tiredness fatigue有何区别?

fatigue:great tiredness,usu resulting from hard work or exercise 疲乏; 疲劳; 疲倦:We were all suffering from fatigue at the end of our journey.我们到旅程终点时全都累垮了.
tire:(cause a person or an animal to) become weary or in need of rest （使人或动物）疲劳,疲倦:She's got so much energy she never seems to tire.她精力充沛--似乎从不感到疲倦.* Old people tire easily.老年人容易疲倦.* The long walk tired me (out).我长途步行之后很累.