Sensory Transduction Flashcards
where do most axons of retinal ganglion cells synapse?
lateral geniculate nucleus
how do intrinsically photosensitive retinal ganglion cells (ipRGCs) differ from the other types of photoreceptor cells – rods and cones?
ipRCGCs are able to respond to bright light even w/o input from rods and cones.
- involved in several non-imaging functions of visual system
receptive field of ganglion cells at retinal periphery is what compared to fovea (center of retina)?
much larger
what is the main response of the outer hair cells to depolarization?
outer hair cells contract, amplifying movement of basilar membrane.
what is the main response of inner hair cells to depolarization?
inner hair cells release NTs.
under scotopic conditions, human eye is maximally sensitive at
~500 nm
under photopic conditions, human eye is maximally sensitive at
~560 nm
S cone, M cone, L cone peak at what point?
~420 nm
~530 nm
~560
melanopsin peaks at what point of the spectrum?
~475 nm
dark adaptation
rods
light adaptation
cones
a condition that doesn’t have 2 of the 3 functional cone pigments
monochromacy (true color blindness)
absence of one functional pigment
dichromacy
shift in absorption spectrum of one pigment relative to normal
anomalous trichromacy
a light sensitive protein
melanopsin
functions of ipRGCs
- plays a role in maintaining circadian rhythm
- activity inhibits production of melatonin by pineal gland
- provides photic info to brain’s sleep-wake regulatory systems
- reports levels of ambient daytime illumination
olfactory receptors are _____/
neurons
taste receptors are ______.
modified epithelial cells
location of foliate papillae
folds along lateral surfaces of tongue
location of circumvallate papillae
posterior tongue
location of fungiform papillae
flat anterior surface of tongue
what kind of receptor cells are replaced throughout life?
olfactory receptor cells
how many genes does one olfactory receptor cell express?
only one gene is expressed by each receptor cell
function in detecting head rotation
3 semicircular canals
detect head position (gravity) and linear head movement
otolithic organs – utricle, saccule
What structures of the ear collect and focus waves into external auditory canal?
pinna/auricle and tragus
What connects the middle ear to the nasopharynx??
Eustachian tube
What does Eustachian tube do>
equalizes pressure on opposite side of tympanic membrane
Function of middle ear (an air filled chamber)
Serves to transfer vibrations of TM to the oval window
What is the function of tensor tympani and stapedius?
their contract dampens transfer of sound to inner ear
Which fluid filled compartment of cochlea does the air enter?
Scala vestibuli
What kind of fluid do scala tympani and scala vestibuli contain?
Perilymph
What kind of fluid does scala media contain?
Endolymph
What do mechanoreceptors monitor?
- BP in heart
- stretching of gut and intestines
- skin contact
- pressure on teeth
What layers of the skin are innervates by sensory receptors?
epidermis, dermis
What are 2 specialized types of free nerve endings?
Merkel discs
Hair follicle receptors
Rapidly adapting receptors
hair follicle receptors
slowly adapting receptors for light touch
merkel discs
Meissner’s corpuscles
respond to low frequency vibrations and light touch
Pacinian corpuscles
respond to deep pressure and high frequency vibrations
Ruffini’s corpuscles
slow adapting; respond to skin stretch
proprioceptors
detect notion and position of body through a stimulus produced w/in body
golgi tendon organ contains what kind of axons ?
Group Ib axons
muscle spindle contains what kind of axons?
There are 2.
Primary sensory endings - group Ia axons
Secondary sensory endings - group II axons
What kind of innervation does muscle spindle receive?
afferent and efferent innervation
Why do muscle spindles still get motor innervation when their primary function is sensory?
To continue to maintain control over sensitivity of the spindle
This is done with the help of gamma motor neurons, which cause intrafusal muscle fibers to contract in parallel w/ extrafusal fibers
What do tears have that help fight infection?
lysozymes, antibodies
What constantly secretes aqueous humor in the eyes?
ciliary epithelium
Aqueous humor
protein free ultrafiltrate of blood plasma
What is the importance of keeps the anterior portion of the eye slightly pressurized — ~20mmHg?
helps maintain eye shape
When ciliary my muscles are contracted, the lens are?
Rounded for close vision
when ciliary muscles are relaxed, lens are ______/
flattened for distant vision