Ear, Eye and Vestibular Anatomy

Question 1

Name the 2 cavities of the eyeball, their functions and what they are filled with

Answer 1

1) anterior segment, functions to maintain intra-ocular pressure, diffuses gases and nutrients, filled with aqueous humour
2) posterior segment, functions to maintain intra-ocular pressure and provides structural support, filled with vitreous humour

Question 2

What causes glaucoma and what are the effects, symptoms and treatments

Answer 2

glaucoma is caused by increased intra-ocular pressure where there is an imbalance between production and clearance of aqueous humour, leads to blindness, symptoms include seeing halos around lights and blurred vision, treatment: eye drops with prostaglandins, b blockers, diuretics

Question 3

describe the layers of the eyeball including position to one another and function

Answer 3

1) fibrous tunic
outer layer, provides structure
2) vascular tunic
middle layer, allows perception of light
3) retina
neural layer, high acuity area

Question 4

How many rods and cones per retina?

Answer 4

120 million rods, 6 million cones

Question 5

differentiate between the function of rods and cones

Answer 5

rods: high sensitivity, night vision, low acuity, vision in shades of grey
cones: low sensitivity, day vision, high acuity, colour vision

Question 6

What structure facilitates peripheral vision?

Answer 6

rods

Question 7

Outline the visual pathway.

Answer 7

retina -> ganglia -> optic nerve -> brain

Question 8

How is visual info sent to the occipital lobe?

Answer 8

via optic radiation

Question 9

What causes macular degeneration?

Answer 9

build up of waste products, blood vessels growing into retina or pigment epithelial cell death

Question 10

What layers are affected in retinal detachment?

Answer 10

tearing or separation of pigmented vascular layer and neural layers

Question 11

Name the 2 muscles in the iris and what it controls

Answer 11

pupillary dilator and constrictor, control how much light enters eye

Question 12

What is the cornea’s role in light refraction?

Answer 12

fixed focusing ability

Question 13

What is the lens’ role in light refraction?

Answer 13

adjustable focusing ability, flips image upside down

Question 14

Describe a myopic eye

Answer 14

eyeball too long, focal point in front of retina

Question 15

describe a hyperopic eye

Answer 15

eyeball too short, focal point behind retina

Question 16

Name the starting and finishing structures of the middle ear

Answer 16

tympanic membrane to oval window

Question 17

what is the function of the tympanic membrane?

Answer 17

to transmit sound to auditory ossicles

Question 18

Name the 3 parts of the auditory ossicles

Answer 18

malleus, incus, stapes

Question 19

which part of the auditory ossicles presses against oval window?

Answer 19

stapes

Question 20

Which structure allows equalisation of pressure in the middle ear?

Answer 20

auditory/pharyngotympanic tube

Question 21

Which structure does sound exit middle ear via?

Answer 21

oval
window

Question 22

Name the 2 main structures within inner ear

Answer 22

vestibular apparatus and cochlear

Question 23

List the 3 chambers of the cochlear.

Answer 23

scala vestibuli, cochlear duct, scala tympani

Question 24

Describe the pathway of sound from the inner ear to brain

Answer 24

sound pushes tympanic membrane -> pushes cochlear hair cells -> neural signal

Question 25

List the causes of conduction deafness

Answer 25

compacted ear wax, perforated ear drum, otis media (middle ear inflammation), osteoclerosis (overgrowth bony tissue fuses ossicles together)

Question 26

describe the causes of senso neural deafness

Answer 26

damage to neural structures, loss of hair cells, stroke, tumours, cochlear nerve degeneration

Question 27

What is the main function of the inner ear?

Answer 27

allows us to know where we are in space and if we are moving

Question 28

Describe the function of the semicircular canals in the inner ear

Answer 28

allow detection of rotational or angular acceleration or deceleration

Question 29

Describe the function of the otolith organs (utricle and saccule) in the inner ear

Answer 29

give us info about position of head relative to gravity and change of linear motion

Question 30

What lubricates the eyeball and how is it spread across eye?

Answer 30

lacrimal fluid spread by palpebrae