Sensory systems Flashcards
sensory transduction
covers a stimulus into an electrical signal in the nervous system
somatosensation
vestibular sensation
proprioception
kinesthesia
vestibular sensation
spatial orientation and balance
proprioception
positions of bones, joints, and muscles
kinesthesis
limb movement and tracking
simple receptors for general senses
modified dendritic ending of sensory neurons
tactile sensations
temperature
pain
muscle sense
receptors for special senses
vision
hearing
equilibrium
smell
taste
sensory transduction overview
stimulus
reception
ion channels affected- changes in electrical potential
positive change in membrane potential depolarizes the neuron. negative change hyperpolarizes the neuron
neuron will fire AP- if polarization change is sufficient(crossing a threshold)
reception
activation of sensory receptors
encoding and transmission of sensory info
type of stimulus
location in the receptive field
duration and relative intensity
intensity is encoded by
rate of action potentials(frequency)
number of receptors activated(population
perception
with the exception of olfaction, all sensory signals are routed from the thalamus to final processing regions in the cortex of the brain
somatosensation
includes all sensation received from the skin, mucous membranes, limbs and joints
receptor types
thermoreceptors
pain receptors
chemoreceptors
mechanoreceptors
tactile
proprioceptors
baroreceptors
tactile receptors/ receptor types in skin
merkel’s disks
meissners corpuscles
ruffini endings
pacinian corpuscles
krause end bulbs
merkel’s disks
unencapsulated, respond to light touch
meissner’s corpuscles
respond to touch and low-frequency vibration
example –> fingertips
ruffini endings
detect stretch, deformation within joints, and warmth
pacinian corpuscles
detect transient pressure and high-frequency vibration
krause end bulbs
detect cold
olfaction
in the human olfactory system, bipolar olfactory neurons extend from the olfactory epithelium, where olfactory receptors are located, to the olfactory bulb
odorants enter nose and bind to receptors
single transduction–> APs to olfactory bulb–> brain via olfactory nerve–> perception of smell
5 primary tastes
salty
sweet
sour
bitter
umami
taste
each taste has only one corresponding type of receptor
each is specific to its stimulus
transduction of the five tastes happens through different mechanisms that reflect the molecular composition of the tastant
hearing
cochlea
balance
vestibule
sound
outer ear to the middle ear
bounded on its exterior by the tympanic membrane
middle ear
contains three bones called ossicles that transfer the sound wave to the oval window
oval window
the exterior boundary of the inner ear
organ of corti
organ of sound transduction
inside the cochlea
sound waves
wavelength corresponds to pitch
amplitude of the wave corresponds to volume
sound wave transduction
a sound wave causes the tympanic membrane to vibrate
the vibration is amplified as it moves across the malleus, incus and stapes
the amplified vibration is picked up by the oval window causing pressure waves in the fluid of the scala vestibuli and scala tympani
hair cells
mechanoreceptor
stereocilia on apical surface
stereocilia
tethered together by proteins
open ion channels when the array is bent toward the tallest member of their array
closed when the array is bent toward the shortest member of their array
5 vestibular receptor organs in the inner ear
utricle
saccule
three semicircular canals
vestibular information
hair cells in the utricle and saccule lie below a gelatinous layer, with their stereocilia projecting into the gelatin
embedded in this gelatin are calcium carbonate crystals– like tiny rocks
signal transduction similar to hearing
when hair cells are bent–> APs to brain
direction of bending in semicircular canals gives direction of head
cornea
transparent layer of the eye
lens
transparent convex structure behind the cornea
iris
muscular ring around the pupil
regulates the amount of light entering the eye
photoreceptors
located in the retina
inner surface of the back of the eye
photoreceptors
rods and cones
rods
strongly photosensitive
located in the outer edges of the retina
detect dim light
used primarily for peripheral and nighttime vision
cones
weakly photosensitive
located near the center of the retina
respond to bright light
primary role is color vision
transduction of light
rhodopsin, the photoreceptor in vertebrates, has two parts
- the trans-membrane protein opsin
- retinal
when light strikes retinal, it changes shapes from a cis to a trans form
signal is passed to a G-protein called transducin
transducin activates phosphodiesterase converts cGMP to GMP
- closes sodium channels
membrane becomes hyperpolarized
hyperpolarized membrane does not release glutamate to the bipolar cell
- release of tonic inhibition
APs –> ganglion cells–> optic nerve –> brain
audition
sense of hearing
auricle
cartilaginous outer ear
basilar membrane
stiff structure in the cochlea that indirectly anchors auditory receptors
candela
unit of measurement brightness
cochlea
a whorled structure that contains receptors for the transduction of the mechanical wave into an electrical signal
fovea
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 the detection of sensory stimuli; some respond to touch, pain, or temperature
glabrous
describes the non-hairy skin found on palms and fingers, soles of feet, and lips of humans and other primates
gustation
sense of taste
incus
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
iris
pigmented, circular muscle at the front of the eye that regulates the amount of light entering the eye
kinesthesia
sense of body movement
labyrinth
bony, hallow structure that is the most internal part of the ear; contains the sites of transduction of auditory and vestibular information
lens
transparent, convex structure behind the cornea that helps focus light waves on the retina
malleus
also hammer; first of the three bones of the middle ear
mechanoreceptor
sensory receptor modified to respond to mechanical disturbance such as being bent, touch, pressure, motion, and sound
meissner’s corpuscle
tactile corpuscle; encapsulated, rapidly-adapting mechanoreceptor in the skin that responds to light touch
merkels disk
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
nocieception
neural processing of noxious (such as damaging) stimuli
odorant
airborne molecule that stimulates an olfactory receptor
olfactory bulb
neural structure in the vertebrate brain that receives signals from olfactory receptors
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
ossicle
one of the three bones of the middle ear
outer ear
part of the ear that consists of the auricle, ear canal, and tympanum and which conducts sound waves into the middle ear
oval window
thin diaphragm between the middle and inner ear 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
papilla
one of the small bump-like projections from the tongue
perception
individual interpretation of a sensation; a brain function
proprioception
sense of limb position; used to track kinesthesia
pupil
small opening through which light enters
reception
receipt of a signal like light or sounds 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
retina
later of photoreceptive and supporting cells on the inner surface of the back of the eye
rhodopsin
main photopigment in vertebrates
rod
strongly photosensitive, achromatic, cylindrical neuron in the outer edges of the retina that detects dim light and is used in peripheral and nightime vision
ruffini ending
also bulbous corpuscle; slowly-adapting mechanoreceptor in the skin that responds to skin stretch and joint position
semicircular canal
one of the three half-circular, fluid-filled tubes in the vestibular labyrinth that monitors the 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
conversation of a sensory stimulus into electrical energy in the nervous system by a change in the membrane potential
stapes
also, stirrup; third of the three bones of the middle ear
stereocilia
in the auditory system, hair-like projections from hair cells that help detect sound waves
tastant
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
tympanum
also tympanic membrane or ear drum; thin diaphragm between the outer and middle ears
ultrasound
sound frequencies above the human detectable ceiling of approximately 20,000 hz
umami
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
