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Anatomy and Function of the Eye

Sep 18, 2024

Structure of the Eye

1. Sclera

  • Description: White part of the eye, thick fibrous tissue.
  • Function: Protects the eye and serves as an attachment point for muscles.

2. Cornea

  • Description: Transparent front part of the eye.
  • Function: Protects the eye and bends light slightly.
  • Protection: Covered by a thin layer of epithelial cells called the conjunctiva.
    • Conjunctiva: Protects from friction, moisturizes, and shields from dust/debris.

3. Anterior Chamber & Aqueous Humor

  • Aqueous Humor: Fluid (water and salt) filling the anterior chamber.
  • Role: Provides nutrients and maintains intraocular pressure.

4. Lens

  • Description: Bi-convex, curved on both sides.
  • Function: Further bends light; changes shape for focus (near/far vision).
  • Adjustment: Controlled by the ciliary body:
    • Suspensory Ligaments: Connect lens to ciliary muscles.
    • Ciliary Muscles: Adjust lens thickness.

5. Iris and Pupil

  • Iris: Colored part of the eye, controls the size of the pupil.
  • Pupil: Hole that regulates light entry.
    • Darkness: Iris expands, pupil enlarges.
    • Brightness: Iris contracts, pupil shrinks.

6. Posterior Chamber & Vitreous Humor

  • Vitreous Humor: Jelly-like substance in the posterior chamber.
  • Function: Maintains eye shape and holds the lens in place.

7. Retina

  • Function: Converts light rays into neural impulses.
  • Feature: Reddish tint (causes red-eye effect in photos).
  • Structure: Contains photoreceptors (rods and cones).
  • Optic Nerve: Transmits visual information to the brain.

8. Choroid

  • Description: Network of blood vessels, black pigmented.
  • Function: Nourishes retinal and other eye cells.
  • Animal Variation: In cats, it's shiny to enhance night vision.

9. Macula and Fovea

  • Macula: Region of the eye containing the fovea.
  • Fovea: Center of the macula, rich in cones, allows detailed vision.

Summary

Understanding the structural intricacies of the eye reveals how each component contributes to the overall functionality of vision, from light entry and refraction to image conversion and transmission to the brain.

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