Q.Draw a neat labelled diagram of L.S. of the human eye.

A labelled L.S. of the human eye shows three coats (sclera/cornea, choroid/ciliary body/iris, retina), the lens, its two fluid-filled chambers, and the optic nerve exit point — described here in place of a drawn figure.

Since this format cannot render an actual drawing, the required labelled structure is described part by part, in the order it would be drawn and labelled in a longitudinal (L.S.) diagram of the eyeball:

Outer (fibrous) coat:

• Sclera — the tough, opaque white outer layer covering most of the eyeball, giving it shape and protection.
• Cornea — the transparent, curved front continuation of the sclera, through which light first enters and is partly focused.

Middle (vascular) coat:

• Choroid — a dark, pigmented, richly vascular layer that nourishes the eye and absorbs stray light.
• Ciliary body — a thickened anterior extension of the choroid, holding the lens in place via suspensory ligaments and controlling its shape (accommodation).
• Iris — the pigmented, muscular diaphragm in front of the lens, with a central opening.
• Pupil — the opening in the centre of the iris that regulates the amount of light entering the eye.

Lens:

• A transparent, biconvex structure held behind the iris by suspensory ligaments from the ciliary body, focusing light onto the retina.

Chambers:

• Aqueous humour — watery fluid filling the space between cornea and lens (anterior chamber).
• Vitreous humour — thick, jelly-like fluid filling the space between lens and retina (posterior chamber), maintaining the eyeball's shape.

Inner (nervous) coat: …