Visual & Auditory Systems Flashcards
What is the spectrum of visible light
400-700 nm
High acuity vision is possible due to the __________, a tiny part of the retina
Fovea
Photoreceptors (Rods) can detect ______ photon of light
one
Light sensitive receptor protein contained within the outer segment of a rod photoreceptor
Rhodopsin
Activated rhodopsin, once it binds a photon of light, initiates a cascade of biochemical reactions that is a (fast/slow) process; why it takes time to adapt to darkness
Slow
Type of photoreceptor; “moonlight/night vision” receptors; only in peripheral retina, mediate LOW acuity vision; responds to a SINGLE photon
Rods
Type of photoreceptor; “daylight” receptors; mainly in fovea; mediate HIGH acuity vision; provides color vision (3 types); requires MANY photons
Cones
The Optic Disc at the back of the eye is (dark/light) in appearance
Light (also can see lots of arteries radiating from it)
The Fovea at the back of the eye is (dark/light) in appearance
Dark
Swollen appearance of the Optic Disc seen on fundoscopic exam; usually due to increased ICP because of a mass (like a brain tumor); visual acuity is NOT affected, although blind spot may be enlarged
Papilledema
Papilledema will result in a decreased visual acuity (True or False)
False; visual acuity is NOT affected, but blind spot may be enlarged
The (left/right) visual field maps to the right hemisphere
Left
The (left/right) visual field maps to the left hemisphere
Right
The Visual pathways will synapse in what portion of the Thalamus
Lateral Geniculate Nucleus
The medial side of the left retina will eventually have it’s signal sent to the (left/right) hemisphere
Right hemisphere (crosses at Optic Chiasm)
The lateral side of the left retina will eventually have it’s signal sent to the (left/right) hemisphere
left hemisphere (doesn’t cross at Optic Chiasm)
Upper occipital gyrus that receives signals from your LOWER visual field
Cuneus
*flips on it’s way to the Occipital lobe
Lower occipital gyrus that receives signals from your UPPER visual field
Lingula
*flips on it’s way to the Occipital lobe
Number of cycles per second
Frequency/pitch
In regards to frequency, the higher the frequency means (shorter/longer) wavelengths
Shorter wavelengths
Range of frequencies that a human can hear
20-20,000 Hz
Function of the Outer Ear
Collection of sound waves to the tympanic membrane
*aided by the shape of the pinna
Function of the Middle Ear
Transfer and AMPLIFY the vibratory movements of the tympanic membrane via 3 ossicles arranged in series
Function of the Inner Ear
Contains the Cochlea to tranduce sound energy to neural energy
The Eustachian tube is continuous with which portion of the ear
Middle Ear
Pattern of the Middle Ear Bones (ossicles)
Malleus (“hammer”)–> Incus–> Stapes (“stirrup”)
The Middle Ear Bones transmit physical energy to the (oval/round) window of the Cochlea
Oval window
Specialized polarized epithelial cells modified as hearing receptors in Cochlea; has hair-like bundles composed of stereocilia; part of the Organ of Corti
Hair cells
Mechanism lying on the basilar membrane of the Cochlea membranes; contains hair cells and a tectorial membrane essential for sound detection and transduction into neural signals
Organ of Corti
Which middle ear ossicle presses against the Oval window
Stapes
Stereocilia (part of Hair Cells) are bathed in ________________ which is high in Potassium (K+)
Endolymph
When sterocilia bend (toward/away from) the Kinocilium, what two ions enter the cell
Toward; K+ and Ca++
The narrow end of the Cochlea membrane vibrates in response to (high/low) frequency
High
*near the oval window at the beginning
The wide end of the Cochlea vibrates in response to (high/low) frequency
Low
*furthest away from oval window
From the ear, CN 8 axons synapse in the medulla at the
cochlear nuclei
Auditory pathway becomes bilateral after what point?
Synapse in cochlear nuclei in the medulla
Auditory information from the Cochlea synapses at what nucleus in the Thalamus
Medial Geniculate Nucleus (MGN)
The Primary Auditory Cortex is on what part of the Temporal lobe
Medial face of Lateral fissure
How is the primary auditory cortex organized in the temporal lobe?
tonotopically organized
- Basilar membrane of cochlear is tonotopically organized as well.
What frequency goes first in acquire deafness?
high frequency (like in unvoiced consonants = f, p, s, t)
What medications can cause acquired deafness?
aminoglycoside antibiotics (-mycin)
- gentamycin, streptomycin, neomycin
What is aging-related progressive sensorineural hearing loss?
presbycusis
In presbycusis, what frequency is affected first and why?
high-frequency (consonants); the functioning of the hair cells in the BASE of basilar membrane is lost first.
