Uvea 2

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What are the four layers of the iris, as described in the text?

Superficial layer, Smooth muscle layer, Squamous epithelium layer, Basal layer

Anterior border layer, Stroma and sphincter muscle, Anterior epithelium and dilator muscle, Posterior epithelium (correct)

Anterior border layer, Stroma and smooth muscle, Anterior epithelium and circular muscle, Posterior epithelium

External layer, Circular muscle layer, Dilator muscle layer, Internal layer

Which structure in the eye acts as a diaphragm to regulate the amount of light entering?

Cornea

Retina

Iris (correct)

Lens

What is the primary function of the ciliary body?

Control of eye movements

Production and secretion of tears

Regulation of intraocular pressure

Production and secretion of aqueous humor (correct)

What muscle in the eye is responsible for pupil constriction?

Sphincter muscle Signup and view all the answers

Which fibers are responsible for attaching the ciliary muscles to the trabecular meshwork in the eye?

Zonule fibers Signup and view all the answers

What is the role of Haller's layer within the choroid?

Blood supply to the ciliary body Signup and view all the answers

How does ciliary muscle contraction impact the lens during accommodation?

It thickens and increases the curvature of the lens Signup and view all the answers

What is one of the functions of Bruch's membrane in the eye?

Supports and nourishes the retina Signup and view all the answers

What causes a reduction in diameter of the ring formed by the ciliary body?

Relaxation of circular muscle fibers Signup and view all the answers

What is a significant factor in aqueous humor production according to the text?

Fenestrated capillaries in ciliary processes Signup and view all the answers

Which process involves the passive flow of blood plasma from the capillaries into the ciliary stroma?

Ultrafiltration Signup and view all the answers

In the context of aqueous humor production, what is the main function of active secretion?

To transport molecules across the membrane in an energy-utilizing process Signup and view all the answers

Which enzyme in the nonpigmented ciliary epithelium is responsible for pumping Na+ using ATP in the process of aqueous humor production?

Na/K ATPase Signup and view all the answers

How does ultrafiltration differ from diffusion in terms of movement across a membrane?

Ultrafiltration involves active transport, while diffusion is passive. Signup and view all the answers

Which process is similar to dialysis but involves a hydrostatic pressure to increase the rate of movement across a membrane?

Ultrafiltration Signup and view all the answers

What percentage of aqueous humor production is attributed to active secretion?

80-90% Signup and view all the answers

Which type of movements must substances undergo to become aqueous humor?

Diffusion and active secretion Signup and view all the answers

'Nonpigmented ciliary epithelium has two enzymes that catalyze reactions essential for aqueous formation' - What are these enzymes called?

'Na/K ATPase' Signup and view all the answers

'Ultrafiltration.This process is similar to dialysis, but with the addition of a hydrostatic pressure that increases the rate of net movement of water and salt molecules across the semipermeable membrane.' - What is unique about ultrafiltration compared to dialysis?

'It includes a hydrostatic pressure component' Signup and view all the answers

What is the primary function of the ciliary body aqueous humor?

Maintains pressure and shape of the eye Signup and view all the answers

Why does the aqueous humor have 200 times less protein than plasma?

To prevent light scatter and ensure maximum light transmission Signup and view all the answers

What is a consequence of the tight barrier formed by the NPE in the ciliary body?

Proteins pass easily out of ciliary vessels fenestrations Signup and view all the answers

Why does the AH production decrease by 50% during the night according to the text?

AH production follows a circadian rhythm Signup and view all the answers

Which structure provides nutrients to the outer retina according to the text?

Choroid Signup and view all the answers

What is a common age-related change in the ciliary body, as mentioned in the text?

Loss of accommodation ability Signup and view all the answers

What is the primary function of the long posterior ciliary arteries according to the text?

Supply iris and ciliary body Signup and view all the answers

What causes pigmentation dispersion syndrome according to the text?

Excessive membrane basement deposition Signup and view all the answers

What is a clinical application of Thyndall phenomenon as described in the text?

'Beam of light' phenomenon in the anterior chamber Signup and view all the answers

What characterizes persistent pupillary membrane remnants (PPM) according to the text?

Thin iris root tear away from ciliary body Signup and view all the answers

What is the main enzyme responsible for catalyzing the reaction involving CO2 and H2O in the movement of Na+ into the posterior chamber?

Carbonic anhydrase Signup and view all the answers

What is the indirect role of bicarbonate ions in the secretion into the posterior chamber?

Moderating Cl- flux Signup and view all the answers

How is active secretion for aqueous humor production in the ciliary body achieved?

Requiring ATP and enzymes like Na/K ATPase and carbonic anhydrase Signup and view all the answers

Which ion primarily drives secretion into the posterior chamber?

Sodium Signup and view all the answers

What is the proposed role of carbonic anhydrase in ion transport across the ciliary epithelium?

To catalyze important reactions involving CO2 and H2O Signup and view all the answers

Why do carbonic anhydrase inhibitors used in glaucoma therapy decrease aqueous secretion?

They decrease bicarbonate production Signup and view all the answers

Which ion has an indirect role in aqueous production by moderating Cl- flux?

$HCO_3^-$ Signup and view all the answers