Facts that we can see stimulate powerful motivation and curiosity. Even scientific findings from analysis of data become more influential when they are presented graphically. X-ray crystallography data expressed as 3D computer graphics make structural biochemistry a more exciting field. Ultrastructural morphologists have the privilege to see and think about new things years and decades before biochemists find ways to study the molecules. An unanticipated benefit from molecular biology is that analytic morphology has become more exciting as transgenic animals reveal how amplification or deletion of genes affect tissue and body structure.

The lymphocyte on the left is probing for a path between HEV endothelial cells. On the right, a 3D HEV drawing shows cell emigrants navigating between endothelial cells to enter perivenular channels en route to LN cortex.

To see polarity of migrating cells in vivo, Click on image.

to see larger version of Barbara Gould's drawing Click on image.

Selectins on a lymphocyte's microvilli cause it to slightly stick to endothelium and it slowly rolls along until integrin receptors at the tips are activated by chemokine to stick more firmly. The lymphocyte polarizes and begins squeezing into the space between two or more endothelial cells, as illustrated by the adjacent animation. Migrating lymphocytes crawl in vitro like worms. Intravital 2-Photon & electron microscopy shows them crawling like worms in vivo as well. Many molecular signals are involved in initiating Rolling, Tethering, Activation, Strong Adhesion, and Transmural Emigration. Lymphocytes in lumens may be triggered by combined effects of adhesion receptor binding and exposure of G-protein-linked serpentine receptors to diffusible chemokines anchored to endothelial cell glycocalyx. Chemokine signals displayed along vessel lumens markedly increase the range of cell-types selected to adhere and emigrate. This has to be how the immune system makes efficient cell cooperation possible.