Physiology: Aqueous humour Production and Circulation Flashcards
describe what aqueous humour is
a specialised fluid that bathes the structures within the eye
what are the functions of the aqueous humour
provides oxygen and metabolites, contains bicarbonate which buffers H+ produced in the cornea and lens by anaerobic glycolysis
where is aqueous humour produced
by energy dependant process in epithelial layer of the ciliary body into the posterior chamber of the eye
where does aqueous humour flow to after being produced
into the anterior chamber of the eye
describe the drainage of aqueous humour
drains to scleral venous sinus through a trabecular meshwork and the canal of Schlemm
describe the organisation of the epithelium of the ciliary body and posterior surface of the iris
2 juxtaposed layers of epithelial cells;
a forward continuation of the pigment epithelium of the retina(PE) overlain by an inner non-pigmental epithelium(NPE) layer
describe the movement of ions from the NPE to aqueous humour and what accompanies it
Na and Cl go from interstitial fluid to aqueous humour in exchange for HCO3 and H+ the other way, via Na/K/Cl transporter
accompanied by water via aquaporins and osmosis from NPE
describe the role of carbonic anhydrase
catalyses hydration of CO2, forms HCO3 and H+ and allows exchange for Na and Cl which enter aqueous humour
how is intraocular pressure maintained and what is it maintained at
maintained by balance between secretion and drainage of aqueous solution, maintained at 17mmHg above atmospheric
how does aqueous humour relate to the set of diseases called glaucoma
glaucoma caused by raised intraocular pressure, due to imbalance between rates of secretion and removal of aqueous humour
what drugs will reduce aqueous humour production, and give an example
carbonic anhydrase inhibitors
example = Dorzolamide
