Summary Chapter 10 Respiration Takes Place Throughout the Body Breathing ventilation moving air in and out of lungs External Respiration gas exchange between air and blood in the lings Internal Respiration gas exchange between blood and tissues Cellular Respiration oxygen use to produce ATP carbon dioxide as waste Respiratory System Consists of Upper and Lower Respiratory Tract Upper Respiratory Tract Nose nasal passages Lower Respiratory Tract Bronchi and bronchioles Pharynx Larynx Trachea Lungs Alveoli Upper Respiratory Tract Functions Acts as passageway for respiration Has receptors for smell entrapped in mucus Moistens and warms incoming air Has resonating chambers for voice Lower Respiratory Tract Funtions Larynx Maintains an open airway Routes food and air appropriately Filters larger foreign material from incoming air inhaled microorganisms are Cilia push microorganisms and mucus up and out of respiratory tract Smoking Damages cilia impairs this defense Assists in sound production Trachea transports air to and from lungs Bronchi branch into lungs Lungs transport air to alveoli for gas exchange Defenses of the Respiratory Tract Mucus entraps microorganisms Smokers cough Cough reflex The Lungs Are Organs of Gas Exchange Located within thoracic cavity Surrounded by pleural membranes Bronchioles terminate in clusters of alveoli Alveoli Tiny air filled sacs Gas exchange occurs here Pulmonary capillaries in alveolar walls bring blood and air into close contact The Process of Breathing Involves a Pressure Gradient Inspiration expiration air in air out cycle Diaphragm and intercostal muscles relaxed Relaxed state Inspiration inhale Diaphragm contracts pulling muscle down intercostal muscles contract elevating chest wall and expanding volume of chest lowering pressure in lungs pulling in air Expiration exhale Muscles relax diaphragm resumes dome shape intercostal muscles allow chest to lower resulting in increase of pressure in chest and expulsion of air Lung Volumes and Vital Capacity Measure Lung Function Tidal Volume Volume of air inhaled and exhaled in a single breath Volume of air that remains in the airways and does not participate in gas Dead space volume exchange Vital Capacity Inspiratory reserve volume Expiratory reserve volume Residual volume Measured by spirometer Maximal volume that can be exhaled after maximal inhalation Lung Volumes and Vital Capacity Measure Lung Function Volume of air that can be inhaled beyond the tidal volume Volume of air that can be forcibly exhaled beyond the tidal volume Volume of air remaining in the lungs even after a forceful maximal expiration Gas Exchange and Transport Occur Passively Partial Pressure Partial Pressure The pressure exerted by one particular gas in a mixture of gases Partial pressure of a gas is proportional to its percentage of the total gas Gas always diffuses down its partial pressure gradient from higher to lower composition partial pressure External Respiration Exchange of Gases Between Air and Blood O2 diffuses from alveoli PO2 104 mmHg into blood Po2 40 mmHg down its CO2 diffuses from blood PCO2 46 mmHg into alveoli PCO2 40 mmHg down partial pressure gradient its partial pressure gradient Internal Respiration The Exchange of Gases with Tissue Fluids O2 diffuses down its pressure gradient from capillaries to interstitial fluid and then to cells CO2 diffuses down its pressure gradient from cells to interstitial fluid to capillaries Hemoglobin Transports Most O2 98 of O2 in blood is carried bound to hemoglobin molecules in red blood cells Hb O2 HbO2 hemoglobin oxygen oxyhemoglobin 2 of O2 is dissolved in plasma Most CO2 Is Transported in Plasma as Bicarbonate 70 of CO2 is converted to and transported in the plasma as bicarbonate 10 os CO2 is dissolved in plasma 20 of CO2 binds to hemoglobin for transport The Nervous System Regulates Breathing Respiratory centers are located in the medulla oblongata and the pons Establishes basin breathing pattern Neurons in medulla generate impulses every 4 5 seconds Stimulates intercostal muscles and diaphragm Chemical Receptors Monitor CO2 H and O2 levels Monitoring of CO2 levels Receptors in medulla oblongata monitor CO2 levels indirectly Receptors monitor H ions in cerebrospinal fluid PCO2 in arterial blood will cause in H in cerebrospinal fluid which will signal medulla oblongata to respiratory rate This is the primary regulator of respiration under normal conditions Monitoring PO2 Aortic and carotid bodies monitor PO2 Become activated if PO2 falls by at least 20 Will increase rate and depth of breathing in response to sufficiently lowered arterial PO2 The rate and depth of normal breathing is determined by the need to get rid of CO2 rather than the need to obtain O2 We Can Exert Some Conscious Control Conscious control resides in the cerebal cortex Able to modify breath to speak and sing Able to hold breath temporarily but cant override automatic controls located in medulla oblongata indefinitely Disorder of Respiratory System Reduced Air Flow or Gas Exchange Asthma spasmodic contraction of bronchi Cause by episodic allergic responses Controlled by bronchodilators and corticosteroids Emphysema alveoli permanently impaired Breathless due to decreased surface area for gas exchange Most cases result from smoking Bronchitis inflammation of bronchi May be acute or chronic Most cases related to smoking or air pollution Cystic Fibrosis an inherited condition Abnormally thick mucus in lungs impedes air flows Frequent pulmonary infections Other organ systems may be affected Disorders of Respiratory System Respiratory Infections and Intoxications Upper respiratory infections Colds and Flu Caused by viruses Antibiotics not effective Pneumonia infection of the lungs May be caused by bacteria or viruses One of the top 10 causes of death in the United States Treatment depends on cause Tuberculosis bacterial infection that scars the lungs later Diagnosis tuberculin skin test and chest X ray Treatment antibiotics Botulism poisoning by bacterial toxin Maybe active infection with symptoms or dormant infection that will reactivate Toxin consumed in improperly preserved foods Causes paralysis of skeletal muscles including intercostals and diaphragm Disorders of Respiratory System Lung Cancer Cancer uncontrolled growth of abnormal cells Impairs air flow gas exchange blood flow 1 3 of all U S Cancer deaths 90 of cases associated with smoking Causes Radon gas Workplace chemicals such as asbestos