The Respiratory System

The respiratory system consists of organs, tissues, and structures that exchange gases between the body and its surroundings. Its main role is to bring oxygen into the body and remove carbon dioxide. Gas exchange involves two stages: external and internal respiration. External respiration occurs in the lungs’ tiny air sacs, called alveoli, where oxygen from inhaled air enters the blood and carbon dioxide moves from the blood into the lungs to be breathed out. Internal respiration involves gas exchange between the blood and body tissues, delivering oxygen to cells and carrying away the carbon dioxide they produce.

Several illnesses and conditions can interfere with respiratory function. Infections such as the common cold, influenza, bronchitis, pneumonia, and tuberculosis affect different parts of the respiratory tract and may cause inflammation, coughing, and breathing difficulties. Asthma is a chronic condition in which the airways become inflamed and narrow, causing recurring wheezing, coughing, chest tightness, and shortness of breath. Chronic obstructive pulmonary disease (COPD), often associated with prolonged exposure to tobacco smoke or other irritants, causes persistent airflow limitations and can involve chronic bronchitis and emphysema. A pulmonary embolism occurs when a blood clot blocks an artery in the lungs. This potentially life-threatening condition can cause chest pain, sudden breathlessness, and low blood oxygen levels.

Allergies such as hay fever, also known as allergic rhinitis, can inflame the nasal passages and cause respiratory symptoms. Lung cancer, frequently associated with smoking or exposure to cancer-causing substances, may cause a persistent cough, chest pain, shortness of breath, and unexplained weight loss. Respiratory failure occurs when the lungs cannot supply enough oxygen or adequately remove carbon dioxide and requires immediate medical attention. Sleep apnea causes repeated interruptions in breathing during sleep, which can lead to daytime sleepiness and increase cardiovascular risks when untreated.