Old at young !!!

As we keep our fingers in water for long time.....exosmosis pf water molecules from our hand cells occurs resulting in flaccidity of the cells and thus wrinkling of the skin!!!

The nervous system plays an essential role in wrinkling, so the phenomenon cannot be simply explained by water absorption. Wrinkling is related to vasoconstriction. Water probably initiates the wrinkling process by altering the balance of electrolytes in the skin as it diffuses into the hands and soles via their many sweat ducts. This could alter the stability of the membranes of many neurons that synapse on many blood vessels underneath skin,causing them to fire more rapidly. Increased neuronal firing causes blood vessels to constrict, decreasing the amount of fluid underneath the skin. This decrease in fluid would cause a decrease in tension, causing the skin to become wrinkly.