Blood viscosity?

Answer 1

Yes, it is a bit viscous.

"Blood consists of plasma and particles, such as the red blood cells. The viscosity of blood thus depends on the viscosity of the plasma, in combination with the hematocrit (Ht). Higher hematocrit implies higher viscosity. The relation between hematocrit and viscosity is complex and many formulas exist. One of the simplest is the one by
Einstein:
h = h(plasma) (1 + 2.5 Ht)
The viscosity of plasma is about 0.015 Poise (1.5 cP) and the viscosity of whole blood at a physiological hematocrit of 45 is about 3.2 centipoise (cP) , or 3.2 10-3 Pa.s."