Flashcards in Special Senses: Visual, Vestibular & Auditory Systems Deck (24)
What kind of light do rods and cones detect?
rods - can't detect colour. Used under low light conditions
cones - detect color
True or false, the direction of processing in the eyeball is opposite the direction of light
near sightedness; corrected with concave lens
fat sightedness; corrected with convex lenses
loss of lens accommodation after age 40; corrected with reading glasses or bi or trifocals for those with myopia corrective lenses
- increased internal pressure in the eye
- may damage the nerve fibers exiting the eyeball via the optic nerve --> vision loss
- passages normally allowing drainage of fluid in eyes become blocked
- clouding of the normally clear lens --> blurred or distorted vision
- usually greater than age 55
- unknown cause
- either not enough tears, or tears of the wrong composition
- common with aging, antihistamines, oral contraceptives, antidepressants, dry climate, wind & dust or other health problems
- usually poor red/green discrimination
- due to hereditary absence of red or green photoreceptors
what does the parasympathetic nervous system do to pupil diameter?
what does the sympathetic nervous system do to pupil diameter?
what does the cochlea do?
specialized to change pressure waves from sound into a vibration of the basilar membrane
located at the junction of the temporal lobe; important in understanding speech
the auditory cortex is found in what area?
complete hearing loss
when there is a failure in the transduction of the sound wave in the middle or inner ear (bon calcification, basilar membrane damage)
when there is damage to the neural pathways such as the cochlear nerves, brainstem or cortex via lesion or disease
what is the vestibular system important for?
balance, controlling eye movements and posture; vestibular apparatus detects movements/acceleration and position by comparing input from the two sides
what are the 2 vestibular organs that are physically linked with the cochlea ?
1. semicircular canals
2. utricle and saccule (otolith organ)
what nerve is associated with the vestibular system?
CN VIII - vestibulocochlear nerve
3 canals at right angles to each other, detect rotational or angular acceleration or deceleration of the head (start and stop of spinning, somersault, turning head)
otolith organ (utricle and saccule)
- detect the position of head relative to gravity
- changes in rate of linear motion in any direction
*gravity vector and linear acceleration
- sensation of spinning
- can be of central or peripheral origin
- inappropriate activation of semicircular canal hair cells or imbalance between the 2 sides