Respiratory System
- Introduction
• The respiratory system is responsible for breathing (respiration), including the exchange of oxygen and carbon dioxide between the body and environment.
• It helps maintain oxygen supply to body cells and removes carbon dioxide, a metabolic waste.
• It also assists in voice production, olfaction (smell), and acid-base balance. - Components of the Respiratory System
A. Upper Respiratory Tract
• Nose and nasal cavity
• Paranasal sinuses
• Pharynx (nasopharynx, oropharynx, laryngopharynx)
• Larynx (voice box)
B. Lower Respiratory Tract
• Trachea (windpipe)
• Bronchi and bronchioles
• Lungs (including alveoli) - Structure and Function of Major Parts
A. Nose and Nasal Cavity
• Main entrance for air;
• Filters, warms, and moistens inhaled air.
• Contains olfactory receptors for smell.
• Paranasal sinuses reduce skull weight and resonate voice.
B. Pharynx
• Muscular tube connecting nasal and oral cavities to larynx and esophagus.
• Acts as a passageway for air and food.
• Divided into nasopharynx, oropharynx, and laryngopharynx.
C. Larynx
• Connects pharynx to trachea.
• Contains vocal cords for sound production.
• Prevents food from entering the lower respiratory tract via the epiglottis.
D. Trachea
• Rigid tube supported by cartilage rings.
• Conducts air to bronchi.
• Lined with ciliated mucosa to trap and remove debris.
E. Bronchi and Bronchioles
• Bronchi branch from trachea into each lung.
• Bronchi further divide into smaller bronchioles.
• Bronchioles end in alveolar sacs.
F. Lungs and Alveoli
• The lungs are paired organs where gas exchange occurs.
• Alveoli are tiny air sacs with thin walls surrounded by capillaries.
• Site of oxygen and carbon dioxide exchange via diffusion. - Mechanism of Breathing (Ventilation)
A. Inspiration (Inhalation)
• Diaphragm contracts and moves downward.
• External intercostal muscles contract, expanding the rib cage.
• Thoracic cavity volume increases, pressure decreases.
• Air flows into lungs.
B. Expiration (Exhalation)
• Diaphragm and intercostal muscles relax.
• Thoracic cavity volume decreases, pressure increases.
• Air flows out of lungs. - Gas Exchange
A. External Respiration
• Exchange of oxygen and carbon dioxide between alveoli and blood in pulmonary capillaries.
B. Internal Respiration
• Exchange of gases between blood in systemic capillaries and body tissues. - Control of Respiration
A. Neural Control
• Respiratory center located in the medulla oblongata and pons.
• Controls rate and depth of breathing.
B. Chemical Control
• Chemoreceptors in carotid and aortic bodies monitor blood oxygen, carbon dioxide, and pH levels.
• High CO2 or low O2 levels stimulate increased breathing rate. - Lung Volumes and Capacities
• Tidal Volume (TV): air in normal breath (~500 ml).
• Inspiratory Reserve Volume (IRV): extra air inhaled forcibly.
• Expiratory Reserve Volume (ERV): extra air exhaled forcibly.
• Residual Volume (RV): air remaining after forced exhalation.
• Vital Capacity (VC): TV + IRV + ERV.
• Total Lung Capacity (TLC): VC + RV. - Respiratory Disorders Commonly Seen in Nursing Practice
• Asthma: chronic airway inflammation and bronchoconstriction.
• Chronic Obstructive Pulmonary Disease (COPD): includes emphysema and chronic bronchitis.
• Pneumonia: infection of lungs causing inflammation and fluid buildup.
• Tuberculosis: bacterial infection affecting lungs.
• Pulmonary edema: fluid accumulation in alveoli.
• Emphysema: destruction of alveoli reducing gas exchange.
• Bronchitis: inflammation of bronchi.
• Pneumothorax: air in pleural space causing lung collapse. - Nursing Care and Considerations
• Monitor respiratory rate, rhythm, and depth.
• Administer oxygen therapy as prescribed.
• Encourage deep breathing and coughing exercises.
• Assist with sputum collection and airway clearance.
• Educate patients about smoking cessation and avoiding pollutants.
• Recognize respiratory distress symptoms early (cyanosis, dyspnea, use of accessory muscles).
• Manage medications like bronchodilators, corticosteroids, and antibiotics. - Summary for Quick Review
The respiratory system facilitates oxygen delivery to the blood and removes carbon dioxide through structures including the nose, pharynx, larynx, trachea, bronchi, and lungs. Breathing involves the coordinated contraction and relaxation of respiratory muscles, regulated by neural and chemical signals. Gas exchange occurs at alveoli, where oxygen enters and carbon dioxide exits the bloodstream. Lung volumes and capacities quantify respiratory function. Nursing care focuses on monitoring respiratory status, supporting breathing, preventing complications, and educating patients.