A lot
A normal adult human body typically has 1.25 - 1.30 gallons, (10 pints) of blood. These measurements can vary, due to size and sex.
5 qts.
11/2 to 2 liters, 3 to 31/2 pints.Between 2 & 4 litres per day is safe!
It depends on the size of the point of the instrument doing the puncturing (i.e. a needle takes only a little force, but a bullet takes quite a bit). What you really need is how much pressure does it...