What kind of process is breathing

The chest cavity , or thorax pronounced: THOR-aks , is the airtight box that houses the bronchial tree, lungs, heart, and other structures.

The top and sides of the thorax are formed by the ribs and attached muscles, and the bottom by a large muscle called the diaphragm. The chest walls form a protective cage around the lungs and other contents of the chest cavity. The diaphragm pronounced: DYE-uh-fram , which separates the chest from the abdomen, plays a lead role in breathing.

When we breathe out, the diaphragm moves upward, forcing the chest cavity to get smaller and pushing the gases in the lungs up and out of the nose and mouth. When we breathe in, the diaphragm moves downward toward the abdomen, and the rib muscles pull the ribs upward and outward, enlarging the chest cavity and pulling air in through the nose or mouth.

Air pressure in the chest cavity and lungs is reduced, and because gas flows from high pressure to low, air from the environment flows through the nose or mouth into the lungs.

As we exhale, the diaphragm moves upward and the chest wall muscles relax, causing the chest cavity to contract. Air pressure in the lungs rises, so air flows from the lungs and up and out of respiratory system through the nose or mouth. Many factors — including genetics, pollutants and irritants, and infectious diseases — can affect the health of your lungs and respiratory system and cause respiratory problems. Problems of the respiratory system that can affect people during their teen years include:.

Asthma is a long-term, inflammatory lung disease that causes airways to tighten and narrow when a person with the condition comes into contact with irritants such as cigarette smoke, dust, or pet dander. In bronchitis, the membranes lining the larger bronchial tubes become inflamed and an excessive amount of mucus is produced. The person with bronchitis develops a bad cough to get rid of the mucus. Common cold. Colds are caused by over different viruses that cause inflammation in the upper respiratory tract.

The common cold is the most common respiratory infection. Symptoms may include a mild fever, cough, headache, runny nose, sneezing, and sore throat. A cough is a symptom of an illness, not an illness itself.

There are many different types of cough and many different causes, ranging from not-so-serious to life threatening. Some of the more common causes affecting kids and teens are the common cold, asthma, sinusitis, seasonal allergies, and pneumonia.

Cystic fibrosis CF. CF is an inherited disease affecting the lungs. CF causes mucus in the body to be abnormally thick and sticky. The mucus can clog the airways in the lungs and make a person more likely to get bacterial infections. Pneumonia is an inflammation of the lungs, which usually occurs because of infection with a bacteria or virus. Pneumonia causes fever, inflammation of lung tissue, and makes breathing difficult because the lungs have to work harder to transfer oxygen into the bloodstream and remove carbon dioxide from the blood.

Common causes of pneumonia are influenza and infection with the bacterium Streptococcus pneumoniae. Note: All information on KidsHealth is for educational purposes only.

For specific medical advice, diagnoses, and treatment, consult your doctor. All rights reserved. Find a Doctor. This site complies with the HONcode standard for trustworthy health information: verify here. Common Health Topics.

Respiratory muscles. Biology of the Lungs and Airways. Test your knowledge. Coughing up blood from the respiratory tract is called hemoptysis. Which of the following is the most likely cause of hemoptysis in adults? More Content. Click here for the Professional Version. Was This Page Helpful? Yes No. Defense Mechanisms of the Respiratory System. Breath-Holding Spells. Riot-Control Chemical Agents. Apnea of Prematurity. We can also breathe more forcefully. When we exercise, sing loudly or otherwise need or want more air or oxygen we can exert force to breathe more deeply.

We use various muscles to increase chest volume more dramatically. In the same way as in relaxed breathing the expansion of the chest cavity draws air in so the lungs fill up.

The relaxation of the chest cavity pushes air out. Muscles can also force the chest cavity to contract even further, pushing even more air out. Because the expansions and contractions are larger in this case a bigger volume of air flows in and out of our lungs, and our body gets a larger supply of oxygen or we have more air to create sound. Observations and Results When you pulled the knot back, the space inside the bottle increased and your balloon probably filled up with air.

In the same way, when the diaphragm in our body pulls back, the chest cavity increases and air flows into our lungs, and we inhale. When you pushed the knot in, the space inside the bottle decreased, and the balloon probably deflated. In the same way, when the diaphragm relaxes the chest cavity decreases, and air is pushed out of the lungs, and we exhale. When you pulled and pushed the knot further the balloon inflated and deflated more. This mirrors what happens when a bigger volume of air is displaced when we breathe more deeply.

This dynamic works because of air pressure, a measure of how hard air presses against objects. Air pressure increases when you decrease the amount of space the air has—and decreases when you give air more space.

Close a flimsy empty plastic bottle and try to compress it. It is difficult! The air inside pushes back. Open the bottle, and try to compress the bottle again. It is much easier. The air presses back with a much reduced force. Unless something blocks the movement, air will move from areas of high pressure to areas where the pressure is lower, and this is what happens when air rushes in or out of the lungs. When the chest cavity expands there is more space around your lungs.

In this condition the lungs can expand, making it a low-pressure area, and air rushes in to balance out the difference in pressure. Then to breathe out the chest cavity and lungs shrink. This raises the air pressure in your lungs, and the air rushes back out. This activity brought to you in partnership with Science Buddies. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue.

See Subscription Options. Go Paperless with Digital. Materials Disposable empty transparent bottle 10—16 fluid ounces made of hard plastic such as a sports drink bottle Ruler Two balloons 8-inch balloons work well Utility knife have an adult help and use caution when using the knife Adult helper Scissors Drinking straw optional Modeling clay optional Tape optional Additional balloon optional Preparation Ask an adult to cut the plastic bottle.

Place the cut bottle down on the wide opening. Lower a balloon into the bottle until only part of the balloon's neck sticks out. Fold the neck of the balloon over the top of the bottle. The balloon represents a lung.

Turn the bottle over keeping the balloon inside so the bottle top rests on the table.