1

Scanning electron micrograph of Gastro-intestinal mucosa of a normal healthy adult individual (control) showing;-

► columnar cells studded with microvilli on the cell surface.The microvilli are responsible for absorbing nutrients on the cell surface.

► The white mass spread around the mucosa is the mucus which helps in comfortable bowel movement.

2

Scanning electron micrograph of Gastro-intestinal mucosa of an individual suffering from "non-ulcer dyspeptic" complaints; consuming water contaminated with 1.2 ppm (mg/l) of Fluoride.

Note: The columnar cell surfaces are exposed (naked) as:

► microvilli are lost ► presence of scanty microvilli

► very little mucus secretion seen on the mucosal surface.

3

Scanning electron micrograph of Gastro-intestinal mucosa of an individual suffering from non-ulcer dyspeptic complaints; consuming water with 3.2 ppm (mg/l) of Fluoride.

Note: The columnar cell surfaces are exposed (naked) and appear:

► cracked ► no microvilli ► no mucus secretions are seen.