? Respiration o The problem ? Gas exchange ? Oxygen and CO2 ? Oxygen ? b/c its terminal ? electron acceptor in electron transport chain ? CO2 ? builds up equilibrium in carbonic buffer ? acidic solution ? need to dispose it ? Mechanism ? Always diffusion ? high partial pressure in the air to lower partial Pressure in our lungs and blood ? Blood ? interstitial fluid ? tissue ? blood ? Earth Atmosphere ? 21% O2 - PO2 = 160 mmHg o Mostly nitrogen o At sea level: (.21)(760mmHg) = 160mmHg o PCO2 = 0.23 mmHg ? Dalton?s Law of Partial Pressure o All will add up to 760 mmHg at sea level o At equilibrium ? Partial pressure in air = partial P in water ? Gases will dissolve in water a lot less gas available in the water ? Fick?s Law of Diffusion o Amount of gas that diffuses ? difference in partial pressure increase ? gas diffuse faster o Increase in surface area o Maintain a big concentration gradient to keep blood moving through o Systems of Gas exchange ? If thinner than 1mm ? just diffusion ? (Phylum Platyhelminthes) ? If thicker than 1mm ? circulatory system and respiratory system ? earth worms ? Respiratory Systems ? Characteristics o Thin walled o Moist o Richly vascularized o Surface across which exchange takes place must be thin and moist so gas exchange can go from source to sink easily ? Mammalian System - Humans o Anatomy ? Nares/ Nostril ? hairs block certain particles ? Nasal Cavity ? Conchae ? projections ? increase SA and humidify the air ? Ciliated epithelium ? below nostril ? beat toward pharynx to stomach to destroy crud ? Bernoulli effect ? air comes from small opening, diameter behind nostril increases ? decrease in velocity of air ? Pharynx ? leads to esophagus and Larynx ? Larynx ? voice box ? Epiglottis closes off larynx when swallowing food ? Trachea ? Bronchi (2 branches) ? Bronchioles ? ?mucus escalator? ? conducting zone ? Toxins in cigarettes kills ciliated epithelium, so hacking cough ? Asthma ? smooth muscle constrict when bad is coming through ? throughout the lung ? Alveoli ? end of bronchiole ? Respiratory zone ? Thin walled ? 2 thin cell layers separate the air in alveolus and the blood ? ?tiny little balloon? ? Gas exchange occurs here ? Small and delicate ? too much water can cause it to collapse ? Emphysema o Crude gets down in the alveoli, a lot less surface area for gas exchange ? Pulmonary Surfactant o Like cholesterol o Respiratory distress syndrome o 6 ? 7 months ? like soap has both non-polar and polar ends ? water molecules aren?t coherent ? take your first breathe ? Ventilation ? Positive pressure(frogs) o Swallowing air into respiratory system o Use positive P, put pressure behind air and pushing volume of air in ? using tongue and muscles in pharynx ? Negative Pressure o Inspiration ? breathing in o Expiration ? Intercostal muscle ? muscles between ribs ? used with diaphragm to get more air in and out o When diaphragm pulls down ? volume increase ? pressure decreases ? so oxygen goes in o Rib cage opens a little ? diaphragm pulls down o Controlled by autonomic system ? Medulla oblongata o CO2 must go out or else the pH levels will mess up o pH decreases ? faster breathing kdoshi
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