Unique Delivery Service
Recent news casts have included stories about our postal delivery system and stolen parcels off the porches when packages have been left there. I have no personal complaints about either one of those, but what do you think about the excellent transport system described below?
- It includes about 120,000 km of pathways.
- It delivers life-sustaining nutrients.
- It picks up garbage on the same trip in the same vehicle.
- It serves about 60,000,000,000 customers, daily.
- About 1,200,000 “vehicles” wear out every second, after having made about 75,000 round trips during the 120 days of their ‘lives’, and are fully replaced.
The answer is our bloodstream, an incredibly well-designed delivery and retrieval system. Wikipedia claims that 2.4 million red blood corpuscles (the vehicles) are recycled and replaced, from the bone marrow factory, every second (others put it at 1.2M) – unbelievably amazing until you realize that there are over 5 million red cells in a microliter. A microliter is one millionth of a liter (a drop?). Blood is made up of red cells, white cells, platelets and soluble items like enzymes, sugar, salt, cholesterol, fats and plasma that requires water to maintain liquidity. There are actually two circulatory systems. The pulmonary system pumps ‘used’ blood to the lungs for releasing carbon dioxide and absorbing oxygen. The systemic one receives oxygen enriched blood from the lungs and pumps it out to the body. As the heart pumps the blood through the network, these very, very tiny red cells reach the capillaries, fold and twist to make it into and through those tiny passages. Their flexible, oval, biconcave shape makes this possible. There they unload oxygen and nutrients into the cells (customers) and pick up carbon dioxide and other wastes.
Should a cut or tear cause bleeding, platelets will be rushed to the location (do they have GPS?) in seconds to create a temporary patch. Then our body will use raw materials stored up for this purpose to make fibrin for complete healing.
Should disease or infections invade, antibodies will be dispatched that will fight to the death. Medicines aid that battle too. Much more could be said about this incredible system. What is our part in this? Eat healthy foods, drink enough clean water, exercise daily and monitor blood pressure. This marvelous system created for us will then serve us well.