1.2.1, Figure 1.8: Parts of the human eye and their functions

Sclera (Main Wall Layers)

Strong layer that maintains the shape of the eye and protects it.

Choroid (Main Wall Layers)

Black layer that prevents reflection of light in the eye.

Retina (Main Wall Layers)

Layer containing photoreceptors which detects light and produces nerve impulses.

Conjunctiva (Protective Layers)

Transparent membrane which protects the front part of the sclera.

Cornea (Light Entry)

Transparent layer which refracts and focuses light into the retina.

Iris (Light Entry)

The colored part of the eye which controls the size of the pupil.

Pupil (Light Entry)

Opening in the center of the Iris which controls the quantity of light entering the eye.

Eye lens (Focusing)

Transparent and elastic convex lens which focuses light onto the retina.

Ciliary muscle (Focusing)

Muscle that changes the thickness of the eye lens through contractions and relaxations.

Suspensory ligaments (Focusing)

Strong fibers which hold the eye lens in position.

Aqueous humour (Fluids)

Transparent liquids which maintains the shape of the eyeball and focuses light into the eye.

Vitreous humour (Fluids)

Transparent jelly like substance which maintains the shape of the eyeball and focuses light onto the retina.

Yellow spot (Parts of retina)

Part of the retina which is most sensitive to light as it has many photoreceptors.

Blind spot (Parts of the retina)

Path of the retina which is not sensitive to light as there are no photoreceptors and an exit point for all optic nerve cells.

Optic nerve (Signal transmission)

Nerve fibers which carry nerve impulses from the retina to the brain to be interpreted.