Researched by Kierea M.
2002-03

• PURPOSE 
• HYPOTHESIS 
• EXPERIMENT DESIGN 
• MATERIALS 
• PROCEDURES 
• RESULTS 
• CONCLUSION 

• RESEARCH REPORT 
• BIBLIOGRAPHY 
• ACKNOWLEDGEMENTS 

• ABOUT THE AUTHOR 

Breathing is a very important factor in living a long and healthy life. The respiratory system carries oxygen from the air into the body’s blood stream, and carries carbon dioxide out of the body. Without this there would be no human life. 
 
 

The respiratory system is one of the body’s amazing systems. Its main job is to collect oxygen from the air, transfer it to the body’s blood stream, and release carbon dioxide. A cell group in the brain called the "respiratory center" controls breathing. Every few second’s, nerve cells send a message to the lungs, telling them to inhale, breathing is an automatic reflex. There are two main parts of the respiratory system; the respiratory tract, which carries air in and out of the lungs, and the lungs themselves, which allow gas exchange.

Air is usually inhaled through the nose; this is where the respiratory tract begins. Connected to the nasal cavity is the pharynx, usually referred to as the throat. In the nose and throat there are tiny hairs called cilia. Cilia helps prevent dust in air from getting into the body, they also catch mucus. All the particles collected by the cilia are expelled from the body when a person sneezes, coughs, or blows their nose. The middle of the pharynx is connected to the back of the mouth.  Further down, the pharynx divides into two tubes, the esophagus, which is where the food goes and the larynx, into which the air goes.  The larynx, or voice box, creates a funnel that connects the throat to the trachea, or windpipe. The trachea then branches off into tiny airways called bronchi. Bronchi then branch off into smaller, microscopic airways called bronchioles that then connect to the lung’s alveoli.

There are two lungs, one on each side of the heart. When a baby is born, the lungs are light pink. By the time one reaches adulthood, the lungs have changed into a grayish tone. This can be caused by many different factors including unclean air. The lungs take up most of the chest area, expanding from the diaphragm, up to the collarbone. The inner surface areas of the lungs are 35 times larger than the person’s skins surface area. The lungs rest on the diaphragm, which moves up and down, causing them to inhale and exhale. The lungs 
 

are cone shaped with a spongy texture. The rib cage forms a protective 
structure around them. Inside the lungs there are pockets called lobes. There are three lobes in the right lung and two lobes in the left lung, allowing room for the heart. Inside the lobes, there are smaller pockets called lobules. The lobules are filled with microscopic air sacs called alveoli. The average adult has over three million alveoli in their two lungs combined. An alveolus has a thin moist inner surface, this is where gas is exchanged. The gas, which is mainly filled with carbon dioxide, is exchanged in place of the oxygen. When the gas is released, it goes through the respiratory tract, and out of the body.
 
 

Lung capacity is the maximum amount of air a person can contain in his or her lungs. It is measured in liters, using a pulmonary function machine. There are many different types and sizes of this machine. A smaller version of this machine is called the KoKo Peak. The KoKo Peak is a peak flow meter; it measures a person’s lung capacity. It takes two main measurements. The FEV1, which measures the first second of air blown out during forced exhalation. This is important because the most air is blown out during the first second of testing, giving an accurate estimate of a comparison. It also measures the FEV6, which is the total amount of air a person can blow out during forced exhalation in six seconds; this is the person’s actual lung capacity. 

When using this instrument you must stand, with the KoKo peak in your hand, making sure not to cover the vent holes.  While using this, make sure you are using a sanitary mouthpiece and a nose plug. Bring the mouthpiece close to your mouth, and then press the operation button. You will then hear a beep, take a deep breath in. After you hear a second beep, put the mouth around the mouthpiece and blow as hard and as fast as possible. After seven seconds the results will appear on the screen. 

Males’ lungs on average are larger than females’, causing the average male to have a larger lung capacity than the average female. There is no definite average for lung capacity. This is because the lung capacity of a person is dependant on many different variables.  These variables include size of lungs, weight, height, race, gender, and certain medical and physical conditions.
 
 

Lung disease kills millions of Americans each year. One of the most common lung diseases is cancer. The smoking of tobacco mainly causes this. Lung cancer kills more Americans each year than any other type of cancer. Smoking can also cause emphysema; which is where air vessels dilate, causing troubled or labored breathing.  Many different everyday chemicals or substances can damage the respiratory system. These chemicals and substances include car fumes, industrial smoke, household cleaning products, and worst of all cigarette smoke. Some symptoms of lung disorders may include, coughing, breathing difficulty, chest pain and or wheezing.
There are many other, less common, lung disorders. One type of lung disorder is pneumonia, which is where the lungs swell up, this is usually caused by bacteria and, or viruses.  Another, called pheumothorax, is where the lungs actually cave in. Pulmonary edema is a disorder where the lungs become filled with fluid. A similar disorder called pleural effusion is where the outer cover of the lungs, also known as pleura, fills with fluid. Pulmonary embolism, another disorder, is when a blood clot or other substances block pulmonary arteries, shutting of blood flow to the lungs. 

The respiratory system is one of the most important systems in the body. It needs to be taken care of. The respiratory system controls one’s ability to breath. Though on average a person only uses one fifth of their maximum capacity during normal breathing, without healthy lungs and respiratory tract, there would be no human life.

Burnie, David. The Consise Encyclopedia of The Human Body. U.S.: Dorling Kindersley. Pp. 110-115

"Gender" The World Book Encyclopedia.  1999. P.82

Human Anatomy. US: DK Publishing, 1996. Pp 20, 21 

"Lung" Microsoft Encarta Encyclopedia Deluxe 2002. 

Modell, Harold I. and Hildbrandt, Jack.   "Respiration," World Book Encyclopedia, 2001. Pp.523-528, 260 -261

Parker, Steve. Human body.  US, DK Publishing, 1993. Pp26, 27

Parker, Steve. The Lungs and Respiratory System Austin Texas. Raintree Steck-Vaughn Publishers, 1997. Pp.4-14.

Padilla, Maria Louis "Respiratory System" Microsoft Encarta Encyclopedia Deluxe 2001. 11/5/02

Smith, Bruce. Phone interview. 10/25/02

Smith, Bruce. Personal Interview. 11/11/02