Blood drop

The average human adult has more than 5 liters (6 quarts) of blood in body.
Blood carries oxygen and nutrients to living cells and takes away their waste products.
It also delivers immune cells to fight infections and contains platelets that can form a plug in a damaged blood vessel to prevent blood loss.

Blood contains
55% : Plasma
1% : White blood cells & platelets
44% : Red blood cells

Red Blood Cells
A drop of blood the size of a pinhead contains approximately 5 million red blood cells (erythrocytes).

White Blood Cells
There are between 6,000 and 8,000 white cells per cubic millimetre of blood.

Just one drop of blood contains about 10,000 white blood cells (ranges between 7000 to 25000) and 250,000 platelets.