"Stinging nettle leaf, SEM" - Vídeo de stock HD

"Animated scanning electron micrograph (SEM) of the leaf of a stinging nettle (Urtica dioica), pulling back to show one of its stinging hairs. This plant has many hollow stinging hairs called trichomes on its leaves and stems. They act like hypodermic needles, injecting histamine and other chemicals that produce a stinging sensation when contacted by humans and other animals. Despite this defence, the stinging nettle has a long history of use as a medicine and as a food source."