Is there a neat way to do contextual logging in a concurrent system?

Why is the lymphatic system a one way system?

• explain why the system is a one-way system, whereas the blood vascular system is a two-way system

• Answer:

  The blood system is obviously continuous (from the heart through the arteries to the capillaries and back through the veins to the heart). This is why its called two way, it goes out then back again. When in the capillary beds much of the blood plasma is lost from the system into the intersticial space (the space between the cells). When this builds up it can create too much pressure for the cells. The job of the lymphatic system is to remove the excess fluid from these spaces. So the vessels of the lymphatic system carry the blood from its own capillary-bed-like regions to the Right Lymphatic Duct and the Thoracic Lymphatic Duct which replace the fluid lost from the blood into the left and right Subclacian Veins. This is why its called one way, it carries fluid only in the return direction.