Air passes through the lungs via branching airways that lead to air sacs, where gas exchange occurs. Bronchitis refers to inflammation of the lining of large to medium-sized airways, called bronchi.

Klebsiella bacterial infections cause symptoms that vary depending on the site of the infection. People often develop klebsiella infections because they have impaired immunity from being sick or required medical interventions.

Exercise plays an important role in keeping your body healthy and helping reduce your risks for diseases. However, exercise does not guarantee immunity, and illnesses such as the common cold or other bacterial or viral infections can often develop and get in the way of your regular exercise routine.

The National Library of Medicine (NLM) reports that there are over 1 billion colds in the United States per year, with children averaging 3 to 8 colds per year. Sinus infections are a common complication of colds. The sinuses are spaces of air created by the bones of the skull.

Little red bumps are a symptom of serious health conditions and not so serious health conditions. Little red bumps can be a sign of bacterial infections, viral infections, fungal infections or an over-active immune system. Each one of these conditions has its own set of accompanying symptoms.

Located in the very back of the mouth, wisdom teeth are the last to erupt and usually appear anytime from your late teens to mid-twenties. People normally have four wisdom teeth, according to the Better Health Channel, with one tooth on the top and bottom of each side of the mouth.

Viruses cause a broad array of human diseases. These microscopic particles spread easily, typically via person-to-person contact or touching contaminated surfaces. Once inside the body, viruses enter cells and reproduce quickly.

Viral infections affect many organs of the body. The skin is one such organ affected by viruses, either as the primary target or as a signal of ongoing systemic infections. The principal skin manifestation of a viral infection is a rash.

Your nails say a lot about how you take care of yourself. Peeling fingernails can be caused by harsh products, nail hygiene or the manner in which you are using your nails. According to Nia Terezakis, M.D.

If you suspect you have an ear infection, talk to your doctor. Infections need to be treated with antibiotics as soon as possible to prevent complications.

Scrapes occur when you come into contact with an object forcefully enough to remove part of the top layer of skin. Scrapes can easily become infected, as the source of a scrape is rarely a clean object.

A sinus infection occurs when the walls of the sinus cavity become inflamed, trapping mucus within the cavity, causing infection to set in, according to the Mayo Clinic. Most sinus infections are the result of seasonal allergies or the common cold.