Key Terms

Key Terms

sense of hearing
basilar membrane
stiff structure in the cochlea that indirectly anchors auditory receptors
bipolar neuron
neuron with two processes from the cell body, typically in opposite directions
abbreviated, unit of measurement of luminous intensity—brightness
describes a time cycle about one day in length
whorled structure that contains receptors for transduction of the mechanical wave into an electrical signal
weakly photosensitive, chromatic, cone-shaped neuron in the fovea of the retina that detects bright light and is used in daytime color vision
transparent layer over the front of the eye that helps focus light waves
region in the center of the retina with a high density of photoreceptors and which is responsible for acute vision
free nerve ending
ending of an afferent neuron that lacks a specialized structure for detection of sensory stimuli; some respond to touch, pain, or temperature
describes the nonhairy skin found on palms and fingers, soles of feet, and lips of humans and other primates
in the olfactory bulb, one of the two neural clusters that receives signals from one type of olfactory receptor
Golgi tendon organ
muscular proprioceptive tension receptor that provides the sensory component of the Golgi tendon reflex
sense of taste
also, farsightedness, visual defect in which the image focus falls behind the retina, thereby making images in the distance clear, but close-up images blurry
also, anvil, second of the three bones of the middle ear
inner ear
innermost part of the ear; consists of the cochlea and the vestibular system
pigmented, circular muscle at the front of the eye that regulates the amount of light entering the eye
sense of body movement
bony, hollow structure that is the most internal part of the ear; contains the sites of transduction of auditory and vestibular information
transparent, convex structure behind the cornea that helps focus light waves on the retina
also, hammer, first of the three bones of the middle ear
sensory receptor modified to respond to mechanical disturbance such as being bent, touch, pressure, motion, and sound
Meissner’s corpuscle
also, tactile corpuscle, encapsulated, rapidly-adapting mechanoreceptor in the skin that responds to light touch
Merkel's disc
unencapsulated, slowly-adapting mechanoreceptor in the skin that responds to touch
middle ear
part of the hearing apparatus that functions to transfer energy from the tympanum to the oval window of the inner ear
muscle spindle
proprioceptive stretch receptor that lies within a muscle and that shortens the muscle to an optimal length for efficient contraction
also, nearsightedness, visual defect in which the image focus falls in front of the retina, thereby making images in the distance blurry, but close-up images clear
neural processing of noxious, such as damaging, stimuli
airborne molecule that stimulates an olfactory receptor
sense of smell
olfactory bulb
neural structure in the vertebrate brain that receives signals from olfactory receptors
olfactory epithelium
specialized tissue in the nasal cavity where olfactory receptors are located
olfactory receptor
dendrite of a specialized neuron
organ of Corti
in the basilar membrane, the site of the transduction of sound, a mechanical wave, to a neural signal
one of the three bones of the middle ear
outer ear
part of the ear that consists of the pinna, ear canal, and tympanum, and which conducts sound waves into the middle ear
oval window
thin diaphragm between the middle and inner ears that receives sound waves from contact with the stapes bone of the middle ear
Pacinian corpuscle
encapsulated mechanoreceptor in the skin that responds to deep pressure and vibration
one of the small bump-like projections from the tongue
individual interpretation of a sensation; a brain function
substance released by an animal that can affect the physiology or behavior of other animals
cartilaginous outer ear
visual defect in which the image focus falls behind the retina, thereby making images in the distance clear, but close-up images blurry; caused by age-based changes in the lens
sense of limb position; used to track kinesthesia
small opening though which light enters
receipt of a signal, such as light or sound, by sensory receptors
receptive field
region in space in which a stimulus can activate a given sensory receptor
receptor potential
membrane potential in a sensory receptor in response to detection of a stimulus
layer of photoreceptive and supporting cells on the inner surface of the back of the eye
main photopigment in vertebrates
strongly photosensitive, achromatic, cylindrical neuron in the outer edges of the retina that detects dim light and is used in peripheral and nighttime vision
Ruffini ending
also, bulbous corpuscle, slowly-adapting mechanoreceptor in the skin that responds to skin stretch and joint position
semicircular canal
one of three half-circular, fluid-filled tubes in the vestibular labyrinth that monitors angular acceleration and deceleration
sensory receptor
specialized neuron or other cells associated with a neuron that is modified to receive specific sensory input
sensory transduction
conversion of a sensory stimulus into electrical energy in the nervous system by a change in the membrane potential
also, stirrup, third of the three bones of the middle ear
in the auditory system, hair-like projections from hair cells that help detect sound waves
superior colliculus
paired structure in the top of the midbrain, which manages eye movements and auditory integration
suprachiasmatic nucleus
cluster of cells in the hypothalamus that plays a role in the circadian cycle
food molecule that stimulates gustatory receptors
taste bud
clusters of taste cells
tectorial membrane
cochlear structure that lies above the hair cells and participates in the transduction of sound at the hair cells
tonic activity
in a neuron, slight continuous activity while at rest
also, tympanic membrane or ear drum, thin diaphragm between the outer and middle ears
sound frequencies above the human detectable ceiling of approximately 20,000 Hz
one of the five basic tastes, which is described as savory and which may be largely the taste of L-glutamate
vestibular sense
sense of spatial orientation and balance
sense of sight