Special Senses: Visual, Vestibular & Auditory Systems Flashcards Preview

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Flashcards in Special Senses: Visual, Vestibular & Auditory Systems Deck (24)
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1

What kind of light do rods and cones detect?

rods - can't detect colour. Used under low light conditions

cones - detect color

2

True or false, the direction of processing in the eyeball is opposite the direction of light

TRUE

3

myopia

near sightedness; corrected with concave lens

4

hyperopia

fat sightedness; corrected with convex lenses

5

presbyopia

loss of lens accommodation after age 40; corrected with reading glasses or bi or trifocals for those with myopia corrective lenses

6

glaucoma

- 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

7

cataracts

- clouding of the normally clear lens --> blurred or distorted vision
- usually greater than age 55
- unknown cause

8

dry eye

- 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

9

colour blindness

- usually poor red/green discrimination
- due to hereditary absence of red or green photoreceptors

10

what does the parasympathetic nervous system do to pupil diameter?

constriction

11

what does the sympathetic nervous system do to pupil diameter?

dilation

12

what does the cochlea do?

specialized to change pressure waves from sound into a vibration of the basilar membrane

13

wernicke's area

located at the junction of the temporal lobe; important in understanding speech

14

the auditory cortex is found in what area?

temporal lobe

15

deafness

complete hearing loss

16

conductive deafness

when there is a failure in the transduction of the sound wave in the middle or inner ear (bon calcification, basilar membrane damage)

17

central deafness

when there is damage to the neural pathways such as the cochlear nerves, brainstem or cortex via lesion or disease

18

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

19

what are the 2 vestibular organs that are physically linked with the cochlea ?

1. semicircular canals
2. utricle and saccule (otolith organ)

20

what nerve is associated with the vestibular system?

CN VIII - vestibulocochlear nerve

21

semicircular canals

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)

*rotational movements

22

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

23

vertigo

- sensation of spinning
- can be of central or peripheral origin
- inappropriate activation of semicircular canal hair cells or imbalance between the 2 sides

24

nystagmus

- rhythmic vertical or horizontal eye movements triggered by vestibular stimulus