Uvea choroid and ciliary body

Question 1

What is the function of ciliary body

Answer 1

Mexhansim of accommodation

Maintenance of lens zonules

Source of aqueous humour

Question 2

What is teh general arragnment of the ciliary body

Answer 2

Annular structure that extends anteriorly from scleral spur (anterior border) to ora serrata (posterior border that transits to choroid)

Question 3

What are the two parts the ciliary body can be divided into

Answer 3

Pars plicata (front)
Pars plana (back)

Question 4

What structure does the pars plicata contain

Answer 4

Ciliary processes

Question 5

Where does zonular fibres attach to the lens capsulefrom

Answer 5

Zonular fibres arise from pars plana, pass in between the processes and attach to the lens capsule

Question 6

What is the transition between the ciliary body and retina and how does it take place

Answer 6

Smoother posterior surface at the pars plana merges with the retina at ora setrata

Question 7

What is the viterous base

Answer 7

Where the viterous attaches to the posterior pars plana

Question 8

What are the three layers of the ciliary body from sclera to ciliary body

Answer 8

Supracililaris
Stroma
Epithelium

Question 9

What happens at the supraciliaris

Answer 9

Zone of transition from the ciliary stroma to the stroma

Question 10

What structure does the supraciliaris consist of

Answer 10

Collagen, fibroblasts and melanocytes

Question 11

What are the structures in the stroma (ciliary muscle)

Answer 11

Ciliary muscle, consits of 3 type of smooth muscle: lontiduinal, radial and circular fibres

Question 12

Description of epithelium (ciliary muscle)

Answer 12

double layer that extends from iris root to the retina

Question 13

What are the two layers of the epithelium (ciliary muscle)

Answer 13

Pigmented layer

Non-pigmented layer
(closer to sclera)

Question 14

What structures is the pigmented layer in continuation with

Answer 14

Anteriorly continous with the iris epithelium

Posteriorly continous with the anterior continuation of the retinal pigment epithelium

Question 15

What structures is the non pigmented layer in continuation with

Answer 15

Inner layer of cells that is continous with the nerouvs part of the retina

Question 16

What role does the non-pigmneted layer (IMPT)

Answer 16

Aqeuous production, where is modifies metabolites, they then diffuse from the capillaries of the ciliary processes and secret the product as aqueous humour into the poseterior chamber

Question 17

What is the function of the blood aqeuous barrier

Answer 17

seperates the interior portion of the eye from blood entering the eye for maintenenace of transparency

Question 18

What is the blood aqeuous barrier formed by

Answer 18

non fenestrated iris vessels

Question 19

What could eye inflammation, intraocular surgery or trauma result in for the blood aqueous barrier

Answer 19

damage to the barrier. which results in the leakage of plasma proteins into anterior and posterior chambers, affecting transparency

Question 20

What is the blood supply to the ciliary muscle

Answer 20

It contains the major arterial circle (near its attachment to the root of the iris) :
- 2 long posterior and 4-6 anterior ciliary ateries

The extensive capiliary bed in ciliary processes and vessels of ciliary muscles

Question 21

What is the venous drainage in the ciliary body

Answer 21

Vortex veins

Question 22

What is the nerve supply to ciliary muscles

Answer 22

Postganglionic parasympathetic fibres, via short ciliary nerves

Sympathetic fibres for vasoconstriction distrbuted to muscle and blood vessels

Question 23

Where does the choroid attend from and to

Answer 23

Anteriorly from ora serrata to edge of optic disc

Question 24

Description of choroid

Answer 24

A vascular pigmented layer between sclera and retina

Question 25

What are the four layer of the choroid

Answer 25

Suprachoroid Stroma Choriocapillaris Bruch's membrane (furthest from retina to closest)

Question 26

State the function of the choroid

Answer 26

Suprachoroidal space provides a route for blood vessels to the anterior uvea High blood flow thorugh choroidal vessels regulate eye temperature Supplies metabolites and removes waste products from the outer layers of the retina Choroidal pigments absorb light that passed thr retina to prevent internal reflection Bruch's membrane provides basement membrane for retinal pigment epithelium

Question 27

What arteries and nerves does the suprachoroidal space contain

Answer 27

long posterior ciliary arteries and nerves

Question 28

What does suprachoroidal space consist of

Answer 28

collagen fibres that are continous from sclera, melanocytes and fibroblast

Question 29

What does the stroma (choroid) consist of

Answer 29

Pigmented layer consists of loose connective tissue and b.v, containing melanocytes, fibroblasts, collagen, macrophages and lymphocytes

Question 30

What are the two layers that the blood vessels in the stroma of the choroid are divided into

Answer 30

Haller's layer, external layer of large diameter blood vessles Sattler's layer, internal layer of smaller diamete blood vessels (SS)

Question 31

Give a description of choriocapillaris

Answer 31

Single layer of fenestrated capillaires, fed by arteries in the stroma and drained by veins also in the stroma

Question 32

What are does the choriocapillaries consist of

Answer 32

Between the capillaries there are fine collagen fibres, fibroblasts and unmyelinated nerve fibers

Question 33

What are the five layers of the Bruch's membrane

Answer 33

Basement layer of the choriocapillaris Outer collagenous zone Elastic layer Inner collagenous zone Basement membrane of retinal pigment epitherlial cells

Question 34

What is the blood supply of the choroid

Answer 34

Circle of Haller-Zinn, formed by anastomosis of short posterior ciliary artery and via recurrent arteries from the major arteiral circle (are branches of ophthalmic artery)

Question 35

What is the blood drainage of the choroid

Answer 35

vorticose/ vortex vein, that drains int o superior and inferior opthalmic vein

Question 36

What is the nerve supply of the choroid

Answer 36

Short posterior ciliary nerve (carries parasympathetic and sympathetic nerves) Sympathetic nerve causes marked vasoconstriction which reduces choroidal blood flow