Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Year 2 Semester 2 > Eye > Flashcards

Eye Flashcards

(63 cards)

Start Studying
0
Q

In the dog, which vessels pass through foramina to gain access to the orbit?

A

Ophthalmic artery and vein
Orbital vein
Cranial nerves 2, 3, 4, 6 (optic, oculomotor, trochlear, abducens)
Ophthalmic branch of cranial nerve 5

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

In the horse, a portion of the orbit is contributed to by the zygomatic process of which bone?

A

Temporal

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

What are the three layers of the orbital fascia?

A

Outer=periorbita
Fascia bulbi
Fascial sheaths of the extra-ocular muscles

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

Which species do not possess a retractor bulbi muscle?

A

Birds and snakes

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

What are the functions of the eyelids?

A

Close to exclude light
Protect the eyeball
Spread the tear film across the eye and into the lacrimal punctae
Help to remove foreign material from the eye

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

At what age do cats and dogs open their eyes?

What is the eyelid opening called?

A

10-14 days

Palpebral fissure

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

The cilia on the upper eyelid (eyelashes) are associated with which glands?

A 
Modified sweat glands (glands of Moll)
Sebaceous glands (glands of Zeis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What causes a stye to form?

A

Infection of sebaceous or sweat glands in the upper eye lid

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

In the dog, the lateral palpebral ligament is absent, but what is its function replaced by?

A

Retractor anguli oculi muscle

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

Closure of the eyelids is due to what?

A

Contraction of the orbicularis oculi muscle, which is innervated by the facial nerve (CN VII)

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

Sensory innervation to the eyelids is via which nerve?

This branches into what?

A

Trigeminal (CN V)
Branches into ophthalmic branch (innervates most of upper lid and medial part of lower lid) and maxillary branch (innervates lower lid and joins with ophthalmic branch to supply lateral portion of upper lid)

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

What is the nictitating membrane?

Where does it sit?

A

Third eyelid
A reflection of conjunctiva containing a T-shaped cartilage support.
Sits ventromedially in the conjunctival sac, and the free edge is snug against the eyeball

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

What are the three portions of the tear film?

A

Lipid layer
Mucin layer
Aqueous layer

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

The lacrimal nerve is a branch of which nerve?

A

Ophthalmic branch of CNV

Provides parasympathetic and sympathetic innervation

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

What are the three layers of the globe and what do they do?

A

Fibrous layer- supports the eyeball shape
Uvea- provides nutrition to the structures of the eye and acts to alter light transmission
Neural layer- retina

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

What is the cornea?

How thick is it in dogs and cats?

A

The clear, curved rostral surface of the eyeball which transmits and refracts light.
0.7mm thick

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

Which 2 factors give the cornea its clarity?

A

Lack of corneal blood vessels

Arrangement of lamellae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What makes up the anterior and posterior uvea?

A

Anterior uvea= iris and ciliary body

Posterior uvea= choroid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe the pathway of aqueous humour

A

It is produced in the posterior chamber, flows through the pupil into the anterior chamber and drains at the iridocorneal angle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the 4 layers of the choroid?

A

Suprachoroidea-transition between sclera and choroid
Large vessel layer-cools the eye
Medium vessel layer-contains tapetum lucidum
Choriocapillaris-consists of fenestrated capillaries which supply the retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is aqueous humour produced by?

A

Ciliary processes of the ciliary body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the normal range for intra-ocular pressure in a dog?

A

15-25mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is a glaucoma formed?

A

When production of aqueous humour exceeds drainage and intra-ocular pressure rises

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are ‘floaters’?

A

Clumps of hyaluronic acid, occurs in old age when the lamellar arrangement of fibrils in the vitreous humour breaks down and the vitreous becomes more liquid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
How does a cataract form?
Changes inside the lens disrupt normal metabolism and lead to deposition of lens protein or accumulation of vacuoles and disruption of lens fibres. This affects transparency and size of lens.
25
What are the 3 inner layers of the retina?
Nerve fibre layer Ganglion cell layer Inner plexiform layer
26
Where are cones most numerous?
Area centralis of the retina
27
Which area of the retina has the most ganglion cells?
Visual streak
28
Give 3 functions of the retinal pigment epithelium
Phagocytoses spent photoreceptor segments Vitamin A metabolism Moves metabolites into and out of the retina
29
How are cats able to actively protrude their third eyelids?
They possess some striated muscle in their third eyelids
30
What does each layer of the tear film do? | Lipid layer, mucin layer, aqueous layer
Lipid layer: produced from meibomian glands; reduces evaporation and creates a barrier at the lid margin Mucin layer: produced by conjunctival goblet cells; stabilises the tear film Aqueous layer: produced by lacrimal glands and 3rd eyelid gland; provides lubrication, protection and nutrition to the epithelium it covers
31
What suspends the lens?
Zonular fibres
32
Where is the main site of drainage of aqueous humour?
Iridocorneal angle
33
What are the 4 major layers of the choroid?
Suprachoroidea-transition between sclera and choroid, elastic, pigmented Large vessel layer-contains vascular plexus, cools the eye Medium vessel layer-contains vessels and tapetum lucidum Choriocapillaris-consists of fenestrated capillaries which supply the retina
34
Aqueous humour is produced by which 3 processes?
``` Diffusion (of solutes down conc. gradient into the aqueous) Ultrafiltration (due to differences in hydrostatic pressure in ciliary body capillaries, and intra-ocular pressure) Active secretion (of Na, which brings water across too) ```
35
What is the function of the lens?
To focus light on the retina
36
Which structures are visible in the fundus?
Optic disc, retina, retinal pigment epithelium (RPE), choroid and sometimes the sclera
37
Where is the tapetum lucidum located?
Medium vessel layer of the choroid
38
In which ways can drugs be administered to penetrate the globe?
Topically Crossing the cornea, conjunctiva or sclera Systemically by crossing the blood:ocular barrier
39
After topical administration of an ocular drug, what are the 3 ways it can be distributed?
Drained by lacrimal drainage system Penetrates into the eye via cornea/sclera Enters systemic circulation through conjunctival and nasal vessels
40
How much of a topically-applied drug actually reaches the anterior chamber?
Between 1 and 10%
41
How can intra ocular bioavailability of a drug be improved?
Increasing retention of the drug in the Palpebral fissure | By increasing its ability to penetrate the cornea
42
What are the layers of the cornea that a drug has to penetrate?
Epithelium (tight junctions) (can get through epithelium by moving between cells (paracellular, water-soluble) or moving through cells (transcellular, lipid-soluble)) Bowman's layer Stroma (facilities diffusion of water-soluble drugs but not lipid-soluble) Descemet's membrane Endothelium (gap junctions, both lipid and water-soluble drugs can pass through)
43
After a drug has penetrated the cornea, where does it go?
Aqueous humour -> iris -> ciliary body
44
Is the ionised form of a drug water or lipid soluble?
Ionised form= water-soluble | Nonionised form= lipid-soluble
45
What does the blood:ocular barrier consist of?
BAB (blood:aqueous barrier) and BRB (blood:retinal barrier)
46
Why would we want to dilate the pupil?
To facilitate better fundic examination
47
How do we dilate the pupil?
Use either: Sympathomimetic to contract the dilator muscle Parasympatholytic to relax the Iris sphincter muscle eg Atropine
48
What kind of stimulation causes pupils to constrict and dilate?
Sympathetic -> pupils dilate | Parasympathetic -> pupils constrict
49
How can you investigate Horner's syndrome?
Dogs with Horner's syndrome present with constricted pupils. | Give a sympathomimetic dug (α1-selective adrenergic drug eg phenylephrine) to dilate the pupils.
50
Which drug can you use as a tear substitute?
Pilocarpine, increases tear production, parasympathomimetic
51
How do we treat glaucoma?
By increasing outflow of aqueous humour, reducing production or both
52
What types of drugs can we use to treat glaucoma?
``` Osmotic diuretics (draws water out of aqueous) Carbonic anhydrase inhibitors (produce bicarbonate ions which draw water out of the aqueous, eg Brinzolamide) Beta blockers (reduce aqueous formation, b1 antagonists eg betaxolol) Parasympathomimetics (constrict the pupil which widens the drainage angle and so increases aqueous outflow eg pilocarpine) ```
53
What is the function of: Atropine Pilocarpine
Atropine: dilates pupil Pilocarpine: constricts pupil
54
What are the functions of rods and cones?
Rods-sensitive to low light levels but not colour. Black and white night vision. Cones-sensitive to bright light/day vision. Provide colour vision.
55
Where does the optic nerve leave the eyeball?
Slightly ventral to the posterior pole
56
The axons of which cells form the optic nerve?
Ganglion cells
57
Which layer of the retina is supported by the choroid?
Nervous layer (receptor cells, rods and cones)
58
What is the retinal pigment epithelium attached to?
Choroid
59
Which layers of the eye contribute to the iris?
Choroid, retina, cornea
60
What fills the anterior and posterior chambers?
Aqueous humour
61
What prevents backflow of aqueous humour from the anterior to posterior chamber?
The valve-like action of the iris
62
Why does a corneal ulcer take a long time to heal?
Superficial ulcers heal rapidly because the outermost layer of the cornea is an epithelium (epithelial cells have a huge capacity for regeneration). However, a deep ulcer heals slowly because the collagen fibres in the main body of the cornea don't have their own blood supply (important for delivering WBCs to produce scar tissue). Sometimes a conjunctival flap is required to provide a blood supply

Year 2 Semester 2 (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions