Sinusoids
The splenic sinuses of the spleen, also known as sinusoids, are wide vessels that drain into trabecular veins. Gaps in the endothelium lining the sinusoids mechanically filter blood cells as they enter the spleen. Worn-out or abnormal red cells attempting to squeeze through the narrow intercellular spaces become badly damaged, and are subsequently devoured by macrophages in the red pulp. In addition to aged red blood cells, the sinusoids also filter out particles that could clutter up the bloodstream, such as nuclear remnants or denatured hemoglobin.
Read more about this topic: Red Pulp