Ciliary Body and Aqueous Production

Question 1

Where do the suspensory ligaments of the zonule attach to the ciliary body?

Answer 1

• Attach at the ora serrata and merge with the basement membrane of the unpigmented epithelium on the dentate processes
• When they reach the ciliary processes, they divide into bundles and run in the valleys between the ciliary processes

Question 2

Why do the crests of the ciliary processes appear white in a micrograph?

Answer 2

They are unpigmented

Question 3

What is the function of the inner epithelium of the ciliary body?

Answer 3

Its unpigmented and is where aqueous humour is produced

Question 4

What is the function of the outer epithelium?

Answer 4

Its pigmented and absorbs light - part of eyes ‘black box’ effect

Question 5

How is ciliary body innervated?

Answer 5

Parasympathetic
The ciliary body moves forward and inwards towards the lens and this releases tension off the lens which means the lens takes a more rounder shape and a signal is sent to the Edinger Westphal nucleus and preganglionic fibres within third nerve travel to the ciliary ganglion and synapse with post ganglionic fibres in the short ciliary nerve

Question 6

What type of drug would lead to a paralysis of the accommodative muscles (cycloplegia)?

Answer 6

Atropine - anti muscarinic - blocks muscarinic receptor, so acetylcholine cant bind and theres no contraction

Question 7

What is Ciliary muscle?

Answer 7

Smooth muscle, has 3 diff orientations within the ciliary body:

• longitudinal
• radial
• circular

Question 8

Why might accommodation to a near object increase aqueous inflow?

Answer 8

When you accommodate, the longitudinal fibres contract and this increases pore size in the trabecular meshwork which increases the aqueous humour outflow