BIO120H1 Lecture Notes - Lecture 15: Lungless Salamander, Ideal Gas Law, Gas Exchange
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BIO120H1 Full Course Notes
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Henry"s law describes how gases dissolve in liquids. Gases diffuse at different rates: diffusion rate is proportional to solubility and inversely proportional to the square root of its molecular weight. Resistance opposes flow: bulk flow is proportional to the pressure gradient and inversely proportional to resistance. Very thin animals can rely on diffusion alone for gas exchange. Gills originate as outpocketings or evaginations of the body surface and can be external or located within a respiratory cavity protected by a flap or other covering. Lungs originate as infoldings or invaginations of the body surface forming an internal body cavity that contains the external medium. Gills used commonly in water, lungs on land though there are exceptions to this. Ventilation and gas exchange in water: sponges, beating of flagella on choanocytes cause water to flow into pores called ostia into a central cavity called the spongocoel.
