uvea ciliary body

Question 1

function of ciliary body

Answer 1

• Mechanism of accommodation
• Maintenance of lens zonules
• Source of aqueous humour

Question 2

ciliary body layers

Answer 2

• Supraciliaris
• Stroma
• Epithelium

Question 3

general arrangement of ciliary body

Answer 3

An annular structure that extends anteriorly from the scleral spur to ora serrata

• Scleral spur: attaches to anterior border of ciliary body, 1.5 mm from limbus
• Ora serrata: posterior border of ciliary body and then transit to the choroid

Question 4

superciliaris

Answer 4

• Zone of transition from the ciliary stroma to the sclera

- Consists of strands of collagen, fibroblasts and melanocytes

Question 5

ciliary body stroma

Answer 5

• Consists of loose connective tissue, rich in blood vessels & melanocytes
• Bulk of the stroma is filled with ciliary muscle
• The muscle is anchored at the scleral spur anteriorly, fibres dispense posteriorly into the stroma of the choroid
• Ciliary muscle
  > Consists of 3 types of smooth muscles fibres : longitudinal, radial & circular fibres

Question 6

ciliary body epithelium

Answer 6

• Double layer that extends from iris root to the retina
• Consists of
  > Pigmented layer
  > Non-pigmented layer

Question 7

pigmented layer of ciliary body epithelium

Answer 7

• Anteriorly continuous with the iris
  epithelium
• Posteriorly continuous with the anterior continuation of the retinal pigment epithelium

Question 8

non-pigmented layer of ciliary body epithelium

Answer 8

• Has a role in aqueous production where it modifies metabolites where they then diffuse from the capillaries of the ciliary processes and secrete the product as aqueous humour into posterior chamber
• Inner layer of cells that is continuous with the nervous part of the retina

Question 9

function of blood-aqueous barrier

Answer 9

separates the interior portion of the eye from blood entering the eye (maintenance of transparency)

Question 10

what is blood-aqueous barrier formed by?

Answer 10

• Tight junctions (zonula-occludens) of non-pigmented ciliary epithelium, and
• Non-fenestrated iris vessels

Question 11

damage to blood-aqueous barrier

Answer 11

• May occur due to eye inflammation, intraocular surgery or trauma
• Results in leakage of plasma proteins into the anterior and posterior chambers, affecting transparency

Question 12

ciliary body blood supply

Answer 12

• contains the major arterial circle near its attachment to the root of the iris formed by the anastomosis of the
  > 2 long posterior ciliary arteries
  > 4-6 anterior ciliary arteries
• An extensive capillary bed in the ciliary processes and the vessels of the ciliary muscles.
• Venous drainage is via the vortex veins, lesser extent via the anterior ciliary veins.

Question 13

ciliary nerve supply

Answer 13

• Ciliary muscle is innervated by the postganglionic parasympathetic fibres. The nerve fibres reach the muscle via the short ciliary nerves.
• Sympathetic fibres are distributed to the muscles and blood vessels (vasoconstriction) of the ciliary body.