The Respiratory System Overview

The Respiratory System

• The respiratory system is essential for life, responsible for gas exchange (oxygen and carbon dioxide).
• It involves inhalation and exhalation, also known as ventilation.
• The system is divided into two major tracts: the upper respiratory tract and the lower respiratory tract.
• Components of the upper respiratory tract include the nose, mouth, pharynx, epiglottis, larynx, and trachea.
• Components of the lower respiratory tract include the bronchial tree and lungs.
• The upper respiratory tract filters, warms, and moisturizes inhaled air.
• The nose has a nasal septum, dividing it into two sections, and cilia to remove debris.
• Mucous membranes line the respiratory tract, producing mucus to moisten and filter air.
• Olfactory receptors in the nose detect odors.
• Tonsils and adenoids are part of the lymphatic system, safeguarding the body from infections.
• Paranasal sinuses are air-filled cavities in the skull bones, making bones lighter and aiding in sound production.
• The pharynx (throat) is a shared passageway for air and food, with three divisions: nasopharynx, oropharynx, and laryngopharynx.
• The larynx (voice box) is situated between the pharynx and trachea, containing cartilage (including the thyroid cartilage or Adam's apple) and vocal cords.
• Protective mechanisms during swallowing include the epiglottis, which prevents food from entering the trachea, and the soft palate, which prevents food from entering the nasal cavity.
• The trachea (windpipe) is a tube that leads air to the bronchi, held open by C-shaped cartilage rings.
• Bronchi branch into smaller bronchioles, leading to alveoli (air sacs) in the lungs.
• Alveoli are surrounded by capillaries and facilitate gas exchange between air and blood.
• Pulmonary means relating to the lungs.
• Surfactant in the alveoli helps them remain stable and open, crucial for premature babies.
• The lungs are the essential organs for respiration, divided into lobes.
• The right lung has three lobes, while the left lung has two.
• The mediastinum is the middle section of the chest cavity containing the heart, blood vessels, esophagus, trachea, thymus gland, and lymph nodes.
• The pleura are thin membranes surrounding the lungs, including parietal pleura (outer layer) and visceral pleura (inner layer), which lubricates to prevent friction during breathing.
• The pleural cavity is the space between the parietal and visceral pleura.
• The diaphragm is a dome-shaped muscle separating the chest cavity from the abdomen, crucial for breathing.
• The phrenic nerves stimulate diaphragm contractions for inhalation.
• The only structure that passes through the diaphragm is the esophagus.

Medical Specialties Related to the Respiratory System

• An otolaryngologist (ENT) specializes in diseases and disorders of the head and neck, including the nose, throat, and ears.
• A pulmonologist specializes in diseases and disorders of the respiratory system (lungs).
• A thoracic surgeon performs operations on the organs within the chest cavity, including the heart, lungs, and esophagus.

Respiratory System Pathology

• Chronic obstructive pulmonary disease (COPD) is a group of lung diseases obstructing airflow.
• Chronic bronchitis involves inflamed airways due to irritants like cigarette smoke.
• Emphysema involves loss of lung function due to damage to air sacs.
• Asthma is an inflammatory disease of the bronchial tubes often triggered by allergens.
• Bronchospasms are contractions of smooth muscle, restricting airflow.
• Airway inflammation causes swelling and mucus buildup.

Pathology of the Respiratory System (Specific Conditions)

• Upper respiratory infections (URI) and acute nasopharyngitis are common cold conditions.
• Allergic rhinitis is an allergic reaction to airborne allergens.
• Epistaxis is a nosebleed.
• Sinusitis is an inflammation of the sinuses.
• Pharyngitis is inflammation of the pharynx (sore throat).
• Laryngitis is an inflammation of the larynx.
• Bronchiectasis is permanent dilation of the bronchi due to infection or inflammation.
• Pleural effusion is excess fluid accumulation in the pleural cavity.
• Pyothorax (empyema) is pus in the pleural cavity.
• Hemothorax is blood in the pleural cavity.
• Pneumothorax is air in the pleural cavity, collapsing the lungs.
• Pneumonia is inflammation of the lungs with fluid.
• Eupnea is normal breathing.
• Apnea is absence of breathing.
• Bradypnea is slow breathing.
• Tachypnea is rapid breathing.
• Dyspnea is shortness of breath.

Additional Procedures and Conditions

• Expectoration is coughing up and spitting out fluids.
• Hemoptysis is coughing up blood.
• Anoxia is lack of oxygen in tissues.
• Hypoxia is reduced oxygen in tissues.
• Cyanosis is bluish skin discoloration due to low oxygen.
• Bronchoscopy and laryngoscopy are procedures for visualizing the airway structures, while bronchoscopy visualizes the airways, and laryngoscopy visualizes the larynx and vocal cords.