Macrophotograph of stinging hairs on the stem & leaves of a stinging nettle,Urtica dioica. The stings are long hairs with silicified tips which break off when the nettle is brushed against or stroked. The sting penetrates the skin,injecting a mixture of acetylcholine & histamine; the former is a neurotransmitter substance normally produced at nerve terminals,the latter a chemical mediator normally produced by mast cells & responsible for many of the unpleasant symptoms of allergic reactions. Only the long hairs on the leaf are stinging hairs; the short ones are harmless. Magnification: X 1 (35mm size) | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Burgess, Dr. Jeremy |
Bildgröße: | 2480 px × 3815 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |