So, capillaries are very tiny blood vessels that are one cell layer thick. They contain a single layer of endothelial cells that is responsible for absorbing and secreting the nutrients and the waste products between the lumen of the capillary and the cells, the tissues found in close proximity to those capillaries. So arterioles connect to the venues via these capillaries. Now, hydrostatic pressure forces the cells of our body. And as blood travels, hydrostatic pressure for I'm sorry, capillaries run close to the cells of our body. And when the blood travels through the lumen of the capillary, hydrostatic pressure basically forces the nutrients and our waste products to move back and forth between the lumen and the cells fan around that capillary.