Chapter 46: Sensory Systems Flashcards
first step of sensory transduction
change in the membrane potential of the receptor cell in response to specific type of stimulus
receptor potential
change in the membrane potential of a receptor cell
ionotropic sensory receptors
mechanoreceptors, thermoreceptor, electroreceptors
metabotropic sensory receptors
chemoreceptor, photoreceptor
adaptation
enables an animal to ignore background or unchanging conditions while remaining sensitive to changes and new information
chemoreceptors
receptor proteins that bind to specific molecules and are responsible of smell and taste
olfaction
the sense of smell, dependent on chemoreceptors
olfactory bulb
olfactory integration area of the brain
odorant
molecule in the environment that binds to and activates an olfactory receptor protein on the cilia of olfactory receptor neurons
pheromone
specialized chemical signal used for communication among individuals of the same species
gustation
sense of taste, dependent on taste buds (chemoreceptors)
mechanoreceptors
respond to mechanical forces
merkel’s discs
adapt rather slowly and provide continuous information about anything touching the skin. most important tactile receptors
meissner’s corpuscles
very sensitive, adapt rapidly, provide information about changes in things touching the skin
ruffini endings
deeper in the skin, adapt slowly and are good at providing information about vibrating stimuli of low frequency
pacinian corpuscles
adapt rapidly, provide information about vibrating stimuli of higher frequencies
muscle spindles
stretch receptors. modified muscle cells embedded in connective tissue inside muscles and innervated by sensory neurons
golgi tendon organ
type of mechanoreceptor.
found in tendons and ligaments
provides information about the force generated by a contracting muscle
hair cells
mechanoreceptor for the vertebrate auditory system and vestibular system. ( Sound perceiving and equilibrium-maintaining systems)
stereocilia
fingerlike projections of the cell membrane stiffened by cross-linked actin filaments
tympanic membrane
covering the end of the auditory canal
vibrates in response to pressure waves traveling down the canal, converting the pressure waves to physical forces in the middle ear
eustachian tube
filled with air, pressure equilibrates between the middle ear and the enviornment
ossicles
composed of the malleus, incus, and stapes
transmits the vibrations of the tympanic membrane to oval window
oval window
receives vibrations from stapes. pressure is now 20x greater than at tympanic membrane
vestibular canal
part of the inner ear. organ of balance
cochlea
part of the inner ear, organ hearing. long tapered coil structure. composed of vestibular membrane and the basilar membrane
organ of corti
sits on the basilar membrane
traduces pressure waves into action potentials
round window
flexible membrane at the end of the tympanic canal
flexions
traveling waves
cupula
gelatinous swelling enclosing a cluster of hair cell stereocilia
rhodospin
vertebrate visual pigment
consists of opsin(protein) and 11-cis-retinal (light absorbing functional group)
eye cups
organized photoreceptor cells
ommatidia
optical unit, with its own narrow-angle lens
sclera
spherical, fluid filled structure bounded by a tough connective tissue layer
cornea
at the front of the eye
formed by sclera
transparent to allow light in
iris
just inside the cornea
gives the eye its color
controls the amount of light that reaches the photoreceptor cells at the back of the eye
pupil
central opening of the iris
lens
crystalline protein
makes fine adjustments in the focus of images
retina
photosensitive layer
the two photoreceptors of the vertebrate retina
rod and cone cells (both modified neurons)
rod cells
highly light-sensitiveand perceive shades of gray in dim light
3 segments: outer, inner, and synaptic terminal
cone cells
function at high levels responsible for high-acuity color vision
fovea
area of the retina that receives light from the center of the visual field
optic nerve
formed by the axons of ganglion cells
ganglion cells
closest to the lens
fire action potentials
bipolar cells
connect ganglion cells to photoreceptors
rate of neurotransmitters released from the bipolar cells determines the rate that ganglion cells fire action potentials
horizontal cells
form synapses with neighboring photoreceptors and bipolar cells
amacrine cells
form local interconnections between bipolar cells and ganglion cells.
some highly sensitive to motion or to changing illumination
