Allergy is an extravagant reaction in immune system in response to exposure to certain foreign substances. The response is embellished because these foreign substances are normally seen as harmless by the immune system. In allergic patients, the body recognizes the substance as foreign, and the allergic part of the immune system generates a response. Asthma is a chronic disease that comprises the airways in the lungs. These bronchial tubes, airways allow air to inhale and out of the lungs. Symptoms include shortness of breath, cough, wheezing, and chest tightness. The diagnosis of asthma is based on indication of wheezing and is confirmed with breathing tests. Many allergens and irritants precipitate attacks of asthma upto a greater extent. Avoidance of precipitating factors can be helpful.

Chronic obstructive pulmonary disease is characterized as a lung disease caused by chronic obstruction of lung airflow that interferes with normal breathing and is not fully reversible. Chronic obstructive pulmonary disease (COPD), includes emphysema and chronic bronchitis this makes difficulty in breathing. Pneumonia is a form of acute respiratory infection that affects the lungs ranging from mild to severe cases. Pneumonia is a bacterial, viral, and fungal infection of one or both sides of the lungs that causes the air sacs, or alveoli, of the lungs to fill up with fluid or pus. Symptoms can be mild or severe and may include a cough with phlegm, fever, chills, and trouble breathing.

Respiratory and sleep medicine is the diagnosis and treatment of diseases of the lungs and respiratory system. Sleep medicine is a multidisciplinary field with contributions by practitioners and researchers in many disciplines. Sleep medicine is a subspecialty in the field of medicine related to the diagnosis and therapy of sleep disturbances and disorders. Pulmonary medicine has important contributions to the field of sleep medicine for many years in babies, children and teens with conditions that affects breathing and sleep. Respiratory medicine is the branch of internal medicine that focuses on the prevention, diagnosis and management of disorders of the respiratory system, including the thoracic cavity, lungs, upper airways and chest wall.

The Respiratory care provides quality care to patients of all ages who suffer from deficiencies and abnormalities of the cardio-pulmonary system. Pulmonary care is the science concerned with the anatomy, physiology, and pathology of the lungs. It deals with many diseases and conditions like acute respiratory distress syndrome, asthma, cystic fibrosis, interstitial lung disease, lung cancer, lung transplants, chronic obstructive pulmonary disease, occupational lung disease, pulmonary hypertension, pulmonary tuberculosis, sarcoidosis of severe acute respiratory syndrome. Respiratory Care can be defined as a health care discipline that specializes in the promotion of optimum cardiopulmonary function of health and wellness. Respiratory Therapists employ scientific principles to identify, treat and prevent dysfunction of the cardiopulmonary system.

Cell structures of lungs contain many different types of cells. Most cells in the lung are epithelial cells. Epithelial cells are situated in the airways and mucus, which lubricates and protects the lung.

Any kind of defect in the epithelial cells leads to severe cases. Lung disease is one of the major leading causes of death in worldwide. Current treatments are focused on improving the quality of life of lung disease patients by reducing inflammation or pharmacologically inhibiting disease specific pathways. The human lung consists of different cell types with highly specialized structure and functions. The portfolio of primary human pulmonary cell types allows modelling the characteristics of each cell type to investigate their role in developmental biological processes, pharmacological studies, and disease diagnosing.

The basic contrivances involved in body's defence to recognize the remedy for manipulation of the immune system to provide protection against diseases, disease causing organisms and understand mechanisms behind it; that can be used to target disease processes for intervention is known as immunology. Respiratory medicine is apprehensive treatment with the diagnosis and treatment of a wide variety of diseases of the airway and lungs, their linings and blood vessels, and the muscles and nerves required for breathing. Bronchodilators, corticosteroids, mast cell stabilizers and anti-IgE antibodies, leukotriene receptor antagonists, antihistamines and epinephrine are most commonly used respiratory medicines.

New-borns and young children have a higher metabolic rate and rate of consumption of oxygen per unit body weight than adults as they have a larger surface per unit body weight and because there an increase in the rate of paediatric mortality rate in today’s generation. Paediatric respiratory medicine can be termed as multidisciplinary subspecialty in the branch of medicine that deals within the specialty of paediatrics, involving respiratory physiologists, physiotherapists, doctors, nurses including the parent. The advent of powerful new therapies are invented in case of paediatrics which includes particular antibiotics and anti-inflammatories that has led to the requirement for better monitoring tools. Bronchoscopes are small enough to examine the preterm babies, and novel physiological testing in paediatrics. Specific future challenges are dealt with specific disease areas, and monitoring tools paediatric intensive care.

Pathogens play main role in causing lung infections. Several microorganisms collect the harmful pathogens in a person's air sacs and begin to grow. The air sacs may become filled with phlegm, pus and fluid, that causes difficulty in breathing. It leads to chest pain, cough that is different from the usual chronic cough one associates with their disease. The primary types of lung infections are pneumonia, bronchiolitis and bronchitis. These conditions are typically caused by bacteria and viruses. Fungal infections are usually more common in people who have weakened immune systems. Respiratory failure occurs when fluid builds up in the air sacs in your lungs. It’s the condition in which lungs can’t release oxygen into blood.

Cardiopulmonary disease is described as range of serious disorders that affects both heart and lungs chronic inflammatory lung disease that results in the obstruction of airflow through the lungs. The symptoms of this condition include coughing, trouble breathing, and wheezing. While this is not always the case and while causes can vary, the most common cause of COPD is smoking. In addition to cardio pulmonary disorders, individuals who smoke long-term initiate a risk of developing other health conditions, including heart disease and lung cancer. Cardiopulmonary disease is described as range of serious disorders that affects both heart and lungs chronic inflammatory lung disease that results in the obstruction of airflow through the lungs. The symptoms of this condition include coughing, trouble breathing, and wheezing.

Interventional pulmonology is a growing medical field from its parent specialty of pulmonary medicine. It deals specifically with minimally percutaneous and invasive endoscopic procedures for diagnosis, treatment and mitigation of neoplastic as well as non-neoplastic diseases of the airways, lungs, and pleura and other organs in the body. It is mainly defined as a role of bronchoscopy in the evaluation and treatment of respiratory diseases. Thoracic surgery focuses on the chest organs, including the heart, lungs, oesophagus, and trachea. Technological advances have increased the safety and availability of these complex surgical procedures as heart transplants, anti-reflux surgeries and lung cancer surgeries, save and improve lives.

Occupational lung diseases are defined as a vast group of diagnoses caused by the inhalation of chemicals, dusts, or proteins. The inhalation of certain agents causes an acute injury to the respiratory tract of varying severity. Occasional acquaintance to high levels of organic dusts, fumes that contaminated with microorganisms and endotoxins may lead to fever and organic dust toxic syndrome. These inhalation fevers are the clinical expressions of a relatively transient and benign condition of intense pulmonary inflammation. Pulmonary Hypertension is the elevation of pressure in the pulmonary vessels. The condition is common in pre-existing pulmonary diseases; it varies in certain conditions and cause pulmonary fibrosis.

Respiratory medicine encompasses a wide variety of patient care opportunities and offers a large spectrum of practice opportunities. The majority of critical care specialists enjoy a practice that provides care for both inpatients and outpatients. Inpatient care involves unsympathetically ill patients with multiorgan system disease and requires the ability to synthesize large amounts of data while also coordinating care with other disciplines as an interdisciplinary endeavour. While the majority of critical care practitioners work in general intensive care unit settings, providing care for a wide variety of patients, some specialists choose to specialize even further in neurological units and cardiac units. Thus there are many options to tailor one’s practice to fit a desired work-life balance.

Respiratory Epidemiology is illustrated as a field of an interdisciplinary group of investigators who study the epidemiology and health outcomes of pulmonary conditions in an individual; to identify risk factors, in particular environmental conditions and occupational factors, adverse and beneficial health outcomes. Public health is the discipline of protecting and improving the health of people and their communities. It is achieved by endorsing healthy lifestyles, researching disease and injury prevention, and detecting, preventing and responding to infectious diseases.