Cigarette smoking harms the body by raising cholestrol levels and blood pressure, as well as increasing the risk of cancer and cataracts. Smoking destroys certain vitamins and creates the need for other specific nutrients.
{"Addictive substances: Nicotine," Lets Live Magazine, Oct. 1996}

Smokers are 4 times more likely to have gray hair and increased hairloss (British Medical Journal, Science News, Jan. 11, 1997}

No amount of smoking is free of risk. The exact amount of risk depends on how long you've smoked and how deeply the you inhale, as well as genetic factors. (UCBerkeley Wellness Letter, June 1998}

Smoking is associated with a decline in physical function that makes a smoker act several years older than he/she really is. Tobacco smoking reduces the effectiveness of medications, such as pain relievers, antidepressant , tranquilizers, sedatives, ulcer medication and insulin. With estrogen and oral contraceptives, smoking may increase the risk of heart and blood-vessel disease. Currently, smoking kills 1 in 10 adults worldwide.
{Information Plus - The Information Series on Current Topics, "Alcohol and Tobacco, America's Drugs of Choice," 1998}

Smoking makes tinnitus worse, says Dr. Harold Pillsbury, University of NC, Professor of Surgery and Otolaryngology.
{People's Pharmacy, Public Radio, July 24, 1999}

Other research shows that smokers have an increased risk of heart disease (including stroke, chest pain and palpitations), cancer, emphysema,fatigue, loss of vitamins and nutrients, premature aging, gastrointestinal disorders, osteoporosis sinus congestion and throat irritation. According to medical reports, colds,flu and laryingitis last much longer for those who smoke.

Smoking causes an increased stress in the whole body even though there seems to be a lessening of stress when the body gets its 'fix' from the nicotine. Dr. Norman Shealy, a physician with the Shealy Institute for Comprehensive Pain and Health Care in Springfield, MO, tells us that smokers tend to consume other drugs and chemicals more frequently than nonsmokers, and have a lower threshold for pain, possibly because smoking stimulates adrenaline and also blocks one of the body's natural pain relievers. Smokers are more vulnerable to headaches.

The global economy faces a number of serious challenges in the 21st Century. Globalisation has benefitted most participants, but the increasing interconnectedness of the global economy has created a number of problems.

Some global problems are short term, such as the recent recession caused by the credit crunch and related banking crisis. Most global shocks are relatively short term and may be self-correcting.  Other apparently short run events can have long lasting effects, such as the oil shocks of the 1970s, which permanently altered the global market for oil.

The Pathway

• Air enters the nostrils
• passes through the nasopharynx,
• the oral pharynx
• through the glottis
• into the trachea
• into the right and left bronchi, which branches and rebranches into
• bronchioles, each of which terminates in a cluster of alveoli

Only in the alveoli does actual gas exchange takes place. There are some 300 million alveoli in two adult lungs. These provide a surface area of some 160 m² (almost equal to the singles area of a tennis court and 80 times the area of our skin!).  

Breathing

In mammals, the diaphragm divides the body cavity into the

• abdominal cavity, which contains the viscera (e.g., stomach and intestines) and the
• thoracic cavity, which contains the heart and lungs.

The inner surface of the thoracic cavity and the outer surface of the lungs are lined with pleural membranes which adhere to each other. If air is introduced between them, the adhesion is broken and the natural elasticity of the lung causes it to collapse. This can occur from trauma. And it is sometimes induced deliberately to allow the lung to rest. In either case, reinflation occurs as the air is gradually absorbed by the tissues.
Because of this adhesion, any action that increases the volume of the thoracic cavity causes the lungs to expand, drawing air into them.

• During inspiration (inhaling),
  • The external intercostal muscles contract, lifting the ribs up and out.
  • The diaphragm contracts, drawing it down .
• During expiration (exhaling), these processes are reversed and the natural elasticity of the lungs returns them to their normal volume. At rest, we breath 15–18 times a minute exchanging about 500 ml of air.
• In more vigorous expiration,
  • The internal intercostal muscles draw the ribs down and inward
  • The wall of the abdomen contracts pushing the stomach and liver upward.
  Under these conditions, an average adult male can flush his lungs with about 4 liters of air at each breath. This is called the vital capacity. Even with maximum expiration, about 1200 ml of residual air remain.

The table shows what happens to the composition of air when it reaches the alveoli. Some of the oxygen dissolves in the film of moisture covering the epithelium of the alveoli. From here it diffuses into the blood in a nearby capillary. It enters a red blood cell and combines with the hemoglobin therein.
At the same time, some of the carbon dioxide in the blood diffuses into the alveoli from which it can be exhaled. 

sumber: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Pulmonary.html