Q.Name the three layers of the wall of the human eyeball, from outermost to innermost, and state one structure found in each.

[!TLDR] Outer layer = sclera + cornea (protection/light entry); middle layer = choroid + ciliary body + iris (nourishment/focus/pupil control); inner layer = retina (photoreceptors). [!ANSWER] Outer (fibrous): sclera, cornea. Middle (vascular/uvea): choroid, ciliary body, iris. Inner (nervous): retina.

The wall of the human eyeball is built of three concentric layers. The outer (fibrous) layer consists of the tough, white, protective sclera covering most of the eyeball, continuous anteriorly with the transparent cornea, through which light first enters. The middle (vascular) layer, or uvea, consists of the pigmented, vascular choroid (which nourishes the outer retina and absorbs stray light), continuing forward into the ciliary body (containing the ciliary muscles that adjust lens shape) and the pigmented, muscular iris (which controls pupil diameter). The inner (nervous) layer is the retina, which contains the light-sensitive photoreceptor cells (rods and cones) and converts the focused image into nerve impulses. [!ANSWER] Outer layer: sclera + cornea; middle layer: choroid + ciliary body + iris; inner layer: retina.

Work from outside to inside, naming the structures found in each of the three named layers.

Do not place the lens in one of the three wall layers — the lens is a separate internal structure, not part of the eyeball's wall.