Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Eye and CNS case discussion > Tear film, the globe and cornea > Flashcards

Tear film, the globe and cornea Flashcards

1
Q

What are the 3 components to tear film?

A

Aqueous layer
Mucin layer
Lipid layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What produces the lipid layer of tear film? Where are these located?

A

Meibomian/tarsal glands

Tarsal plate in eyelids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the function of the lipid layer of tear film?

A

Reduces evaporation

Hold tears within palpebral fissure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The mucin layer is mixed into which other layer? What does it do?

A

Mixed into aqueous layer

Helps stabilise it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What produces the mucin layer of tear film?

A

Goblet cells in conjunctiva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What produces the aqueous layer of tear film?

A

Lacrimal and nicititans gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the function of the aqueous layer?

A

Lubricate, protect and provide nutrition

For corneal, limbal and conjunctival epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What control is tear film under? (Nervous system)

A

Autonomic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What nerve mainly supplies tear film production?

A

Lacrimal nerve of ophthalmic branch of trigeminal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where is the main lacrimal gland located?

A

Dorsolateral orbit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do the lacrimal puncture open into?

A

Lacrimal canaliculi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What encircles the lacrimal canaliculi and why?

A

Obicularis oculi

Pumps tears along tear duct system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where do the lacrimal canaliculi meet? Where is this located? Which species is this poorly developed?

A

Lacrimal sac
Located in lacrimal fossa of lacrimal bone
Poorly developed lacrimal bone in cat and dog

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where does the lacrimal sac empty into? Where does this empty into?

A

Nasolacrmal duct

Nasal cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The obicularis oculi muscle controls blinking. What is the function of blinking?

A

Spread tear film

Help drain nasolacrimal gland (pumps tears along duct system)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give 3 reasons why rabbits have a vulnerable lacrimal drainage system

A

Runs over cheek teeth (dental disease damages nasolacrimal duct)
Only one lacrimal punctual
2 sharp bends in the duct = block easily

17
Q

The globe/eyeball shape varies between species. What shape globe do cattle and horses have?

A

Slightly flattened

18
Q

What are the 3 layers to the globe/eyeball?

A

Fibrous layer
Uvea
Neural layer

19
Q

What is the function of the fibrous layer of the globe?

A

Supports shape of eyeball

20
Q

What is the function of the uvea?

A

Provides nutrition

Alters light transmission

21
Q

What is within the neural layer of the globe?

A

Retina = light detection

22
Q

What divides the eye into anterior and posteior segments?

A

Lens

23
Q

The anterior segment of the globe is further divided into anterior and posterior chambers. What divides these?

A

Iris

24
Q

What is the outermost layer of the front of the eye? What does it do? Does it have conjunctiva?

A

Cornea

Dome shape focuses vision No

25
Q

What are the 4 layers of the cornea?

A

Anterior epithelium
Stroma
Descemet’s membrane
Endothelium

26
Q

What does the anterior epithelium of the cornea contain?

A

Squamous cells at surface
Columnar cell at base
Lots of pain receptors

27
Q

What does the stroma of the cornea contain?

A

Collagen fibrils - form lamellae
Keratocytes
Proteoglycans
Pressure receptors

28
Q

What gives the cornea its clarity?

A

Collagen fibrils that form lamellae in the stroma

29
Q

What produces Descemet’s membrane?

A

Endothelium

30
Q

What dess the endothelium of the cornea do?

A

Produces Descemets membrane

Maintains stromal hydration

31
Q

Is the endothelium of the cornea able to regenerate?

A

No

Except in rabbit

32
Q

Damage to the cornea is painful as it is highly innervated. What nerve innervates it?

A

CN V (trigeminal)

33
Q

Where are pain receptors and pressure receptors in the cornea?

A

Pain receptors in anterior epithelium

Pressure receptors in stroma

34
Q

How does damage to the epithelium or endothelium cause prevention of light transmission and cause ulcers?

A

Allows fluid to enter the stroma

Corneal oedema disrupts lamellae

35
Q

Does the epithelium of the cornea heal well after damage? How?

A

Yes

By neighbouring cells, stem cells at limbus and mitosis

36
Q

What happens when the cornea is damaged?

A

Neovascularisation = blood vessels grow from limbus to aid healing

37
Q

When the cornea is damaged, neovascularisation occurs. It can be superficial or deep. Where do these new vessels come from?

A 
Superficial = from conjunctiva blood vessels
Deep = ciliary plexus
38
Q

What happens to blood vessels from neovascularisation after corneal damage has healed?

A

Vessels narrow
Leave ghost vessels
May cause pigmentation

Eye and CNS case discussion (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions