DID you know that if you took all the blood vessels out of an average child and laid them out in one line, the line would stretch over 60,000 miles (100,000 kms)? An adult’s would be closer to 100,000 miles (160,000 kms) long. In contrast, the entire earth’s circumference is only about 40,075 km.
Can you imagine the 5-6 ft body of ours has so many “wires” connecting and keeping our body parts operating without getting entangled and perfectly fitted inside us? They also come in different sizes, ranging from a diameter of 25 millimeters to only 8 micrometers.
Subhan Allah, how amazing is Allah’s creation! One can only feel pity for the scientists who witness the perfect creation and still deny the Creator. No one would ever accept that a phone or a car, something far less marvelous, did not have a designer or manufacturer. Yet they deny the miraculous signs of creation all around us.
Our blood vessels are of three kinds: arteries, veins, and capillaries. Each plays a very specific role in the circulation process.
Arteries carry oxygenated blood away from the heart. They’re tough on the outside but they contain a smooth interior layer of epithelial cells that allows blood to flow easily. Arteries also contain a strong, muscular middle layer that helps pump blood through the body.
Capillaries connect the arteries to veins. The arteries deliver the oxygen-rich blood to the capillaries, where the actual exchange of oxygen and carbon dioxide occurs. The capillaries then deliver the waste-rich blood to the veins for transport back to the lungs and heart.
Veins carry the blood back to the heart. They’re similar to arteries but not as strong or as thick. Unlike arteries, veins contain valves that ensure blood flows in only one direction. (Arteries don’t require valves because pressure from the heart is so strong that blood is only able to flow in one direction.) Valves also help blood travel back to the heart against the force of gravity.