Arteries and Veins

In the Name of Allah, The Most Gracious, Most Merciful
The story of arteries and veins in human body:
In His Miraculous Divine Book, the Holy Quran, Allah, All Mighty, says,
“And indeed We have created man, and We know what his own self whispers to him. And We are nearer to him than his jugular vein.”
[L; 16]
In the human body, there are arteries and veins. The arteries contain oxidized blood, i.e. blood that contains oxygen; and they divide into smaller and smaller branches so that they carry blood and food energy to each and every cell of the human body. Blood is in bad and constant need of oxygen; therefore, the veins carry blood to the heart, which, in turn, pumps it to the lungs where oxygen is needed.

In its journey from the foot to the heart, venous blood runs upwards, i.e. against the earth’s gravity. Therefore, there must be a way to keep the blood running upwards, and not downwards as necessitated by the force of gravity. Due to His Infinite Divine Wisdom and Creativity, the Maker, Allah, All Mighty, has made special valves for the veins that carry blood to the heart. These valves allow blood to go up, but they prevent it from going down. They are, in fact, pouches located on the internal walls of blood vessels. When blood is being pumped upwards, these pouches stick to the walls, allowing the blood to pass. But if blood moves downwards, these pouches swell with blood and block the interior cavity of the blood vessels, preventing blood from going down.

No, what do the valves, which Allah, Most Gracious, has made in the veins, do? The answer is: They allow blood to run in only one direction, upwards.
If anything went wrong with these valves and failed to prevent blood from going down, blood would gather in the veins and cause a lot of pressure therein, the red blood corpuscles would get out through the walls of veins to the tissues, legs would become blue, swollen and very painful. This is what medical doctors call “varicosity”.
Look at this marvelous creation:
In brief, these valves do a really marvelous job! In this context, Allah, Most Gracious, says,
“Verily, We have created man in the best stature.” [XCV; 4,6]
Praise be to Allah, the Lord of Creations