chapter 6 notes Flashcards
amplitude
intensity measured in decibels and perceived as loudness
frequency
measured in number of cycles per second, or hertz, and perceived as pitch
-a physical property of a sound
timbre
characteristic sound quality of an instrument, determined by the intensities of its harmonics
transduced
conversion of one energy to an action potential that inform the brain
pinna
collect sound waves
external part of an ear
ear cannal
tube leading from the pinna to the tympanic membrane
ossicles
three small bones that transmit vibration across the middle ear, from tympanic membrane to oval window
tympanic membrane
(eardrum) taut membrane, at the inner end of the ear canal that captures sound vibrations in air
oval window
location of the cochlea at which vibrations are transmitted from ossicles to interior of the cochlea
cochlea
where transduction happens
organ of corti
is the part of the cochlea that converts sound into neural activity
main structures
1. sensory cells, or hair cells
2. framework of supporting cells
3. terminations of the auditory nerve fibers
basilar membrane
-at the base of the organ of corti
-auditory transduction
stereocilia
tiny hairs, protrude from each hair cell
-tiny
fibers that open ion channels when the stereocilia bend
-A depolarization of the hair cell occurs and
neurotransmitter is released
inner hair cells
a single row near the central axis
IHC afferents convey action potentials that provide
sound perception to the brain.
* IHC efferent lead from the brain to the IHCs, allowing
the brain to control responsiveness of IHCs.
outer hair cells
three rows
OHC afferents convey information to the brain about the
mechanical state of the basilar membrane, not sounds
themselves.
* OHC efferents lead from the brain to OHCs, allowing the
brain to modify the stiffness of the basilar membrane,
thus sharpening and amplifying sounds
inferior colliculi
the primary auditory centers of the
midbrain.
-paired grey matter structures of the dorsal midbrain that process auditory information
tonotopic organization
are arranged in a map of low to high frequency
primary auditory cortex (A1)
processes complex sounds transmitted from lower auditory pathways
-biologically relevant sound
place coding
pitch is determined by the location of the activated hair cells
temporal coding
encodes the frequency of auditory stimuli in the firing rate of auditory neurons
binaural cues
If the ears are pointed in different directions or if the head
casts a sound shadow
-intensity differences: voume
latency differences
arrival
o Onset disparity
o Ongoing phase disparity
spectral filtering
the hills and valleys of the external ear alter the amplitude of some frequencies in a sound
conduction deafness
disorders of the outer or middle ear prevent sounds from reaching the cochlea
sensorineural deafness
hair cells fail to respond to movement of the basilar membrane; no action potentials fired
central deafness
damage to auditory brain areas, such as by stroke, tumors, or traumatic brain injury
-word deafness: selective difficulty recognizing normal speech sounds
cortical deafness: difficulty recognizing all complex sounds, verbal or nonverbal
vestibular system
sensory system that detects balance. consists of several small inner-ear structures that adjoin the cochlea
-semicircular canals
-ampulla
semicircular canals
three fluid-filled tubes, connected to the utricle and saccule
o Canals (tubes) are oriented in three planes
of head movement:
Nodding (pitch, y-axis)
Shaking (yaw, z-axis)
Tilting (roll, x-axis)
ampulla
enlarged chamber at the base of
the canals; contains hair cells
papillae
bumps on tongue, contain most of the taste receptors cells
-circumvallate
-foliate
-fungiform
taste buds
embedded in the papillae, extend microvilli into
a pore where they can contact tastants
salty
sodium (Na+) ions enter taste cells via sodium channels, causing depolarization
-a second salt sensor is TRPV1 which increases sensitivity to Na+ and also detects cations of other salts in food
sour
-acids release hydrogen ions(H+) and taste sour
-sour taste cells seem to contain the same type of ion channel that allows an influx of protons, which depolarizes the cell
-the same receptor detects carbonation in drinks
sweet, bitter, and umami
specialized receptors activate second messengers within the cell
umami
meaty-savory flavor and is detected by two types of receptors
-metabotropic glutamate receptor that responds to glutamate
-receptor that is a combination of T1R1 and T1R3
gustatory system
extends from the tongue, to brainstem nuclei, to the thalamus, and ultimately to the somatosensory cortex
-how we taste
The auditory stimulus is transduced into electrical signals by the
hair cells
olfaction
sense of smell
olfactory epithelium
sense of smell start with receptor neurons in the nose- does the smelling
-supporting cells
-basal cells
-receptor neurons
olfactory bulb
provides receptors for smell
glomerulus
a complex arbor of dendrites from a group of olfactory cells; receives inputs exclusively from olfactory neurons that are expressing the same type of olfactory receptor
vomeronasal system
detects pheramones
pheramones
a chemical signal that is released outside the body of the animal and affects other members of the same species
vomeronasal organ (VNO)
-humans don’t have one
a collection of specialized receptor cells that detect pheromones and send electrical signals to the accessory olfactory bulb in the brain
