"The Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul." Gen. 2:7
Body cells keep us alive by performing their various functions. To do this they need a constant supply of oxygen, and this supply begins when we inhale. As the air passes through the nose, it is warmed and moistened. If foreign particles are present, little hairs called cilia stop them. Sneezing or blowing the nose clears out these collected particles.
When we inhale, our two lungs stretch like balloons being filled with air. Then, in about two seconds, the lungs contract and the air is exhaled. This takes place about fifteen or twenty times a minute. Getting a sufficient quantity of oxygen from this air and into the bloodstream is the main function of the lungs. This is why they need fresh, clean air that is free of smoke, dust and fumes in order to maintain good health.
When expanded, the lungs have a surface of about two square feet for the air to pass over, but this is not enough to take care of their work. When God designed man's lungs, He wisely added to the lung capacity without making that organ huge and bulky. He did this by forming blood channels ending in tiny sacs all over the linings of the lungs. There are about six hundred million of these sacs, which increase the capacity of the lungs to six hundred to one thousand square feet (larger than many classrooms), which is three hundred times the capacity of the lungs alone! Each one of these tiny sacs brings blood to its surface. In the two seconds that air flows over these sacs, oxygen is transferred to the blood. This enriched blood moves on to the heart and is pumped throughout the whole body.
The lungs not only take oxygen out of the incoming air but also remove carbon dioxide from the blood. This carbon dioxide is a product of the body-cell processes and must be removed. The blood carries it to the lungs where it is expelled by the lung's exhaling action.
This entire process goes on without our thinking about it, except when we have a cold and have difficulty breathing. Only God could design and make our wonderful bodies and their remarkable details, which are the same today as when he created Adam and Eve in the garden of Eden. God, "in whose hand is the soul of every living thing, and the breath of all mankind" (Job 12:10), is always aware of everything pertaining to our lives. Have you ever thanked Him for His goodness in watching over you so carefully? "Let everything that hath breath praise the Lord" (Psa. 150:6).