Overview
This lecture covered the anatomy of the eye, outlining the main structures, their functions, and how they contribute to vision.
External Structures of the Eye
- Extrinsic eye muscles on the outside of the eyeball control its movement.
- The white part of the eye is called the sclera.
- The clear, dome-shaped front part is the cornea.
Layers and Chambers of the Eye
- Under the sclera is the choroid layer, which provides nutrients.
- The colored part of the eye is the iris.
- The pupil is the central opening in the iris, allowing light to enter.
- The space between the cornea and lens is the anterior chamber, filled with aqueous humor (watery fluid).
- The space behind the lens is the posterior chamber, filled with vitreous humor (gelatinous substance).
Internal Structures and Functions
- The retina is the innermost layer, containing photoreceptors (rods and cones).
- The lens focuses light and separates anterior and posterior chambers.
- The optic disc (blind spot) is where nerves and blood vessels exit; no photoreceptors are present.
- The fovea centralis, next to the optic disc, is rich in cone cells and provides sharpest color vision.
- The optic nerve transmits visual information to the brain.
Supporting Structures
- The ciliary body is a muscle that changes lens shape via suspensory ligaments, allowing focus adjustment.
- Blood vessels (arteries and veins) run along the retina, supplying nutrients.
Key Terms & Definitions
- Sclera — White, protective outer layer of the eye.
- Cornea — Clear, dome-shaped surface covering the front of the eye.
- Choroid — Middle, vascular layer supplying nutrients.
- Iris — Colored muscle controlling pupil size.
- Pupil — Opening in the iris for light entry.
- Lens — Structure that focuses light onto the retina.
- Aqueous Humor — Watery fluid in anterior chamber.
- Vitreous Humor — Gel-like substance in posterior chamber.
- Retina — Light-sensitive layer with rods and cones.
- Optic Disc — Area where optic nerve exits; no vision (blind spot).
- Fovea Centralis — Region with highest cone density, providing sharp color vision.
- Ciliary Body — Muscle that alters lens shape for focusing.
Action Items / Next Steps
- Review the anatomy and functions of each eye structure.
- Be able to identify the sclera, cornea, iris, pupil, lens, retina, and optic nerve on diagrams or models.