The anatomical features of the respiratory system in the human body include the airways, lungs and the respiratory muscles. The respiratory system can be divided in to upper respiratory tract and lower respiratory tract based on the anatomical features. The upper respiratory tract includes the nasal passages, larynx, while the lower respiratory tract comprises of the trachea, primary bronchi and lungs.

The primary function of the respiratory system is to supply oxygen to the blood to be distributed to other parts of the body. This happens through breathing in which inhale of oxygen and exhale of carbon dioxide happens. Molecules of oxygen and carbon dioxide are passively exchanged by diffusion between the gaseous external environment and blood. This exchange of gases in the respiratory system means inhaling oxygen in the blood which happens in the alveolar region of the lungs.

The respiratory system remains dormant as a fetus during pregnancy and becomes functional at birth, although some development and growth continues throughout childhood. A pre-term birth can lead to infants with under-developed lungs. Smoking and air pollution are two main causes of respiratory problems. The respiratory tract is constantly exposed to microbes because of the large surface area that is why respiratory system has many mechanisms to prevent pathogens from entering the body.

The disorders related to the respiratory system can be put in four categories:

1. Obstructive Pulmonary Conditions: Irritation of the lungs can cause emphysema, bronchitis and asthma attacks and people can develop two of these together
Chronic Bronchitis: Bronchitis is a condition in which any irritant reaching the bronchi or bronchioles stimulate secretion of mucus, in a chronic condition air passages become clogged with mucus which leads to persistent coughing
Emphysema: This is a condition in which delicate walls of the alveoli break down which reduces gas exchange area between lungs
Asthma: It is a condition in which periodic constriction of bronchi or bronchioles makes breathing difficult

Treatment of Obstructive Pulmonary Conditions involves certain goals and strategies:

Prevention of further deterioration of lung infection - this includes cessation of cigarette smoking, medications to dilate airways and decrease airway inflammation
Alleviation symptoms - vaccination against influenza and pneumonia
Improvement in performance of daily activities and quality of life - oxygen supplementation, pulmonary rehabilitation


2. Restrictive Conditions - This includes fibrosis, sarcoidosis, alveoloar damage, pleural effusion
3. Vascular Diseases - This includes pulmonary edema, pulmonary embolism, pulmonary hypertension
4. Infectious and other Environmental Diseases: This includes pneumonia, tuberculosis, asbestosis, particulate pollutants
Pnuemonia - It is an infection of the alveoli which can be caused by both by many kinds of bacteria and virus. In this condition tissue fluid accumulate in the alveoli which reduces the surface area exposed to air which may even require supplemental oxygen for the patient
Treatment involves oral antibiotics, rest, fluids and home care which are sufficient to treat the disease. In severe cases of pneumonia in which patient has trouble breathing, people with other medical problems or elderly may require advanced treatment.

Diseases of the respiratory system are usually treated by a pulmonologist or respiratory physician.