Part 1: In this part of the talk we will discuss the coil-stretch hysteresis in dilute polymer solutions for extension dominated flows, including three-dimensional mixed flows. We will then turn to entangled systems and discuss the role of slip-link simulations in elucidating the extensional behavior in concentrated solutions and melts. Part 2: Platelets are 7 times more likely to be at the periphery of the flow through microtubules than red blood cells above 35% hematocrit. The transport mechanism by which this occurs can be elucidated through dynamic simulation. In particular we will look at the effect of hematocrit and shear rate on these dynamics