BS - Uvea - Week 2

Question 1

Where does the choroid begin?

Answer 1

Begins where the ciliary body ends.

Question 2

What is the function of ciliary bodies?

Answer 2

Production of aqueous humour for nutrition.

Question 3

What is the pars plicata?

Answer 3

It surrounds the ciliary processes, responsible for aqueous humour production.

Question 4

What do the pars plicata attach to?

Answer 4

To the lens via zonules.

Question 5

What is the pars plana, and what does it merge with? What is the border of mergence called?

Answer 5

Connects to the pars plicata inward, and merges with the retina. The border of pars plana and retina is called the ora serrata.

Question 6

What is the favoured site for surgical injection to the eye, and why?

Answer 6

Ora serrata, as its least likely to be injured.

Question 7

Describe the ciliary process epithelium.

Answer 7

It is double layered, in contact with the aqueous humour.

Question 8

Is the inner epithelium of the ciliary processes pigmented?

Answer 8

No, only the outer epithelium is.

Question 9

Where is the newly made aqueous humour released, and where does it go?

Answer 9

Released into the posterior chamber, and travels up, around the lens, and through the pupil, into the anterior chamber.

Question 10

What is the inner layer of the epithelium of ciliary processes continuous with?

Answer 10

Neural retina.

Question 11

What is the outer pigmented layer of the epithelium of ciliary processes continuous with?

Answer 11

RPE and iris.

Question 12

What surrounds the outer epithelium of the ciliary processes?

Answer 12

The inner non-pigmented layer.
Inner surrounds outer.
Inner is non-pigmented, outer is pigmented.

Question 13

What does the ciliary stroma border?

Answer 13

The ciliary muscle.

Question 14

What covers the ciliary stroma?

Answer 14

Ciliary epithelium layers

Question 15

Is the ciliary stroma vascular or avascular?

Answer 15

Richly vascularised.

Question 16

Are pigmented cells present in the ciliary stroma?

Answer 16

Yes, melanocytes.

Question 17

Are fibroblasts present in the ciliary stroma?

Answer 17

Yes.

Question 18

What immune cells can eb found in the ciliary stroma?

Answer 18

Mast cells, macrophages, and lymphocytes.

Question 19

Name the three ciliary muscles beginning with the most superficial. Which has the main bulk?

Answer 19

Longitudinal fibres - forms main bulk
Oblique fibres
Circular fibres

Question 20

Which of the ciliary muscles runs parallel with the sclera?

Answer 20

Longitudinal fibres

Question 21

During accommodation, which surface of the lens changes more, anterior or posterior?

Answer 21

Anterior.

Question 22

What happens to the lens with age?

Answer 22

Thickens

Question 23

What happens when you accommodate?

Answer 23

Ciliary muscles contract, which loosen the zonules, and allow the lens to increase in curvature.
When relaxed, zonules tighten, and pull the lens.

Question 24

Do ciliary muscles receive mainly sympathetic or parasympathetic innervation?

Answer 24

Parasympathetic system.

Sympathetic - 1-2%

Question 25

Describe the parasympathetic innervation to the ciliary muscles, including the receptor, nerve pathway, and cranial nerve if applicable.

Answer 25

``` Receptor - muscurinic receptors To - the midbrain Via - ciliary ganglion Nerve - short posterior ciliary nerve Cranial nerve III, inferior division ```

Question 26

Describe the sympathetic innervation to the ciliary muscles, including the receptor, nerve pathway, and cranial nerve if applicable.

Answer 26

``` Receptor - β2 adrenergic receptors To - the midbrain Via - superior cervical ganglion Nerve - long ciliary nerve Cranial nerve III, inferior division ```

Question 27

What vessels supply blood to the ciliary bodies?

Answer 27

Long posterior ciliary arteries | Anterior ciliary arteries

Question 28

How do anterior ciliary arteries reach the ciliary bodies? What about the long posterior ciliary arteries?

Answer 28

They travel via the extraoccular muscles | Long posterior ciliary arteries travel between the sclera and the choroid.

Question 29

What do the anterior ciliary arteries and long posterior ciliary arteries form?

Answer 29

Major arterial circle.

Question 30

Describe the choroid, its colour, and its four main layers.

Answer 30

``` Thin inner brown lining of the sclera Suprachoroid Stroma Choriocapillaris Bruch's membrane ```

Question 31

Where does the choroid cover?

Answer 31

From the optic nerve, to the ciliary bodies.

Question 32

What is another name for the suprachoroid, and what kind of tissue is it? What arteries and cells are found here?

Answer 32

Lamina fusca Is loose connective tissue Long and short posterior ciliary arteries move into this space Melanocytes are found here

Question 33

Describe the two layers of the choroid stroma. Arteries (P/A CA) run here, describe what happens to arterial diameters.

Answer 33

Haller's layer - outer layer, with larger diameter arteries | Sattler's layer - inner layer, middle/medium-sized arteriolar branches

Question 34

Describe the choriocapillaris. Where is its greatest density?

Answer 34

Large fenestrated capillary bed. Greatest density in the macular region.

Question 35

What layerchoroid layer is closest to the retina?

Answer 35

Choriocapillaris

Question 36

Where are vortex veins found, and how many does each eye have?

Answer 36

Found in the choriocapillaris, 4 per eye, one for each quadrant.

Question 37

Where can bruch's membrane be found?

Answer 37

Between the choroid and RPE.

Question 38

Describe the 5 layers of bruchs membrane.

Answer 38

``` RPE basement membrane Inner layer of collagen Meshwork of eastic fibres Outer layer of collagen Endothelial basement membrane ```

Question 39

Where does drusen develop, and what is it a precursor to?

Answer 39

Develops between the RPE basement membrane and the inner collagen layer. Precursor to AMD.

Question 40

How does Bruchs membrane appear with age?

Answer 40

Takes on a patchy appearance with age., and thickens.

Question 41

What happens to choroidal vessels with age?

Answer 41

Arteriosclerosis >60 years.

Question 42

What separates the anterior and posterior chambers of the eye?

Answer 42

Iris

Question 43

Where does the iris insert into?

Answer 43

Ciliary body - iris root

Question 44

What is the free edge of the iris called?

Answer 44

Pupillary margin

Question 45

What are the embryological origins of the iris?

Answer 45

Stroma - mesoderm | Muscles, epithelium - ectoderm

Question 46

Is the iris pigmented anteriorly or posteriorly?

Answer 46

Posteriorly.

Question 47

Describe crypts of Fuch, and their function.

Answer 47

Openings on the anterior surface of the iris, allowing deeper structures to be bathed in aqueous humour.

Question 48

What is the pupillary ruff?

Answer 48

Continuation of the posterior pigmented layer over the edge of the pupil anteriorly.

Question 49

What are collarettes?

Answer 49

Divides the pupil into zones.

Question 50

What are contraction furrows?

Answer 50

Ridges in the periphery that deepen as the pupil dilates.

Question 51

Describe the posterior surface of the iris surface. What structure is found close to the pupillary zone?

Answer 51

A series of radial contraction folds are found close to the pupillary zone called Schwalbes folds. To the periphery of this are the circular contraction folds.

Question 52

Does the anterior border of the iris have an epithelium?

Answer 52

No

Question 53

Is the stroma of the iris vascularised?

Answer 53

Yes

Question 54

Describe the pigmented epithelium of the iris.

Answer 54

Composed of 2 layers of cells, densely packed with melanin.

Question 55

Where are sphincter pupillae found, what kind of muscle is it, and what nerve innervates it?

Answer 55

Found in the pupillary zone, is a smooth muscle, and receives parasympathetic supply from SPCN CNIII.

Question 56

Define meiosis.

Answer 56

Pupillary constriction.

Question 57

Define mydriasis.

Answer 57

Pupillary dilation.

Question 58

Where are dilator pupillae found, what kind of muscle is it, and what nerve innervates it?

Answer 58

Found in the periphery of the iris, and gradually diminishes until the mid-portion od sphincter muscles. Innervated by sympathetic supply via LPCN.

Question 59

What does eye colour depend on?

Answer 59

Amount of melanin in the epithelium.

Question 60

What colour are infant eyes?

Answer 60

Born light, gradually darkens with melanin deposition.

Question 61

How is melanin found in the iris?

Answer 61

In bundles of melanosomes.

Question 62

What kind of receptors and neurotransmitters are used for iris innervation?

Answer 62

Acetylcholine neurotransmitter | Muscurinic or nicotinic receptors

Question 63

The nerve pathway for sympathetic innervation to the iris follows what?

Answer 63

The carotid plexus.

Question 64

Where does sensory innervation to the iris originate from? Name each nerve branch.

Answer 64

Ophthalmic branch of the trigeminal nerve. Continues as nasociliary nerve. Follows the long ciliary nerve.

Question 65

Consider dilating drops, what chemicals would be needed to target sympathetic/parasympathetic innervation? Mention if it increases or decreases activity.

Answer 65

Increased sympathetic activity - Sympathomimetic | Decreased parasympathetic activity - antimuscurinics

Question 66

Consider constricting drops. What chemicals would be needed to target sympathetic/parasympathetic innervation? Mention if it increases or decreases activity.

Answer 66

Increased parasympathetic activity - muscurinic agonists

Question 67

How many arterial circles are formed?

Answer 67

One major to the periphery, one minor closer to the centre.