Uvea 2
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Questions and Answers

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?

<p>Sphincter muscle (B)</p> Signup and view all the answers

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

<p>Zonule fibers (B)</p> Signup and view all the answers

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

<p>Blood supply to the ciliary body (C)</p> Signup and view all the answers

How does ciliary muscle contraction impact the lens during accommodation?

<p>It thickens and increases the curvature of the lens (D)</p> Signup and view all the answers

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

<p>Supports and nourishes the retina (D)</p> Signup and view all the answers

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

<p>Relaxation of circular muscle fibers (B)</p> Signup and view all the answers

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

<p>Fenestrated capillaries in ciliary processes (C)</p> Signup and view all the answers

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

<p>Ultrafiltration (B)</p> Signup and view all the answers

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

<p>To transport molecules across the membrane in an energy-utilizing process (D)</p> 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?

<p>Na/K ATPase (A)</p> Signup and view all the answers

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

<p>Ultrafiltration involves active transport, while diffusion is passive. (B)</p> 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?

<p>Ultrafiltration (B)</p> Signup and view all the answers

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

<p>80-90% (D)</p> Signup and view all the answers

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

<p>Diffusion and active secretion (C)</p> Signup and view all the answers

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

<p>'Na/K ATPase' (D)</p> 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?

<p>'It includes a hydrostatic pressure component' (D)</p> Signup and view all the answers

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

<p>Maintains pressure and shape of the eye (C)</p> Signup and view all the answers

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

<p>To prevent light scatter and ensure maximum light transmission (C)</p> Signup and view all the answers

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

<p>Proteins pass easily out of ciliary vessels fenestrations (B)</p> Signup and view all the answers

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

<p>AH production follows a circadian rhythm (B)</p> Signup and view all the answers

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

<p>Choroid (C)</p> Signup and view all the answers

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

<p>Loss of accommodation ability (A)</p> Signup and view all the answers

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

<p>Supply iris and ciliary body (D)</p> Signup and view all the answers

What causes pigmentation dispersion syndrome according to the text?

<p>Excessive membrane basement deposition (D)</p> Signup and view all the answers

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

<p>'Beam of light' phenomenon in the anterior chamber (C)</p> Signup and view all the answers

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

<p>Thin iris root tear away from ciliary body (D)</p> 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?

<p>Carbonic anhydrase (D)</p> Signup and view all the answers

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

<p>Moderating Cl- flux (D)</p> Signup and view all the answers

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

<p>Requiring ATP and enzymes like Na/K ATPase and carbonic anhydrase (A)</p> Signup and view all the answers

Which ion primarily drives secretion into the posterior chamber?

<p>Sodium (C)</p> Signup and view all the answers

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

<p>To catalyze important reactions involving CO2 and H2O (A)</p> Signup and view all the answers

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

<p>They decrease bicarbonate production (C)</p> Signup and view all the answers

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

<p>$HCO_3^-$ (C)</p> Signup and view all the answers

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