Chapter 23 Respiratory System Outline

Chapter 23 Respiratory System Outline Chapter 23 Respiratory System Outline I Importance of Respiration The respiratory system is essential for life providing the body with oxygen and eliminating carbon dioxide Overview of Respiratory System Functions Gas exchange The primary function involving the uptake of oxygen and release of carbon dioxide Regulation of blood pH The respiratory system plays a vital role in maintaining acidbase balance by controlling carbon dioxide levels Vocalization Air passage through the larynx allows for speech production Protection The respiratory system acts as a barrier against inhaled pathogens and irritants Divisions of the Respiratory System Upper Respiratory Tract Includes the nose pharynx and larynx Lower Respiratory Tract Includes the trachea bronchi bronchioles and alveoli II Upper Respiratory Tract Nose External nose The visible portion made of cartilage and bone Nasal cavity The internal space lined with mucous membrane containing olfactory receptors Functions Warms filters and humidifies inhaled air Houses olfactory receptors for smell Serves as a resonating chamber for speech Pharynx Location The throat connecting the nasal cavity and mouth to the larynx and esophagus Regions Nasopharynx Behind the nasal cavity houses the pharyngeal tonsils adenoids Oropharynx Behind the oral cavity contains the palatine and lingual tonsils Laryngopharynx The lowest portion connecting to the larynx and esophagus Functions Passageway for air and food as well as sound production Larynx Location The voice box located at the top of the trachea 2 Composed of nine cartilages including the thyroid cartilage Adams apple Functions Protects the trachea from foreign objects Produces sound through the vocal cords Vocal cords Two folds of mucous membrane that vibrate to create sound III Lower Respiratory Tract Trachea Location The windpipe extending from the larynx to the bronchi Composed of Cshaped cartilage rings that keep it open Function Passageway for air to the lungs Bronchi Location Two branches that divide from the trachea leading to each lung Similar to the trachea but with smaller cartilage rings Function Conducts air to each lung Bronchioles Location Smaller branches that divide from the bronchi Lack cartilage supported by smooth muscle Function Regulate airflow to the alveoli Alveoli Location Tiny air sacs at the ends of bronchioles Thinwalled and surrounded by capillaries Function The primary site of gas exchange between air and blood Respiratory Membrane The thin barrier between the air in the alveoli and the blood in the capillaries consisting of the alveolar epithelium capillary endothelium and their basement membranes Function Facilitates the rapid diffusion of oxygen and carbon dioxide IV Mechanics of Breathing Inspiration The process of taking in air involving the contraction of the diaphragm and external intercostal muscles Diaphragm A domeshaped muscle that contracts and flattens increasing thoracic volume External intercostal muscles Contraction pulls the rib cage upwards and outwards further expanding the chest cavity Expiration The process of exhaling air involving the relaxation of the diaphragm and external intercostal muscles and potentially the contraction of the internal intercostal muscles 3 Passive expiration Relaxation of the muscles allows the lungs to recoil and air to be passively expelled Active expiration During forceful exhalation the internal intercostal muscles contract pulling the rib cage downwards and inwards decreasing thoracic volume Lung Volumes and Capacities Tidal volume TV The volume of air inhaled or exhaled in a normal breath Inspiratory reserve volume IRV The additional volume of air that can be inhaled after a normal inhalation Expiratory reserve volume ERV The additional volume of air that can be exhaled after a normal exhalation Residual volume RV The volume of air remaining in the lungs after a maximal exhalation Vital capacity VC The total volume of air that can be exhaled after a maximal inhalation TV IRV ERV Total lung capacity TLC The total volume of air that the lungs can hold VC RV V Gas Exchange Partial Pressures The pressure exerted by a specific gas in a mixture Diffusion The movement of molecules from an area of high concentration to an area of low concentration Oxygen Transport Dissolved in plasma A small amount of oxygen is dissolved directly in the blood plasma Bound to hemoglobin The majority of oxygen is transported bound to hemoglobin in red blood cells Carbon Dioxide Transport Dissolved in plasma A small amount of carbon dioxide is dissolved directly in the blood plasma Bound to hemoglobin A small amount of carbon dioxide binds to hemoglobin but at different sites than oxygen As bicarbonate ions The majority of carbon dioxide is transported in the blood as bicarbonate ions HCO3 formed through a series of reactions in red blood cells VI Regulation of Respiration Respiratory Centers Located in the brainstem these centers control the rate and depth of breathing Medullary Respiratory Center The primary respiratory center responsible for generating the basic rhythm of breathing Pontine Respiratory Centers Finetune breathing patterns and help coordinate inspiration and 4 expiration Chemoreceptors Specialized sensory neurons that detect changes in blood gases oxygen carbon dioxide and pH Central chemoreceptors Located in the brainstem sensitive to changes in carbon dioxide levels and pH in the cerebrospinal fluid Peripheral chemoreceptors Located in the carotid and aortic bodies sensitive to changes in oxygen carbon dioxide and pH in the blood Factors Influencing Respiration Carbon dioxide levels Increased CO2 levels stimulate breathing to expel excess CO2 Oxygen levels Decreased oxygen levels stimulate breathing to increase oxygen intake pH Changes in blood pH can also affect breathing rate and depth Other factors Exercise emotions and pain can also influence respiration VII Respiratory Disorders Upper respiratory tract infections URTIs Common colds flu sinusitis and pharyngitis Lower respiratory tract infections LRTIs Bronchitis pneumonia and tuberculosis Asthma A chronic inflammatory disease of the airways characterized by bronchospasm and airway narrowing Chronic obstructive pulmonary disease COPD A group of diseases that block airflow and make it difficult to breathe including chronic bronchitis and emphysema Lung cancer A leading cause of death worldwide often linked to smoking Pneumothorax A collapsed lung caused by air leaking into the space between the lung and the chest wall VIII Clinical Applications Spirometry A test that measures lung function to diagnose and monitor respiratory disorders Pulse oximetry A noninvasive technique that measures the oxygen saturation of the blood Arterial blood gas analysis A test that measures the levels of oxygen carbon dioxide and pH in the blood Bronchoscopy A procedure that uses a flexible tube with a camera to visualize the airways Chest Xray A common imaging technique used to diagnose lung conditions IX Summary The respiratory system is a vital organ system responsible for gas exchange pH regulation vocalization and protection It includes the upper respiratory tract nose pharynx and larynx and the lower respiratory tract trachea bronchi bronchioles and alveoli The mechanics of breathing involve inspiration and expiration which are controlled by respiratory 5 centers in the brainstem Gas exchange occurs in the alveoli where oxygen enters the blood and carbon dioxide exits Respiratory disorders can affect the function of the respiratory system leading to a variety of symptoms Understanding the structure and function of the respiratory system is crucial for healthcare professionals in diagnosing treating and preventing respiratory illnesses