Chapter 17 Respiratory System PDF

Respiratory System Chapter 17  Learning Objectives Lesson 17.1: Anatomy of the Respiratory System and Respiratory Conditions 1. List the major organs of the respiratory system and describe the function of each organ in relation to the major functions of the...

Respiratory System Chapter 17  Learning Objectives Lesson 17.1: Anatomy of the Respiratory System and Respiratory Conditions 1. List the major organs of the respiratory system and describe the function of each organ in relation to the major functions of the respiratory system. 2. Discuss the structures included in the upper respiratory tract, as well as identify and describe the major conditions of the upper respiratory tract. 3. Discuss the structures included in the lower respiratory tract, as well as identify and describe the major conditions of the lower respiratory tract.  Structural Plan  Basic plan of respiratory system would be similar to an inverted tree if it were hollow; leaves of the tree would be comparable to alveoli, with the microscopic sacs enclosed by networks of capillaries  Diffusion is the mode for gas exchange that occurs in the respiratory mechanism Structural Plan of Respiratory Organs  Respiratory Tracts  Upper respiratory tract  Nose  Pharynx  Larynx  Lower respiratory tract  Trachea  Bronchial tree  Lungs  Respiratory Mucosa  Mucous membrane that lines the air distribution tubes in the respiratory tree  More than 125 mL of mucus produced each day forms a “mucus blanket” over much of the respiratory mucosa  Mucus serves as an air purification mechanism by trapping inspired irritants such as dust and pollen  Cilia on mucosal cells beat in only one direction, moving mucus upward to pharynx for removal Respiratory Mucosa Lining the Trachea  Nose  Structure  Nasal septum separates interior of nose into two cavities  Mucous membrane lines nose  Nasal polyps: Noncancerous growths that project from nasal mucosa (associated with chronic hay fever)  Frontal, maxillary, sphenoidal, and ethmoidal sinuses drain into nose The Paranasal Sinuses  Functions of the Nose  Warms and moistens inhaled air  Contains sense organs of smell  Structure of the Pharynx (1 of 2)  Pharynx (throat) is about 12.5 cm (5 inches) long  Divided into nasopharynx, oropharynx, and laryngopharynx  Two nasal cavities, mouth, esophagus, larynx, and auditory tubes all have openings into pharynx  Structure of the Pharynx (2 of 2)  Pharyngeal tonsils and openings of auditory tubes open into nasopharynx; other tonsils found in oropharynx  Mucous membrane lines pharynx Head and Neck  Functions of the Pharynx  Passageway for food and liquids  Air distribution; passageway for air  Tonsils: Masses of lymphoid tissue embedded in pharynx provide immune protection Tonsillitis  Structure of the Larynx  Located just below pharynx; also referred to as the voice box  Several pieces of cartilage form framework  Thyroid cartilage (Adam’s apple) is largest  Epiglottis partially covers opening into larynx  Mucous lining  Vocal cords stretch across interior of larynx; space between cords is the glottis The Larynx C from Cox JD: Radiation oncology, ed 9, Philadelphia, 2010, Mosby  Functions of the Larynx  Air distribution; passageway for air to move to and from lungs  Voice production  Laryngeal Cancer  Incidence increases with age and alcohol abuse  Occurs most often in men over age 50  If larynx removed, “esophageal speech” or electric artificial larynx needed for speech  Upper Respiratory Infections (URIs)  Rhinitis: Nasal inflammation, as in a cold, influenza, or allergy  Infectious rhinitis—common cold  Allergic rhinitis—hay fever  Pharyngitis (sore throat): Inflammation or infection of the pharynx  Laryngitis  Inflammation of the larynx resulting from infection or irritation  Epiglottitis: Life-threatening condition caused by Haemophilus influenzae type B (Hib) infection  Croup: Non–life-threatening type of laryngitis caused by parainfluenza viruses producing a barking cough  Anatomical Conditions  Deviated septum: Septum that is abnormally far from the midsagittal plane (congenital or acquired)  Epistaxis (bloody nose) can result from mechanical injuries to the nose, hypertension, or other factors  Trachea  Structure  Tube (windpipe) about 11 cm (4.5 inches) long that extends from larynx into the thoracic cavity  Mucous lining  C-shaped rings of cartilage hold trachea open  Function: Passageway for air to move to and from lungs Structure of the Trachea  Obstruction of the Trachea  Blockage of trachea occludes the airway, and if complete, causes death in minutes  Tracheal obstruction causes more than 4000 deaths annually in the United States  Abdominal thrust maneuver is a lifesaving technique used to free the trachea of obstructions; also called abdominal thrusts  Tracheostomy—surgical procedure in which a tube is inserted into an incision  Structure of the Bronchi, Bronchioles, and Alveoli  Trachea branches into right and left bronchi  Right primary bronchus more vertical than left  Aspirated objects most often lodge in right primary bronchus or right lung  Each bronchus branches into smaller and smaller tubes (secondary bronchi), eventually leading to bronchioles  Bronchioles end in clusters of microscopic alveolar sacs, the walls of which are made up of alveoli Bronchioles and Alveoli Network Graphics  Functions of Bronchi, Bronchioles, and Alveoli  Bronchi and bronchioles: Air distribution; passageway for air to move to and from alveoli  Alveoli: Exchange of gases between air and blood  Type II cells produce surfactant to help reduce surface tension or "stickiness" Gas-Exchange Structures of the Lung  Respiratory Distress  Relative inability to inflate the alveoli  Infant respiratory distress syndrome (IRDS): Leading cause of death in premature infants, resulting from lack of surfactant production in alveoli  Adult respiratory distress syndrome (ARDS): Impairment of surfactant by inhalation of foreign substances or other conditions  Structure of the Lungs  Size: Large enough to fill the chest cavity, except for middle space occupied by heart and large blood vessels  Apex: Narrow upper part of each lung, under collarbone  Base: Broad lower part of each lung; rests on diaphragm Lungs  Structure of the Pleura  Moist, smooth, slippery membrane that lines chest cavity and covers outer surface of lungs; reduces friction between the lungs and chest wall during breathing Lungs and Pleura (1 of 2)  Lungs and Pleura (2 of 2)  Function: Breathing (pulmonary ventilation)  Pleurisy: Inflammation of the pleura  Atelectasis: Incomplete expansion or collapse of the lung (alveoli); can be caused by:  Pneumothorax: Presence of air in the pleural space  Hemothorax: Presence of blood in the pleural space Pneumothorax  Conditions of the Lower Respiratory Tract  Acute bronchitis  Pneumonia  Tuberculosis  Restrictive pulmonary disorders  Obstructive pulmonary disorders  COPD  Chronic bronchitis  Emphysema  Asthma  Lung cancer  Learning Objectives Lesson 17.2: Respiration and Gas Exchange 4. Discuss respiration and pulmonary ventilation, including the mechanics of breathing and pulmonary volumes. 5. Describe the regulation of ventilation and identify breathing patterns. 6. Compare, contrast, and explain the mechanism responsible for the exchange of gases that occurs during external and internal respiration. 7. Describe the transport of gases by blood.  Respiration  Mechanics of breathing  Pulmonary ventilation includes two phases called inspiration (movement of air into lungs) and expiration (movement of air out of lungs)  Changes in size and shape of thorax cause changes in air pressure within that cavity and in the lungs because as volume changes, pressure changes in the opposite direction  Air moves into or out of lungs because of pressure differences (pressure gradient); air moves from high air pressure toward low air pressure Overview of Respiration Mechanics of Breathing  Inspiration  Active process: Muscles increase volume of thorax, decreasing lung pressure, which causes air to move from atmosphere into lungs (down the pressure gradient)  Inspiratory muscles include diaphragm and external intercostals  Diaphragm flattens during inspiration: Increases top-to-bottom length of thorax  External intercostals: Contraction elevates the ribs and increases the size of the thorax from front to back and from side to side  Expiration (1 of 2)  Reduction in the size of the thoracic cavity decreases its volume and thus increases its pressure, so air moves down the pressure gradient and leaves the lungs  Quiet expiration ordinarily a passive process  During expiration, thorax returns to its resting size and shape  Elastic recoil of lung tissues aids in expiration  Expiration (2 of 2)  Expiratory muscles used in forceful expiration are internal intercostals and abdominal muscles  Internal intercostals: Contraction depresses the rib cage and decreases the size of the thorax from front to back  Abdominal muscles: Contraction elevates the diaphragm, thus decreasing size of the thoracic cavity from top to bottom  Volumes of Air Exchanged in Pulmonary Ventilation (1 of 2)  Volumes of air exchanged in breathing can be measured with a spirometer  Tidal volume (TV): Amount normally breathed in or out with each breath  Vital capacity (VC): Largest amount of air that one can breathe out in one expiration  Expiratory reserve volume (ERV): Amount of air that can be forcibly exhaled after expiring the tidal volume  Volumes of Air Exchanged in Pulmonary Ventilation (2 of 2)  Inspiratory reserve volume (IRV): Amount of air that can be forcibly inhaled after a normal inspiration  Residual volume (RV): Air that remains in the lungs after the most forceful expiration Pulmonary Ventilation Volumes  Regulation of Ventilation  Regulation of ventilation permits the body to adjust to varying demands for oxygen supply and carbon dioxide removal  Brainstem: Central regulatory centers are called respiratory control centers (inspiratory and expiratory centers)  Medullary centers: Under resting conditions the medullary rhythmicity area produces a normal rate and depth of respirations (12 to 18 per minute)  Central Regulatory Centers  Pontine centers: As conditions in the body vary, these centers in the pons can alter the activity of the medullary rhythmicity area, thus adjusting breathing rhythm  Brainstem centers are influenced by information from other parts of the brain and from sensory receptors located in other body areas  Regulation of Respiration (1 of 2)  Cerebral cortex: Voluntary (but limited) control of respiratory activity  Receptors influencing respiration  Chemoreceptors: Respond to changes in carbon dioxide, oxygen, and blood acid levels; located in carotid and aortic bodies  Pulmonary stretch receptors: Respond to the stretch in lungs, thus protecting respiratory organs from overinflation Regulation of Respiration (2 of 2)  Breathing Patterns (1 of 2)  Eupnea: Normal breathing  Hyperventilation: Rapid and deep respirations  Hypoventilation: Slow and shallow respirations  Dyspnea: Labored or difficult respirations  Orthopnea: Dyspnea relieved by moving into an upright or sitting position  Breathing Patterns (2 of 2)  Apnea: Stopped respiration  Cheyne-Stokes respiration (CSR): Cycles of alternating apnea and hyperventilation associated with critical conditions  Respiratory arrest: Failure to resume breathing after a period of apnea Gas Exchange and Transport and Gas Exchange  Pulmonary Gas Exchange  Carbaminohemoglobin breaks down into carbon dioxide and hemoglobin  Carbon dioxide moves out of lung capillary blood into alveolar air and out of body in expired air  Oxygen moves from alveoli into lung capillaries  Hemoglobin combines with oxygen, producing oxyhemoglobin  Blood Transportation of Gases (1 of 2)  Oxyhemoglobin breaks down into oxygen and hemoglobin  Oxygen moves out of tissue capillary blood into tissue cells  Carbon dioxide moves from tissue cells into tissue capillary blood  Hemoglobin combines with carbon dioxide, forming carbaminohemoglobin  Blood Transportation of Gases (2 of 2)  Transport of oxygen  Only small amounts of oxygen (O2) can be dissolved in blood  Most oxygen combines with hemoglobin to form oxyhemoglobin (HbO2) to be carried in blood  Transport of carbon dioxide  Dissolved carbon dioxide (CO2): 10%  Carbaminohemoglobin (HbCO2): 20%  Bicarbonate ions (HCO3−): 70% Questions?