Môn Sinh học - Chapter 42: Circulation and gas exchange

Circulation and Gas ExchangeChapter 42Chapter 42 Warm-UpHow does the heart beat?What are the 3 types of blood cells and their function?What is the function of the lymphatic system?List the pathway of one molecule of O2 from the air into your pinky toe.What you need to know:General characteristics of a respiratory surfaceHow O2 and CO2 are transported in bloodPathway of O2 from airRBCtissuesRespirationGas exchange supplies O2 for cellular respiration and disposes of CO2Partial pressure = pressure exerted by a particular gas in a mixture of gasesGases always diffuse from higher partial pressure  lower partial pressure© 2011 Pearson Education, Inc.Respiratory media: O2 in air or waterRespiratory surface: body wall, skin, gills, tracheae, lungsCharacteristics:MoistLarge surface area-to-volume ratioLarger animals: associated with vascular system© 2011 Pearson Education, Inc.Parapodium(functions as gill)(a) Marine worm(b) CrayfishGillsGillsTube foot(c) Sea starCoelomGills in aquatic animalsFish gills: absorb O2 through countercurrent exchange (blood flows opposite of water)Tracheal systems in insectsRespiratory system in birds (lungs + air sacs)Mammalian respiratory systemPathway of O2Nose/mouth: filtered, warmed, humidifiedPharynxLarynx: contains vocal cordsTrachea: windpipe; lined with cartilageBronchi: branches to lungsBronchiolesAlveoli: air sacs for gas exchangeMucus: traps particlesCilia: sweeps particles up to pharynxAlveoliFigure 42.30aExhaled airInhaled airPulmonaryarteriesSystemicveinsSystemicarteriesPulmonaryveinsAlveolarcapillariesAlveolarspacesAlveolarepithelialcellsHeartSystemiccapillariesCO2O2Body tissue(a) The path of respiratory gases in the circulatory systemCO2O281237645Diaphragm: dome-shaped muscle separating thoracic/abdominal cavitiesControl of Breathing in HumansControl center = medulla oblongataResponds to pH changes in bloodHigh CO2  carbonic acid forms  lowers pHSensors in the aorta and carotid arteries© 2011 Pearson Education, Inc.Adaptations for gas exchangeHemoglobin: respiratory pigment in vertebrates4 subunits, each with heme group with iron (Fe)Can carry 4 molecules of O2Bohr shift: O2 dissociates from hemoglobin when blood pH is lowArthropods, mollusks:blue hemocyanin pigmentcontains copper (Cu)© 2011 Pearson Education, Inc.How CO2 is transportedBicarbonate ions (70%)Hemoglobin (23%)Dissolved in plasma (7%)© 2011 Pearson Education, Inc.Respiratory Adaptations of Diving MammalsDiving mammals have evolutionary adaptations that allow them to perform extraordinary featsFor example, Weddell seals in Antarctica can remain underwater for 20 minutes to an hourFor example, elephant seals can dive to 1,500 m and remain underwater for 2 hoursHigh blood to body volume ratioStockpile O2 and deplete it slowlyStore oxygen in their muscles in myoglobin proteins© 2011 Pearson Education, Inc.Respiratory DisordersAsthma: airways constrictedBronchitis: bronchi swollen and cloggedPneumonia: inflammation of lung caused by infectionTuberculosis (TB): infectious disease caused by M. tuberculosisEmphysema: lose elasticity of lung tissueLung Cancer: abnormal cell growth in lungs