Chapter 10 The Respiratory System Exchange of Gases http://www.encognitive.com/images/respiratory-system.jpg
Human Respiratory System UPPER RESPIRATORY TRACT LOWER RESPIRATORY TRACT Nose Passageway for air Mouth Passageway for food and air Epiglottis Covers larynx during swallowing Nasal cavity Filters, warms, and moistens air Pharynx (Throat) Common passageway for air, food, and liquid Larynx (Voice box) Production of sound Pleural membranes Cover the lungs and line the chest cavity Trachea (Windpipe) Main airway Lung Organ of gas exchange Intercostal muscle Moves ribs during respiration Bronchi Branching airways Alveoli Air sacs for gas exchange Rib Right lung Left lung Diaphragm Skeletal muscle of respiration Figure 10.1
Respiration Processes Breathing (ventilation): moving air in and out of lungs External respiration: gas exchange between air and blood Internal respiration: gas exchange between blood and tissues Cellular respiration: oxygen use to produce ATP, carbon dioxide as waste
The Upper Respiratory Tract Sinuses Nasal cavity External nose Opening of the auditory tube Nostril Pharynx Tongue Epiglottis Glottis Larynx Trachea Esophagus Figure 10.2
Upper Respiratory Tract Functions Passageway for respiration Receptors for smell Filters larger foreign material from incoming air Moistens and warms incoming air Resonating chambers for voice
The Lower Respiratory Tract Larynx Trachea Right bronchus Left bronchus Clusters of alveoli Bronchioles Figure 10.3
Lower Respiratory Tract Functions Larynx: maintains an open airway, routes food and air appropriately, assists in sound production Trachea: transports air to and from lungs Bronchi: branch into lungs Lungs: transport air to alveoli for gas exchange
Gas Exchange Between the Blood and Alveoli Figure 10.8a (1 of 3)
Gas Exchange Between the Blood and Alveoli Figure 10.8a (2 of 3) and (3 of 3)
Respiratory Cycle Figure 10.9
Breathing: Pressure Gradient Inspiration/expiration: air in/air out cycle 1. Relaxed state Diaphragm and intercostal muscles relaxed 2. Inspiration Diaphragm contracts, pulling muscle down; intercostal muscles contract, elevating chest wall and expanding volume of chest, lowering pressure in lungs, pulling in air 3. Expiration Muscles relax; diaphragm resumes dome shape; intercostal muscles allow chest to lower, resulting in increase of pressure in chest and expulsion of air
Measurement of Lung Capacity Figure 10.10a
Lung Volumes and Vital Capacity Tidal volume Volume of air inhaled and exhaled in a single breath Dead space volume Volume of air that remains in the airways and does not participate in gas exchange Vital capacity Maximal volume that can be exhaled after maximal inhalation
Lung Volumes and Vital Capacity Inspiratory reserve volume Volume of air that can be inhaled beyond the tidal volume Expiratory reserve volume Volume of air that can be forcibly exhaled beyond the tidal volume Residual volume Volume of air remaining in the lungs, even after a forceful maximal expiration Measured by spirometer
Gas Exchange and Transport: A Passive Process Gases diffuse according to their partial pressures External respiration: gases exchanged between air and blood Internal respiration: gases exchanged with tissue fluids Oxygen transport: bound to hemoglobin in red blood cells or dissolved in blood plasma Carbon dioxide transport: dissolved in blood plasma, bound to hemoglobin, or in the form of plasma bicarbonate
How O 2 and CO 2 are Transported in Blood Figure 10.12 (1 of 2)
How O 2 and CO 2 are Transported in Blood Figure 10.12 (2 of 2)
Regulation of Breathing: Nervous System Involvement Respiratory center in the medulla oblongata Establishes basic breathing pattern Chemical receptors Monitor carbon dioxide, hydrogen ions, and oxygen levels Medulla Sensitive to hydrogen ions in cerebrospinal fluid resulting from carbon dioxide in blood
Regulation of Breathing Figure 10.13
Regulation of Breathing: Nervous System Involvement Carotid and aortic bodies Sensitive to carbon dioxide, ph, and oxygen levels Conscious control Resides in higher brain centers Ability to modify breath
Disorders of Respiratory System Reduced air flow Asthma Spasmodic contraction of bronchial muscles Bronchial swelling Increased production of mucous Typically occurs as a result of exposure to an allergen Emphysema Destruction of connective tissue... Loss of elasticity Increased pressure damages the alveoli thereby reducing the overall surface area for gas exchange Bronchitis Inflammation of the bronchi Acute or chronic
Disorders of Respiratory System Infections Pneumonia Inflammation of lungs typically due to an infection Excess fluid secreted by alveoli impairs gas exchange Tuberculosis Caused by Mycobacterium tuberculosis Airborne Can leave scarring in the lungs Can become dormant and reactivate later Botulism Caused by Clostridium botulinum Toxin produced inhibits neurotransmitters thereby preventing the transmission of nerve signals respiratory failure
Disorders of Respiratory System Lung cancer Proliferation of abnormal cells that impede the function of normal cells Can obstruct airways but also impair the exchange of gases in the alveoli Congestive heart failure Heart begins to fail causing blood to back up in the pulmonary vessels The back up of blood increases the pressure in the capillaries associated with the alveoli causing fluid to leak from the capillaries Gas exchange is inhibited Cystic fibrosis Genetic condition in which mucous producing cells produces very thick, sticky mucous. Provides conditions for bacteria to grow allowing for chronic infections