Flashcards Set

Three Tunics (Layers) of the Eye

1. Fibrous Tunic (outermost)

   • Sclera: White part of the eye; provides protection & muscle attachment.

   • Cornea: Transparent, bulging part at the front; refracts light.

2. Vascular Tunic (middle)

   • Choroid: Contains blood vessels.

   • Iris: Colored part; contains smooth muscle that controls pupil diameter.

   • Ciliary body & processes: Controls lens shape via suspensory ligaments for focusing (accommodation).

3. Neural Tunic (Retina)

   • Retina: Contains photoreceptors.

     • Rods: Black & white vision (low light).

     • Cones: Color vision.

   • Fovea centralis (inside the macula lutea): Sharpest vision.

   • Optic disc (blind spot): No photoreceptors; where the optic nerve exits.

Chambers & Fluids

• Anterior cavity (front of lens):

  • Aqueous humor (watery fluid) → constantly replaced.

  • Anterior chamber (between cornea & iris).

  • Posterior chamber (between iris & lens).

• Posterior cavity (behind lens):

  • Vitreous humor (gel-like; maintains eye shape, keeps retina in place, not replaced).

• Canal of Schlemm: Drains aqueous humor; blockage → glaucoma.