Some substances are more toxic than others. The toxicity of a substance is described by the types of effects it causes and its potency. 1  Types of Effects: Different chemicals cause different effects.
I think I remember reading that injured means bruises and lascerations, seriously injured meant hospital but not life threatening, critically injured meant hospital ICU time and fatally injured meant injuries leading to dying sometime later.
1 The definition of a nosebleed is simply bleeding from the blood vessels in the nose. The medical term for nosebleed is epistaxis.  Nosebleeds are common due to the location of the nose on the face, and the large amount of blood vessels in the nose.