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Unformatted text preview: PowerLecture: Chapter 40 Respiration Section 40.0: Weblinks and InfoTrac See the latest Weblinks and InfoTrac articles for this chapter online Videos: CNN Ask your Thomson Sales Representative for these volumes on CD or VHS Environmental Science, 2002, Vol. 5, Antismoking Campaign (2:13) Impacts, Issues: Up In Smoke In the US, about 3,000 teenagers take up smoking every day Just one cigarette immobilizes cilia that line airways of the lungs for hours, preventing them from sweeping away airborne pathogens and pollutants Impacts, Issues: Up In Smoke Filmy gunk from pathogens promotes: asthma attacks bronchitis colds Nicotine: constricts blood vessels raises blood pressure makes blood stickier and clots more likely Costs of smoking: clogged arteries heart attacks strokes Impacts, Issues: Up In Smoke Smoking increases the risk of deadly lung cancers Secondhand smoke causes about 3,000 lung cancer deaths each year Impacts, Issues Video Section 40.1: Weblinks and InfoTrac See the latest Weblinks and InfoTrac articles for this chapter online Respiration Physiological process by which oxygen moves into internal environment and carbon dioxide moves out Oxygen is needed for aerobic respiration Carbon dioxide is produced by same Respiratory System Acts in concert with the circulatory system to deliver oxygen and remove carbon dioxide Also helps regulate acid-base balance Pressure Gradients Concentration gradients for gases Gases diffuse down their pressure gradients Gases enter and leave the body by diffusing down pressure gradients across respiratory membranes Atmospheric Pressure Pressure exerted by the weight of the air on objects on Earth’s surface At sea level = 760 mm Hg Oxygen is 21% of air; its partial pressure is about 160 mm Hg Fick’s Law Describes the rate at which a substance (such as oxygen) will diffuse across a membrane (such as a respiratory surface) Rate is proportional to the pressure gradient across the membrane and to the surface area of the membrane Surface-to-Volume Ratio As animal size increases, surface-to-volume ratio decreases Small, flattened animals can use the body surface as their respiratory surface Larger animals have special structures to increase respiratory surface, such as gills or lungs Section 40.2: Weblinks and InfoTrac See the latest Weblinks and InfoTrac articles for this chapter online Invertebrate Respiration Integumentary exchange Gills Internal respiratory surfaces Book lungs Tracheal system Invertebrate Respiration Examples of respiratory surfaces Section 40.3: Weblinks and InfoTrac See the latest Weblinks and InfoTrac articles for this chapter online Fish Gills Most commonly internal Water is drawn in through mouth and passed over gills Fish Gills Bony fish respiration Countercurrent Flow Blood flow runs in the opposite direction of water flow over the filaments This enhances movement of oxygen from water to blood Frog Respiration Force air into their lungs by elevating floor of mouth Frog Respiration Frog respiration Vertebrate Lungs Originated in some fishes as outpouching from gut wall Allow gas exchange in oxygen-poor aquatic habitats and on land Vertebrate Lungs Vertebrate lungs Salamander Gills Avian Respiration Lungs are inelastic and connect to a series of air sacs Air is drawn continually though each lung Avian Respiration Bird respiration Section 40.4: Weblinks and InfoTrac See the latest Weblinks and InfoTrac articles for this chapter online Human Respiratory System Human Respiratory System Human respiratory system Speech Production Vocal cords stretch across laryngeal opening; opening between them is glottis Position of cords is varied to create different sounds Speech Production Vocal cords Section 40.5: Weblinks and InfoTrac See the latest Weblinks and InfoTrac articles for this chapter online Cutaway View of Alveolus Alveolus Structure of an alveolus Respiratory Membrane Area between an alveolus and a pulmonary capillary Oxygen and carbon dioxide diffuse across easily Oxygen Transport Most oxygen is carried bound to hemoglobin in red blood cells Hemoglobin has a great affinity for oxygen when it is at high partial pressure (in pulmonary capillaries) Lower affinity for oxygen in tissues, where partial pressure is low Oxygen Transport Globin and hemoglobin structure Bicarbonate Formation Partial Pressure Gradients Partial pressure gradients Section 40.6: Weblinks and InfoTrac See the latest Weblinks and InfoTrac articles for this chapter online Breathing Moves air into and out of lungs Occurs in a cyclic pattern called the respiratory cycle One respiratory cycle consists of inhalation and exhalation Inhalation Diaphragm flattens External intercostal muscles contract Volume of thoracic cavity increases Lungs expand Air flows down pressure gradient into lungs Normal (Passive) Exhalation Muscles of inhalation relax Thoracic cavity recoils Lung volume decreases Air flows down pressure gradient and out of lungs Respiratory Cycle Respiratory cycle Active Exhalation Muscles in the abdomen and the internal intercostal muscles contract This decreases thoracic cavity volume more than passive exhalation A greater volume of air must flow out to equalize intrapulmonary pressure with atmospheric pressure Changes in Pressure Changes in Pressure Pressure-gradient changes during respiration Respiratory Volumes Respiratory Volumes Changes in lung volume and pressure Section 40.7: Weblinks and InfoTrac See the latest Weblinks and InfoTrac articles for this chapter online Control of Breathing Medulla oblongata sets main rhythm; centers in pons fine-tune it Magnitude of breathing depends on concentration of oxygen and H+ Brain detects H+, increases breathing Carotid bodies and aortic bodies detect drop in oxygen, increase breathing Section 40.8: Weblinks and InfoTrac See the latest Weblinks and InfoTrac articles for this chapter online Bronchitis Irritation of the ciliated epithelium that lines the bronchiole walls Air pollutants, smoking, or allergies can be the cause Excess mucus causes coughing, can harbor bacteria Chronic bronchitis scars and constricts airways Emphysema An irreversible breakdown in alveolar walls Lungs become inelastic May be caused by a genetic defect Most often caused by smoking Effects of Smoking Shortened life expectancy Increased rates of cancers Increased rate of heart disease Impaired immune function and healing Detrimental to fetus Section 40.9: Weblinks and InfoTrac See the latest Weblinks and InfoTrac articles for this chapter online Humans at High Altitude Permanent residents of high areas have More vascularized lungs Larger ventricles in heart More mitochondria in muscle Acclimatization Changes in rate of breathing, heart output Kidney secretes erythropoietin; red cell production increases Carbon Monoxide (CO) Colorless, odorless gas Competes with oxygen for binding sites in hemoglobin Binding capacity is at least 200 times greater than oxygen’s Exposure impairs oxygen delivery The Bends Pressure increases with depth Increases N2 dissolved in blood Can bubble out if diver ascends too fast Pain in joints, impaired vision, paralysis Diving Mammals Marine mammals have special physiological and behavioral adaptations Blood is directed preferentially to heart and central nervous system Gliding conserves energy Heimlich Maneuver Heimlich maneuver ...
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