Week 11 Flashcards

1
Q

What are the 3 components of the ear

A

external ear
middle ear
inner ear

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2
Q

What are the parts that make up the external ear

A

pinna, external acoustic meatus, tympanic membrane

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3
Q

What is the external acoustic meatus made up of

A

made of bone (inner part)and cartilage (outer part)

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4
Q

Describe features of the external ear

A

□ Has hairs to stop foreign bodies entering the acoustic meatus
□ Wax producing glands to produce foreign material that might enter the external acoustic meatus

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5
Q

What is the tympanic membrane

A

□ The tympanic membrane is the border between the external and middle ear
□ Tympanic membrane is thin
□ It is the ear drum

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6
Q

What is the function of the external ear

A

§ It channels sound through the external acoustic meatus to the tympanic membrane by gathering sound energy and focusing it on the eardrum

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7
Q

What are the parts of the middle ear

A

tympanic cavity
auditory ossicles
muscle of the ossicles

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8
Q

What are auditory ossicles

A

(found in tympanic cavity which leads back into the mastoid antrum where the mastoid air cells open) and act is a lever system to amplify sounds

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9
Q

What is the malleus

A

aka hammer
® Laterally attached to the tympanic membrane and medially it articulates with the incus via synovial joint

				® The extension that runs inferior to the neck and attaches to the central part of the tympanic membrane is the handle of the malleus
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10
Q

What is the function of the malleus

A

® It receives sound from tympanic membrane which it transmits to the incus

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11
Q

What is the function of the incus

A

aka anvil

® Connects the malleus and stapes

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12
Q

What is the stapes

A

® Articulates with the incus laterally and allows transmission of vibrations to the vestibule of the internal ear

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13
Q

What is the function of the middle ear

A

§ Transforming a high amplitude low force sound wave into a low amplitude high-force vibration and transmitting it to the internal ear

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14
Q

What is the internal ear made up of

A

bony labyrinth

membranous labyrinthe

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15
Q

What is the bony labyrinth made up of

A

vestibule, semi-circular canal, cochlea

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16
Q

What is the cochlea

A

where hearing is perceived and the semi-circular canal is involved in hearing, space, balance and spatial awareness

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17
Q

What is the function of the internal ear

A

§ Bony labyrinth supports its membranous counterparts

§ Gives info on position of the head, movements of the head and providing hearing information

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18
Q

What is the internal ear supplied by

A

vestibulocochlear nerve

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19
Q

What is sound

A

is a compression and refraction of air and it causes the tympanic membrane to vibrate. They transmit the vibrations by being moved by the muscles of the middle ear and the it causes fluid inside the inner ear to move stimulating the hair cells

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20
Q

If there is a loud sound what is the protective mechanism

A

the tensor tympani contracts and holds the handle of the malleus and restricts the movement of the tympanic membrane so there is less vibrations and it is supplied by the branches of trigeminal
• The stapedius muscle can contract in the event of loud noises and it holds and reduces movement of the stapes and is controlled by the facial nerve - facial nerve palsy may cause sounds/noises to appear louder as the stapedius is not working

21
Q

What is chronic otitis media

A

○ Infection of the middle ear that persists
○ A perforated tympanic membrane allows the infection to drain into the external acoustic meatus and pus leaks out of the ear

22
Q

What is chronic otitis media with effusion

A

○ Looks like small bubbles on tympanic membrane
○ Series of sore throats causes enlargement of tubal tonsils which blocks off the opening to the auditory tube meaning air cant get into the middle ear and mucus builds up causing deafness
○ The treatment is to wait until resolution or small incision made in tympanic membrane and a ventilation tube is inserted

23
Q

Describe the iris

A

○ Meets the lower lid but is covered slightly by the upper lid
○ Diaphragm that regulates the size of the pupil to control the amount of light that enters the eye
Iris is pigmented and can get different colours and we see this through the transparent cornea which is covering i

24
Q

What is the conjunctiva

A

○ Mucous membrane that covers the sclera which is the outermost coat of the eye

25
Q

What are eyelashes

A

○ Slightly curved hairs
○ Curvature stops the eyelashes sticking together when they are closed and they are on the parts that are square but not on the rounded medial parts

	○ Arise from hair follicles
26
Q

What are the function of eyelashes

A

○ Stop foreign objects entering the eye

27
Q

What happens if the lash follicles becomes infected

A

○ Sometimes the lash follicles can become infected and is called a stye

28
Q

What are meibomian glands

A

○ Oil secreting glands in eyelids and are slightly further back and sometimes there may be a blockage resulting in a meibomian cyst resulting in a localised thickening
○ Oily secretion stops tears from falling onto the face

29
Q

What is the impact of hyperthyroidism on the eye

A

not uncommon for there to be excess fat deposition in the orbit pushing the eyes forward and the lid cuts across the upper edge of the iris or you may even see the border

30
Q

Where is the lacrimal gland

A

○ Sits in front part of upper orbit slightly extended into the eyelid
○ Small flat gland which has little ducts draining into conjunctival sac which is a recess between the front of the eye and inside of the eye

31
Q

What is the reason for blinking

A

○ Blinking ensures that tears cover the eye and keep the cornea moist

32
Q

What is the lacrimal punctum

A

○ Little hole medially that feeds into duct system

○ Faces into the tears

33
Q

What are the ducts that feed into the lacrimal punctum

A

○ The ducts it feeds into are called lacrimal canaliculus

34
Q

What is the lacrimal sac

A

○ On the medial part of the orbit, lying up against the orbital wall and medial side is the lacrimal sac and these ducts feed into the sac that lies on the most medial part of the orbit
○ It goes into the nasolacrimal duct which opens into the inferior meatus of the nasal cavity

35
Q

When may the lacrimal canaliculi be damaged

A

facial trauma

36
Q

What is the frontal nerve

A

○ Branch of the ophthalmic nerve

37
Q

What does the frontal nerve split into

A

supra orbital

supra trochlear

38
Q

What is the supra orbital nerve

A

□ Bigger lateral branch
□ Provides sensation to forehead and front of the scalp as far back as the highest point of the head (vertex) and exits via supra orbital notch

39
Q

What is the supra trochlear nerve

A

□ Slightly smaller branch
□ More localised distribution - a little bit of the skin around the medial end of the eyelid and bit of the forehead near the midline

40
Q

Where is the levator palpebral superioris seen

A

○ Deep to frontal nerve

Takes origin from bone in back of the orbit and runs forward where it attaches to the eyelid

41
Q

What is the function of the levator palpebral superioris muscle

A

○ Holds the upper eyelid open and it is skeletal and smooth muscle
○ Skeletal muscle is supplied by oculomotor and the smooth muscle is supplied by sympathetic supply
○ Hornets syndrome is droopy eyelid

42
Q

What is the superior rectus

A

○ Sits below the levator palpebrae superioris muscle
○ Thin
○ Helps move the pupil up the way
○ Also supplied by CN3

43
Q

What is the lateral rectus

A

○ Turns eye out the way

○ Supplied by abducens

44
Q

What is the ethmoidal sinuses

A

○ In the medial wall
○ Lined by mucosa
○ Looks bubbly

45
Q

What is the superior oblique

A

○ Coming from the roof of the orbit at the back
○ Tiny nerve divides into two to supply it - the trochlear nerve which comes from under the orbital roof at the back of the orbit

46
Q

What does the tendon for superior oblique run through

A

the trochlear

47
Q

What happens when the superior oblique contracts

A

it pulls the tendon which pulls the eyeball towards it and the superior oblique is attached to the back of the eye so it is pulled up and the pupil tends to go down at the front

48
Q

What is the arrangement of the superior oblique

A

○ Has a pully arrangement (fibrous material) and the tendon uses this and changes direction and then it fans out as it heads out towards the eyeball itself which is down below the Levator and superior rectus muscle