If I tried to put an ad in the newspaper announcing houses that come with self-manufacturing plumbing and electrical systems, they would tell me I was writing science fiction, and refuse to print it. If I tried to have it printed in a science magazine, they would laugh in my face. But that is what your body does. Before you were born, it constructed its own plumbing and electrical system-and more besides.
Your body is filled with plumbing; in fact, with several totally different plumbing systems. These include your circulatory system, which sends blood all over your body, your urinary system, which purifies the blood, and your lymphatic system, which carries on additional cleaning actions in body tissues. There are also compact plumbing systems in the liver, kidneys, mammary glands, skin sweat and oil glands, and the endrocrine glands.
Your circulatory system is composed of a blood pump (your heart), and the plumbing (blood vessels) needed to carry fluid (blood) throughout your body.
The structure of the heart is another great marvel. It is perfectly designed for what it must do, and is the hardest working muscle in your body.
In the wall of the right atrium of the heart is a small spot of tissue. Called the sino-atrial (SA) node, approximately every second this tissue send out a tiny electrical signal which special nerves quickly carry throughout the heart muscle in the right ventricle. The message it sends is: “Beat!” Instantly, a second node, the atrioventricular (A V) mode (bundle of His) is alerted and relays the message on to the left ventricle: “Bead”
And your heart beats! Moment by moment, day by day, year by year, it keeps beating. How thankful are you for that beating heart?
The heart is a powerful pump that drives 5 to 6 quarts [4.7-5.7 liters] of blood per minute through several miles of tubes in your body. During active exercise, this can go up to 20 quarts ]19 liters]. Consider the complicated, yet efficient design of the pump:
Blood from all parts of your body returns through the superior and inferior vena cava (the largest veins in your body) and enters a “waiting room,” the right atrium (right auricle), ready to enter the right ventricle. When the next heart beat occurs, the ventricles squeeze. The load of blood already in the right ventricle is squeezed out into the pulmonary artery (and is sent to the lungs for oxygen). None of that blood flows back into the ventricle, because the semllunar valve guards the exit. That same squeeze brought the waiting blood from the right atrium through the tricuspid valve into the right ventricle. That valve keeps it from flowing back into the right atrium.
Blood returning from the lungs passes through four pulmonary veins into the left atrium (left auricle). A mural (bicuspid) valve guards the entrance into the left ventricle. Then comes the next heartbeat which sends that blood into the left ventricle,-a split second after the blood in the ventricle has been squeezed out through the semilunar valve into the aorta (the largest artery in your body).
The blood in the aorta goes to all parts of your body. From the aorta, that crimson stream is carried to still smaller arteries, and thence into arterioles. These flow through capillaries so tiny that the blood cells must pass single file. As they do, oxygen and nutriments pass across into the cells, while carbon dioxide and wastes leave the cells and pass out into the capillaries. Still other wastes pass out into the lymph vessels to be carried away. From the capillaries, the blood passes into venules, then into veins, then into the inferior or superior vena cave, and back to the heart. Random activity of molecules is supposed to have invented all that? Why, the organism would be long dead before “natural selection” ever got started trying to figure out such complication! Natural selection is simply random activity, and nothing more; it does not have the brains to accomplish anything worthwhile.
Your blood cells are very complex. In chapters 10 and 11 (DNA and Cells), we discuss part of the immense requirements needed to invent blood and other body cells. There are different types of blood cells; each one is vital and each one contains hundreds of key factors needed for life. Complicated enzymes must be present to produce the crucial ingredients in those cells.
One cubic centimeter-smaller than a drop of blood contains an average of 41/s-5 million red blood cells. They wear out in less than a month, and more are made in the red bone marrow. That same cubic centimeter of blood contains 7,0009,000 white blood cells, and increases to 15,00025,000 when infection occurs. There are several types of white blood cells. That same cubic centimeter of blood contains 250,000-500,000 blood platelets (thrombocytes). If you cut your finger, these are used to quickly clot the blood so you will not bleed to death.
The above description is over-simplified in the extreme. But it is enough to take one’s breath away! A Powerful, and extremely intelligent Being created you!