Episclera/Sclera/Ant. Uvea

Question 1

Question

What is the primary pathway in which aqueous humor exits the eye?

Trabecular outflow pathway
Ciliary processes
Vortex veins
Uveoscleral outflow pathway

Answer 1

Trabecular outflow pathway

Explanation
Aqueous humor exits the eye via two distinct pathways: the trabecular outflow pathway and uveoscleral pathway. Most aqueous humor exits through the trabecular outflow pathway. This involves passing through the three layers of the trabecular meshwork (uveal layer, corneoscleral layer, and juxtacanalicular layer) before entering Schlemm’s canal. It then passes into distal collector channels to aqueous veins that drain into the episcleral venous system. This pathway is often also referred to as the conventional outflow pathway as it handles most aqueous humor outflow.

Question 2

Question

Which structure of the eye is responsible for producing the aqueous humor?

Limbus
Choroid
Ciliary body
Iris

Answer 2

Ciliary body

Explanation
The ciliary body is responsible for producing the aqueous humor; more specifically, it is only the pars plana region of the ciliary body that actually secretes aqueous humor.

Question 3

Question

Which of the following regions of the trabecular meshwork pathway represents the site of greatest resistance to aqueous humor outflow?

Juxtacanalicular layer
Schlemm's canal
Episcleral veins
Uveal layer
Corneoscleral layer

Answer 3

Juxtacanalicular layer

Explanation
The majority of aqueous humor leaves the eye through the trabecular outflow pathway. This involves passing through the three layers of the trabecular meshwork: the uveal layer, the corneoscleral layer, and juxtacanalicular layer. Aqueous then enters Schlemm’s canal, where it moves into distal collector channels to aqueous veins that drain into the episcleral venous system.
Of these areas, the juxtacanalicular trabecular meshwork represents the site of the greatest resistance to aqueous humor outflow.