Special Senses: Visual, Vestibular & Auditory Systems

Question 1

What kind of light do rods and cones detect?

Answer 1

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

cones - detect color

Question 2

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

Answer 2

TRUE

Question 3

myopia

Answer 3

near sightedness; corrected with concave lens

Question 4

hyperopia

Answer 4

fat sightedness; corrected with convex lenses

Question 5

presbyopia

Answer 5

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

Question 6

glaucoma

Answer 6

• 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

Question 7

cataracts

Answer 7

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

Question 8

dry eye

Answer 8

• 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

Question 9

colour blindness

Answer 9

• usually poor red/green discrimination

- due to hereditary absence of red or green photoreceptors

Question 10

what does the parasympathetic nervous system do to pupil diameter?

Answer 10

constriction

Question 11

what does the sympathetic nervous system do to pupil diameter?

Answer 11

dilation

Question 12

what does the cochlea do?

Answer 12

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

Question 13

wernicke’s area

Answer 13

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

Question 14

the auditory cortex is found in what area?

Answer 14

temporal lobe

Question 15

deafness

Answer 15

complete hearing loss

Question 16

conductive deafness

Answer 16

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

Question 17

central deafness

Answer 17

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

Question 18

what is the vestibular system important for?

Answer 18

balance, controlling eye movements and posture; vestibular apparatus detects movements/acceleration and position by comparing input from the two sides

Question 19

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

Answer 19

1. semicircular canals

2. utricle and saccule (otolith organ)

Question 20

what nerve is associated with the vestibular system?

Answer 20

CN VIII - vestibulocochlear nerve

Question 21

semicircular canals

Answer 21

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

Question 22

otolith organ (utricle and saccule)

Answer 22

• detect the position of head relative to gravity
• changes in rate of linear motion in any direction

*gravity vector and linear acceleration

Question 23

vertigo

Answer 23

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

Question 24

nystagmus

Answer 24

• rhythmic vertical or horizontal eye movements triggered by vestibular stimulus