BMS271 - Eye & Ear

Question 1

Eyelids (palpebrae)

Answer 1

connective + muscle tissue (muscle opens eyes = levator palpebrae)
lubricated by tarsal glands
closed by orbicularis oculi

Question 2

Conjunctiva

Answer 2

transparent mucous membrane
covers inner surface of eyelids and anterior eyeball
Conjunctivitis – pink eye, contagious, bacterial, irritation, mechanical, injury

Question 3

Lacrimal apparatus

Answer 3

lacrimal gland (superiolateral corner)
lacrimal canaliculi + sac (inferiomedial)
Lateral to medial

Question 4

Extrinsic eye muscles

Answer 4

superior, inferior, lateral and medial rectus

superior and inferior oblique

Question 5

Anatomy of the Eye

Answer 5

Three layers or tunics:

fibrous, vascular and nervous

Question 6

Fibrous tunic

Answer 6

sclera (white of the eye)

cornea

Question 7

Sclera

Answer 7

dense collagenous connective tissue which muscles attach to, firm, posterior 5/6ths of eye

Question 8

Cornea

Answer 8

clear, avascular connective tissue, allows light to enter, refracts (bends) light rays, injury prone

Question 9

Vascular tunic

Answer 9

choroid, ciliary body and iris

Question 10

Choroid

Answer 10

underneath sclera, thin membrane, black

Question 11

Ciliary body

Answer 11

smooth muscle sphincter attached to lens via suspensory ligaments

Question 12

Iris

Answer 12

coloured, smooth muscle, regulates pupil size

Question 13

Neural tunic

Answer 13

retina

macular lutea

Question 14

Compartments and Lens

Answer 14

The eye is divided into two compartments named the anterior and posterior segments
They are separated by the lens
Lens = transparent, biconvex, epithelial tissue
The anterior segment is filled with fluid called aqueous humor, and is further divided into anterior and posterior chambers (separated by iris/pupil)
The posterior segment is filled with vitreous humor (jelly) and is much larger than the ant. seg.
These fluids help maintain the shape of the eye

Question 15

Anatomy of Hearing

Answer 15

External, middle and inner ears

Question 16

External ear

Answer 16

auricle
external acoustic meatus 
tympanic membrane
Tragus = little bit that does nothing 
Auricle or pinna = ear
Lobule = ear lobe

Question 17

Middle ear

Answer 17

Middle ear

• air filled space connected to pharyngotympanic tube
• ossicles = malleus, incus, stapes
• Middle ear separated from inner ear by round and oval windows
• Oval window deep to stapes

Question 18

Inner ear

Answer 18

bony and membranous labyrinths (canals in bone filled with fluid, membranes and receptors)
Cochlear
Semicircular canals

Question 19

Hearing

Answer 19

Soundwaves arrive at the tympanic membrane and cause it to vibrate
This in turn causes vibration of the malleus (hammer), incus (anvil) and stapes (stirrup)
The stapes is attached to the oval window of the cochlea (snail shell)
Vibration at the oval window causes vibration in the fluid inside the cochlea, which causes deformation (change in shape) of the basilar membrane
Hair cells (sensory receptors) in the membrane send action potentials in response to this deformation

Question 20

Hearing loss

Answer 20

Conductive – problem with getting sounds waves, external, middle ear

Sensory neural loss – damage to nerve or cochlear