L9.2. Visual, Auditory, and Vestibular Systems

Question 1

Where is the fovea centralis located?

Answer 1

Macula

Question 2

What is the function of the sclera?

Answer 2

protection & anchor for extraocular muscles

Question 3

What structure is also known as the “vascular layer” which nourishes the eye and regulates its temperature and volume?

Answer 3

Choroid

Question 4

Where does majority of total blood flow in the eye go?

Answer 4

Choroid - Choroidal Circulation (85%)

Question 5

This is the front portion of the eye and functions as the entry point of light.

Answer 5

Cornea

Question 6

This structure is pigmented and adjusts the pupil depending on the environment.

Answer 6

iris

Question 7

This is the hole where light passes.

Answer 7

Pupil

Question 8

What is the pupillary diameter?

Answer 8

3.7mm

Question 9

What is the function of the eye’s lens?

Answer 9

adjust focal length for accommodation

Question 10

What is the ideal intraocular pressure (IOP) at the Anterior and Posterior chambers of the eye?

Answer 10

12-18 mmHg

Question 11

This eye chamber is between the cornea and iris.

Answer 11

anterior

Question 12

The posterior chamber is between _________ & _________.

Answer 12

iris, lens

Question 13

Which layer in the retina are rods and cones found?

Answer 13

External Nuclear Layer

Question 14

Which layer in the amacrine cells found?

Answer 14

Internal Plexiform Layer

Question 15

This photoreceptor is sensitive to low intensity light.

Answer 15

Rods

Question 16

This photoreceptor is sensitive to high intensity light and is responsible for sharp vision and color discrimination.

Answer 16

Cones

Question 17

These neurons produce a “Dark image surrounded by light”.

Answer 17

Photoreceptors (1st order neuron), Bipolar Cells, Retinal Ganglion Cells (3rd order neurons)

Question 18

These cells produce a “Light image surrounded by dark”.

Answer 18

horizontal and amacrine cells

Question 19

This is a small indentation in the macula where vision is sharpest.

Answer 19

Fovea centralis

Question 20

What is known as the “natural blind spot” because it contains no rods or cornea?

Answer 20

optic disk

Question 21

What occurs in lesions at the optic chiasm?

Answer 21

bitemporal hemianopia (blindness at opposite sides for both eyes)

Question 22

Lesions at the optic nerve leads to what?

Answer 22

monocular blindness (complete blindness from one eye)

Question 23

Lesions at the optic tract leads to what?

Answer 23

homonymous hemianopia (blindness at same side for both eyes)

Question 24

This is also known as the outer ear.

Answer 24

Pinna

Question 25

This offsets pressure in the ear.

Answer 25

Eustachian Tube

Question 26

These compose the auditory ossicles.

Answer 26

malleus, incus, stapes

Question 27

Snail shaped bone containing the organ of corti

Answer 27

Cochlea

Question 28

This is the true organ of hearing and analyzes audio frequency.

Answer 28

Organ of Corti

Question 29

Fluid contained in membranous labyrinth.

Answer 29

Endolymph

Question 30

Fluid contained in bony labyrinth.

Answer 30

Perilymph

Question 31

Translates mechanical signals to electrical signals.

Answer 31

Hair cells

Question 32

What is the function of outer hair cells?

Answer 32

sensitivity and amplification of sound

Question 33

Modulates sensitivity of cochlear organ

Answer 33

Olivocochlear Bundle

Question 34

What auditory reflex responds as a startle/jerk of body (Stimulus: loud/sudden sound)?

Answer 34

General Acoustic Muscle

Question 35

What auditory reflex responds as constriction to dilation of pupils (Stimulus: loud/sudden sound)?

Answer 35

Cochleopupillary

Question 36

What auditory reflex responds as a blink (Stimulus: loud/sudden sound)?

Answer 36

Auropalpebral

Question 37

What auditory reflex responds as looking towards the direction of the sound (Stimulus: loud/sudden sound)?

Answer 37

auditory oculogyric

Question 38

Ringing or buzzing sound in ear, early sign of peripheral cochlear disease

Answer 38

Tinnitus

Question 39

What hearing loss affects outer or middle ear?

Answer 39

conduction hearing loss

Question 40

What hearing loss affects inner ear?

Answer 40

Sensorineural Hearing Loss

Question 41

receptor that detects horizontal acceleration

Answer 41

utricle

Question 42

receptor that detects vertical acceleration

Answer 42

saccule

Question 43

receives filaments of vestibular nerve

Answer 43

macula

Question 44

Calcium carbonate crystals that move along a gelatinous matrix. Detects changes in position and movement

Answer 44

otoliths

Question 45

Receptor that detects movement in sagittal plane (nodding)

Answer 45

anterior semicircular canal

Question 46

Receptor that detects movement in coronal plane

Answer 46

posterior semicircular canal

Question 47

Receptor that detects movement in transverse plane

Answer 47

lateral semicircular canal

Question 48

SuVN > LVN > VP nucleus of thalamus > cortex What is described?

Answer 48

Conscious perception

Question 49

Vestibulospinal tract responsible for limb and trunk posture

Answer 49

lateral vestibulospinal tract

Question 50

The medial vestibulospinal tract is involved in what reflex?

Answer 50

labyrinth righting reflex

Question 51

How long is the normal reflex response before it is declared as nystagmus?

Answer 51

30 seconds