Breathing In (Inhalation)
When you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. This increases the space in your chest cavity, into which your lungs expand. The intercostal muscles between your ribs also help enlarge the chest cavity. They contract to pull your rib cage both upward and outward when you inhale.
As your lungs expand, air is sucked in through your nose or mouth. The air travels down your windpipe and into your lungs. After passing through your bronchial tubes, the air finally reaches and enters the alveoli (air sacs).
Through the very thin walls of the alveoli, oxygen from the air passes to the surrounding capillaries (blood vessels). A red blood cell protein called hemoglobin (HEE-muh-glow-bin) helps move oxygen from the air sacs to the blood.
At the same time, carbon dioxide moves from the capillaries into the air sacs. The gas has traveled in the bloodstream from the right side of the heart through the pulmonary artery.
Oxygen-rich blood from the lungs is carried through a network of capillaries to the pulmonary vein. This vein delivers the oxygen-rich blood to the left side of the heart. The left side of the heart pumps the blood to the rest of the body. There, the oxygen in the blood moves from blood vessels into surrounding tissues.
(For more information on blood flow, go to the Health Topics How the Heart Works article.)
Breathing Out (Exhalation)
When you breathe out, or exhale, your diaphragm relaxes and moves upward into the chest cavity. The intercostal muscles between the ribs also relax to reduce the space in the chest cavity.
As the space in the chest cavity gets smaller, air rich in carbon dioxide is forced out of your lungs and windpipe, and then out of your nose or mouth.
Breathing out requires no effort from your body unless you have a lung disease or are doing physical activity. When you're physically active, your abdominal muscles contract and push your diaphragm against your lungs even more than usual. This rapidly pushes air out of your lungs.
The animation below shows how the lungs work. Click the "start" button to play the animation. Written and spoken explanations are provided with each frame. Use the buttons in the lower right corner to pause, restart, or replay the animation, or use the scroll bar below the buttons to move through the frames.
Answer:
4 weeks
Explanation:
It takes about 4 weeks for you to start feeling the changes
It also takes 8 weeks for friends to notice the changes
Finally, It takes about 12-15 weeks for the world to notice the huge changes
FIVE MINUTES by Matt Barton
The masked man put it simply: "I'm going to kill you in five minutes," and since James had heard him say the exact same line to three of his friends--and noted with some alarm that the man had carried through on each occasion--he knew exactly what lay in store for him. He was tied down with barbwire to a rough sawed plank, but comfort mattered little now. After all, the last thing he wanted to do with his last five minutes was think about how uncomfortable he was on that stupid board. You'd think, though, that someone would've at least sanded it down a bit. And why barbwire? Was that really necessary? Why couldn't he have been killed by a killer who preferred soft nylon rope? And why, for that matter, had he been positioned facing the wall, with nothing interesting to look at? He was the only one of his friends who'd been put this way. Nothing to see but cheap wood grain paneling. It was maddening. What an insult! And, to make matters worse, he had to pee. He didn't mind not getting a "last cigarette." He didn't smoke. But he did have to pee. Jesus Christ, what a lousy way to spend five minutes.
<span>The answer is opening, wide. Employers must guard employees from three types of hazards. These include a floor opening that is large enough for a person to fall into, a floor hole that is large enough and wide enough for small items to fall into, and a wall opening that is large enough for a person to fall through and is at least 4 feet above the ground. </span>
