health:MEDICAL EMERGENCIES p2

Severe Bleeding
Severe bleeding from any major blood vessel in the body is extremely
dangerous. The loss of 1 liter of blood will produce moderate symptoms
of shock. The loss of 2 liters will produce a severe state of shock that
places the body in extreme danger. The loss of 3 liters is usually fatal.
Shock
Shock (acute stress reaction) is not a disease in itself. It is a clinical condition
characterized by symptoms that arise when cardiac output is insufficient
to fill the arteries with blood under enough pressure to provide
an adequate blood supply to the organs and tissues.