Physiology of aqueous humour Flashcards
What is the role of aqueous humour?
bathes structures within the eye
provides oxygen, metabolites and contains bicarbonate
How does bicarbonate buffer the H production in the cornea?
aerobic glycolysis
What produces aqueous humour?
(epithelial layer of the) ciliary body in the posterior chamber
Where does the aqueous humour drain into?
scleral venous sinus
How does the aqueous humour drain into the scleral venous sinus?
trabecular meshwork and the canal of Schlemm
What covers the ciliary body epithelium and posterior surface of the iris?
pigmented epithelium of the retina - basolateral layer
non pigmented epithelium of the retina - apical surface
What is the basic composition of aqueous humour?
HCO3 and H
Where are HCO3 and H formed?
epithelial cells
How are HCO3 and H formed?
hydration of CO2
catalysed by carbonic acid
How are HCO3 and H transported into interstitial fluid?
across basolateal membranes of pigmented epithelium cells, in exchange for Na and Cl
How do Na and Cl enter/exit the epithelial cells?
enter - gap junctions between the PE and NPE cells
exite - Na/K/Cl cotransporter
How can the Na/Cl, HCO3/H exchange be inhibited?
carbonic anhydrase inhibitors - blocks production of HCO3 so this reaction doesnt happen
What is Na/Cl movement accompanied by?
water movement through aquaporins of non pigmented epithelial cells (ciliary epithelial cells)
Name some carbonic anhydrase inibitors?
Dorzolamide - eye drops
Acetazolomide - oral administration (systemic effects)
What is the volume of the posterior chamber?
60ml
