H&N week 11- Ear and Eye

Question 1

Label this diagram of the ear

Answer 1

Question 2

Label this diagram of the middle ear.

Answer 2

Question 3

Label this diagram of the inner ear.

Answer 3

Question 4

Discuss the 3 parts of the ear

Answer 4

External ear gathers soundwaves

It is made of the aurcicle and the external aucoustic meatus.

Middle ear- magnifies the sound vibrations

This contains air and 3 ossciles (malleus, incus and stapes)

Inner ear- For hearing and balance.

This contains the semi-circular canals and cochlea

Question 5

Where is the chordae tympani found?

Answer 5

Inside the tympanic membrane.

Question 6

Discuss the safety mechanisms of the external ear.

Answer 6

Hairs- to prevent bodies entering

Ceruminous glands- to produce wax.

Question 7

What is otitis externa?

Answer 7

Inflammation of the skin lining.

Question 8

Discuss the auricle

Answer 8

Function: gathers sound and sends it into the aucoustic meatus

Made of: A skeleton of elastic cartilage and lined with skin.

It is also known as the Pinna.

Question 9

What is the external aucoustic meatus?

Answer 9

A bony canal running from the outer ear to the middle ear.

The outer part of the canal is made of cartilage and the inner part is made of bone.

Question 10

What is the tympanic membrane

Answer 10

A thin membrane in the middle ear that is made of skin and collagen.

It sits under tension and vibrates when soundwaves come through.

Question 11

What is the umbo?

Answer 11

The most concave part of the tympanic membrane.

Question 12

How is the ear protected from loud sounds?

Answer 12

Tensor tympani muscle

• A tendon attached to the handle of the malleus
• it contracts to hold the malleus more steady, reducing vibrations
• Supplied by CN5

Stapedius muscle.

• It contracts and anchors the stapes to reduce movement
• Supplied by CN7

Question 13

What is the tympanic cavity ?

Answer 13

Where you find the ossicles.

Question 14

What is the Malleus?

Answer 14

A hammer shaped bone which attaches to the central part of the tympanic membrane.

Question 15

What is the incus?

Answer 15

An anvil shaped bone which has a long process that articulates with the stapes

Question 16

What is the stapes?

Answer 16

A bone that is shaped like a horse stirup (food rest) whcih fits into an inner window that seperates the middle and inner ear.

Question 17

How does the stapes magnify sounds?

Answer 17

the tympanic membrane vibrates causing the food plate of the Stapes to move in and out.

This causes the movement of fluid.

Question 18

How are sounds converted to electrical impulses?

Answer 18

the movement of fluid to the inner ear causes the movement of special receptor cells (hair cells with long cilia) and convert to electrical impulses.

Question 19

What is chronic otitis?

Answer 19

A middle ear infection.

Sometimes the patient’s tympanic membrane can break down causing pus to go to the external ear.

Question 20

What is glue ear?

Answer 20

When there is fluid in the middle ear (also known as chronic Otitis media with effusion.

Question 21

Discuss the clinical relevance of a throat infection

Answer 21

The auditory tube allows infections to pass to the nose from the oral cavity.

This passage causes the lymphoid tissue around the aduitory tube to get bigger and block air getting into the middle ear.

This causes goblet cells to produce more mucous and prevents the ossicles from moving.

Therefore causing hearing problems.

Question 22

What is the function of the cochlea?

Answer 22

this picks up electrical impulses.

Question 23

Discuss the two windows of the middle ear:

Answer 23

Fenestra vestibuli-

An oval window that moves in and out, pushing on the fluid. This puts pressure on the water.

Fenestra Cochleae-

The round window which has a membrane in it.

As fluid moves into the inner ear, this membrane bulges to compensate.

Question 24

Discuss the semi-circular canals

Answer 24

These are involved with movement of the head, balance and the position of the head within the space.

Question 25

Label this diagram of the eye

Answer 25

Question 26

Label this diagram of the disection of the orbit from above.

Answer 26

Question 27

What is the cornea?

Answer 27

A transparent dome covering the iris.

Question 28

Discuss the eyelashes

Answer 28

These arise from hair follicles along the outer edge of the eyelid. The eye lashes are slightly curved to prevent them sticking together when you close your eye.

Question 29

What is the clinical name for an infected eyelash follice?

Answer 29

A stye.

Question 30

WHat is the sclera?

Answer 30

The white of the eye

Question 31

What is the conjunctiva?

Answer 31

A mucous membrane which covers the white of the eye

Question 32

What is an infection of the conjunctiva called?

Answer 32

Conjunctivitis.

Question 33

What is the iris?

Answer 33

The coloured part of the eye that is partially covered by the upper eyelid. Function- it is a diaphragm that controls the amount of light that enters the eye by regulating the pupil size.

Question 34

Discuss the eye of a thryoid patient

Answer 34

They show opthalmopathy - There is excessive fat deposition in the orbit which pushes the eye forward. - The upper eyelid does not cross the upper iris - You can see white all around the eye.

Question 35

What is the pupil?

Answer 35

The opening into which the light enters the eye.

Question 36

What is the lacrimal carnucle?

Answer 36

A fleshy papilla found in the medial corner of the eye.

Question 37

What are the meibomian glands?

Answer 37

Glands found on the eyelid that produce oil secretions that keep the tears between the eyelid and the front of the eye (preventing tears spilling onto your face)

Question 38

What is the lacrimal sac?

Answer 38

A mucosa lined sac which carries tears down from the orbit into the nasal cavity.

Question 39

What is the lacrimal canaliculus?

Answer 39

The duct which takes the tears away. This is lined by mucous membrane. The tears are drawn into the duct by papillary action and fed into the lacrimal sac.

Question 40

What is the lacrimal puncture?

Answer 40

The opening of the lacrimal duct which drains the tears away.

Question 41

Discuss the lacrimal gland

Answer 41

This is found on the front part of the orbit (on the distal side) This produces tears and has lot of little ducts that drain into the conjunctival sack

Question 42

What is the conjunctival sack?

Answer 42

A recess between the front of the eye and the inside of the eyelid.

Question 43

Discuss the lateral rectus muscle

Answer 43

This is supplied by the abducens muscle and moves the eye to the side.

Question 44

What is the levator palpebral superiorous

Answer 44

This is a mixture of skeletal and smooth muscle that raises the upper eyelid. Skeletal muscle is supplied by the oculomotor nerve Smooth muscle is supplied by the sympathetic supply.

Question 45

Discuss the superior oblique muscle

Answer 45

This comes from the roof of the orbit and is supplied by CN4 (trochlea nerve. ) It gives way to atendon which goes through the trochlea

Question 46

Discuss the tendon of the superior oblique muscle

Answer 46

This changes direction after the trochlea, becomes thinner and stretches out to attach to the eyeball itself.

Question 47

What is the trochlea?

Answer 47

This is a pully used to change the directon of the tendon of the superior oblique.