3D Model: 3D Video Animation Of A Human Vein. The Camera Is Positioned To The Side Of The Vein. The Background Features Subtle Biological Details. Initially, Blood, In The Form Of Red Blood Cells, Flows Through A Thin Vein. At The 2-second Mark Of The Video, The Vein Walls Rapidly Expand In Thickness, And The Vein Becomes Large And Wide Along Its Entire Length. Consequently, The Red Blood Cells Begin To Flow Faster Through The Expanded Vein.