Introduction to the Respiratory System

Introduction

• The respiratory system facilitates gas exchange, taking in oxygen and releasing carbon dioxide.
• This process is vital for cellular respiration, powering bodily functions.

Components of the Respiratory System

• Nasal Cavity: Warms, humidifies, and filters inhaled air. Hairs and mucus trap particles.
• Pharynx (Throat): A passageway for air and food.
• Larynx (Voice Box): Houses vocal cords, producing sound.
• Trachea (Windpipe): A rigid tube carrying air. C-shaped cartilage rings prevent collapse.
• Bronchi: Two branches leading to the lungs.
• Bronchioles: Smaller subdivisions of the bronchi.
• Alveoli: Tiny air sacs in the lungs, sites of gas exchange. Surrounded by capillaries.

Process of Respiration

• Inhalation (Inspiration): The diaphragm contracts, flattening and expanding the thoracic cavity. External intercostal muscles elevate ribs, further expanding the cavity and reducing pressure, drawing air into the lungs.
• Exhalation (Expiration): The diaphragm relaxes, returning to its dome shape. The rib cage descends, decreasing thoracic cavity volume and increasing pressure, forcing air out of the lungs.

Gas Exchange

• Diffusion: Oxygen diffuses from alveoli into capillaries; carbon dioxide diffuses from capillaries into alveoli.
• Pressure Differences: Higher oxygen pressure in alveoli drives oxygen into blood. Conversely, higher carbon dioxide pressure in blood drives it into alveoli.

Control of Respiration

• Medulla Oblongata: Contains respiratory rhythmicity centers, controlling breathing rate and depth.
• Chemoreceptors: Detect changes in blood oxygen, carbon dioxide, and pH levels, influencing the medulla.
• Peripheral Chemoreceptors: Located in carotid and aortic bodies, monitoring blood gas levels and pH, signaling respiratory centers.

Lung Volumes and Capacities

• Tidal Volume: Air inhaled or exhaled during a normal breath.
• Inspiratory Reserve Volume: Air inhaled beyond a normal breath.
• Expiratory Reserve Volume: Air exhaled beyond a normal breath.
• Residual Volume: Air remaining in lungs after maximal exhalation.
• Inspiratory Capacity: Tidal volume plus inspiratory reserve volume.
• Functional Residual Capacity: Expiratory reserve volume plus residual volume.
• Vital Capacity: Maximum air moved in and out of lungs in a single breath.
• Total Lung Capacity: Sum of all lung volumes.

Disorders of the Respiratory System

• Asthma: Chronic inflammatory disorder causing airway constriction, reducing airflow.
• COPD (Chronic Obstructive Pulmonary Disease): Progressive lung diseases (emphysema, chronic bronchitis), hindering breathing.
• Pneumonia: Lung inflammation, often infection-related.
• Tuberculosis (TB): Infectious disease affecting the lungs.
• Cystic Fibrosis: Genetic disorder affecting mucus production, increasing susceptibility to respiratory infections.

Factors Affecting Respiration

• Exercise: Increases oxygen demand, leading to increased respiratory rate and depth.
• Altitude: Lower oxygen levels at high altitudes increase breathing to compensate.
• Disease: Many diseases impact respiratory function.
• Age: Respiratory function typically declines with age, reduced lung elasticity affecting gas exchange.

This quiz covers the essential components and functions of the respiratory system. Understand the processes of gas exchange, including the roles of various organs such as the nasal cavity, larynx, and alveoli. Test your knowledge on how respiration supports cellular functions and energy production.