
8
Q
Superior Olivary Nucleus
A
- The cochlear nuclei send information to the superior olivary nuclei
- Brainstem nuclei critical for sound localization
- Medial Superior Olive detects intramural time differences
- Lateral Superior Olive detects interaural level differences
9
Q
Noise and Age Related hearing Loss
A
- One in three people in the US between 65-74 have hearing loss
- Enhanced by excessive exposure to loud sounds
- Often due to death of hair cells
9
Q
Hearing Aid
A
- A small electric device that amplifies sounds
- 3 basic parts: microphone, amplifier, and speaker
