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.
Doctors: What does 'critically injured' mean? Does it mean you're more likely to live, or more likely to pass on? If you're a doctor, and you have just been told your family member is in 'critical condition' what runs through your mind? Are you weighing the odds? Are they 50\50 to the chance of survival?