Principles of Animal PhysiologyRespiratory SystemRespiratory System▪Functions:IntroductionFunctions:▸ Provides O2▸Eliminates CO2▸Eliminates CO2▸ Regulates blood [H+] (pH)▸Phonation▸Phonation▸ Defends against microbes▸Remo es some chemicals as well as producing ▸Removes some chemicals as well as producing others▸Trap and dissolve blood clots▸Trap and dissolve blood clots▸ Temperature controlPrinciples of Animal PhysiologyRespiratory SystemRespiratory SystemIntroduction▪Atmospheric pressurePrinciples of Animal PhysiologyRespiratory SystemRespiratory SystemIntroduction▪ Composition of airPrinciples of Animal PhysiologyRespiratory SystemRespiratory SystemIntroduction▪ Diversity of gas exchange structuresPrinciples of Animal PhysiologyRespiratory SystemRespiratory SystemExternal & Internal Respiraton▪ External respiration can involve four major steps:▸ External bulk transport▸ Respiratory surface diffusion▸ Circulation▸ Tissue diffusionPrinciples of Animal PhysiologyRespiratory SystemRespiratory System▪It is more difficult to exchange gases in waterWater Breathers▪It is more difficult to exchange gases in water▸ O2relatively insoluble in water, 10k slower▸COis 20 times more soluble in water than O▸CO2is 20 times more soluble in water than O2▸ Their solubility decreases with increasing salinity▸Th i lbilit d ith i i ▸Their soulbility decreases with increasing temperature▸Ocontent in water varies more than in air▸O2content in water varies more than in air▸ Unlike air, water has other life-sustaining components other than gases like dissolved ions components other than gases, like dissolved ions, organic matter and waterPrinciples of Animal PhysiologyRespiratory SystemRespiratory SystemIntroduction▪ Respiration in gill-breathing fishPrinciples of Animal PhysiologyRespiratory SystemRespiratory System▪ Nonrespiratory functions of aquatic respirers▸ Fluid and solute balance♦ Regulate osmotic and ionic gradients▸ Acid-base balance♦ Removal of H+and HCO3-▸ Excretion♦ Removal of ammoniaNi d i l k▸Nutrient and mineral uptake♦ Intake of NaCl and Ca2+Fdi▸Feeding♦ Ciliated gills trap plankton▸Tt ltiPrinciples of Animal PhysiologyRespiratory SystemRespiratory SystemAir Respirers▪ Transition from water to land had its challenges▪Air has much more oxygen than wateryg▪ Air is less viscous than water▪It takes less energy to pump air▪It takes less energy to pump air▪ However, respiratory surfaces must be kept i t f diff imoist for proper diffusionPrinciples of Animal PhysiologyRespiratory SystemRespiratory SystemAir Respirers▪ Since respiratory surfaces must be kept moist for proper diffusion▸ Land animals must remain in moist conditions▸ Land animals must have covered or fully internal structures for gas exchange♦ Internal air tubes - tracheae (insects)♦ Gill-like book lungs (scorpions)♦Mtl iti ( il)♦Mantle cavities (snails)♦ Vascularized sacs - lungs (snails & land vertebrates)Principles of Animal PhysiologyRespiratory SystemRespiratory SystemAir Respirers▪ Book lung of a Spider▸ Modified gill?Principles of Animal PhysiologyRespiratory SystemRespiratory System▪Bimodal breathersAir RespirersBimodal breathers▸ Have gills & another respiratory surface♦Integumentary exchange♦Integumentary exchange♦ Modified gills♦ Digestive system♦ Air sacs (lungs)Principles of Animal PhysiologyRespiratory SystemRespiratory System▪Bimodal breather - FrogsAir Respirersg▸ From eggs, laval stages have gills♦ Uses lungs & skin to breatheg♦ Uses buccal pump to force air into lungs (like fish)♦ Several inspiratory oscillation needed to fill lungs♦ One long exhalation empties lungs♦ O2intake mainly through lungsCOii i♦CO2elimination through cutaneousPrinciples of Animal PhysiologyRespiratory SystemRespiratory System▪Bimodal breather - Frogs - Fig 11-11Air Respirersgg▸ Open nostrils▸Lower floor of buccal cavityLower floor of buccal cavity▸ Air rushes into buccal cavity▸Close nostrils▸Close nostrils▸ Elevate floor of buccal cavity▸Open glottis▸Open glottis▸ Pump air into lungs▸Close glottis▸Close glottis▸ Repeat to inflate lungsK l tti d th t h lPrinciples of Animal PhysiologyRespiratory SystemRespiratory SystemAir Respirers▪ Comparative lung structure of amphibians, reptiles, and mammals▪ Fig 11-10gPrinciples of Animal PhysiologyRespiratory SystemRespiratory System▪Avian respirationAir RespirersAvian respiration▸ Lungs are inelastic▸Several air sacs▸Several air sacs▸ Unidirectional or flow-through▸Membranous diaphragm▸Membranous diaphragmPrinciples of Animal PhysiologyRespiratory SystemRespiratory System▪Avian respiration-Gas exchange surfaceAir RespirersAvian respiration Gas exchange surface▸ Capillaries smaller than mammals: 3-10µm vs 35µm in mammals▸ Air capillaries are not blind-ending, but communicate with each other▸ Diameter of air capillaries do not change during the respiratory cyclepyy▸ Surfactant’s role is limited to restricting fluid movement from blood to air capillaries▸ Mean thickness of the blood-gas barrier is less in birdsPrinciples of Animal PhysiologyRespiratory SystemRespiratory SystemAir Respirers▪ Respiration in birds▪ Fig 11-16Principles of Animal PhysiologyRespiratory SystemRespiratory SystemAir Breathers▪ Movement of pure O2(shaded) through the avian lung▪ Fig 11-16, Part IIgPrinciples of Animal PhysiologyRespiratory SystemRespiratory System▪Nonrespiratory functions of the avianAir RespirersNonrespiratory functions of the avian respiratory system▸Regulation of water loss and heat exchangeRegulation of water loss and heat exchange▸ Circulation - enhances venous return▸Acidbase balance▸Acid-base balance▸ Vocalization, mating calls and other sounds▸Defense▸Defense▸ Removal, modification, activation, or inactivation of various materialsof various materials▸ OlfactionPrinciples of Animal PhysiologyRespiratory SystemRespiratory System▪Anatomy of the respiratory system in aAir RespirersAnatomy of the respiratory system in a mammal▪Fig 1112▪Fig 11-12Principles of Animal PhysiologyRespiratory SystemRespiratory System▪Mammalian respiratory pathwayAir RespirersMammalian respiratory pathwayPrinciples of Animal PhysiologyRespiratory SystemRespiratory System▪Ciliated respiratory epithelium cellsAir RespirersCiliated respiratory epithelium cellsPrinciples