Ch. 5: Sense Perception pt. II Flashcards
Top two most important senses for humans in order
vision then hearing
Process for hearing
sound wave hits ear drum, enters the middle ear (begins after the eardrum), then transfers to the ossicles. The ossicles then transfer the vibrations to the oval window. The oval window’s vibrations prompt the basilar membrane to oscillate, which stimulates hair cells. Hair cells are the primary auditory receptors, and so convert these waves into neural signals that travel to the brain.
The ossicles
The hammer, anvil, and stirrup.
The cochlea
Located in the inner ear. A fluid filled tube that is curled like a snail shell with a membrane at the end called the round window, and a membrane at the start called the oval window. Running through the center of the cochlea is the basilar membrane.
Vestibular sense
Uses information from the receptors in the semi-circular canals of the inner ear to help us keep our balance.
Cochlear implant
Can provide the sense of sound to someone who has a severe hearing impairment.
Two mechanisms for encoding the frequency of an auditory stimulus
Temporal coding and place coding
Temporal coding
Used to encode relatively low frequencies, such as the sound of a tuba. The firing rates of cochlear hair cells match the frequency of the pressure wave, so that a 1,000 Hz tone causes hair cells to fire 1,000 times per second. This can occur up until about 4000Hz, after which temporal coding can only be maintained if the hair cells fire in volleys.
Place coding
Different sound frequencies activate receptors at different locations along the basilar membrane. Hair cells at the base of the cochlea are activated by high-frequency sounds, meanwhile hair cells at the end of the cochlea are activated by low-frequency sounds. In this manner, the frequency of a sound wave is encoded by the receptors along the basilar membrane that vibrate the most.
Taste receptors
Located on taste buds, mostly on the tongue but are also spread throughout the throat.
The 5 tastes
sweet, sour, bitter, spicy, umami
olfaction
sense of smell. has direct route through the brain, specifically to the prefrontal cortex and amygdala.
olfactory epithelium
A thin layer of tissues embedded with thousands of smell receptors. Each receptor is sensitive to different odorants. Humans can discriminate between 1 trillion odorants.
olfactory bulb
Located just below the frontal lobes, it is the brain center of smell and signals go directly to it, bypassing the thalamus.
Haptic sense + specifics of how you sense it
Sense of touch. Haptic receptors for both temperature and touch are located in the skin’s outer layer, and their long axons reach the spinal or cranial nerves to enter into the CNS. There are separate receptors to detect warm and cold. There are one type of pressure receptor at the base of hair follicles that detect movement of the hair, and there are 4 other type of pressure receptors in the skin that respond to vibrations, light fast pressure, light slow pressure, and stretching.
