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This article quotes a professor of respiratory physiology that says "dogs are built to pant just right. The mechanics of their lungs and chest set a precise rate for panting that minimizes the amount of work while maximizing cooling power." They also don't breathe fully when panting, so they can still cool themselves without increasing gas exchange. This is ...


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The glycogen in the liver begins providing blood glucose. Muscle glycogen is used as fuel by the muscles, fat cells (adipose tissue) release fatty acids to manufacture ketone bodies in the liver and to be used by the brain as fuel, and body proteins are converted to glucose. In short, the body's metabolism shifts to catabolic reactions. If this continues ...


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This is more about basic physics than biology. When you hold your breath, you normally take in one last long breath and keep it in as long as possible, Your lungs are therefore already full of gas (remember that the oxygen used by our lungs is only ~22% of the total volume of air you inhale). Therefore, when you release that breath and want to take in a new ...


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Yes, they are mostly exhaled. The carbon, hydrogen and oxygen that the fats are made of recombine to become $CO_2$ and $H_2 O$ and are exhaled. It's the same overall chemical reaction as if the fats / carbohydrates were burnt, except it's by a different pathway, and the energy produced goes (mostly) towards driving other chemical reactions rather than ...


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For a start, in addition to the International Space Station (ISS), also look at gas mixtures used in scuba diving and breathing gases.


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This shows the major biological transformations of carbon in any system (not just lakes). On the Left Side: $GPP$ (Gross Primary Production) is the total amount of $C$ from atmospheric $CO_2$† that is reduced into organic molecules during the calvin cycle of photosynthesis. This is the process performed by photosynthetic organisms like green ...


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According to Wikipedia "In a healthy, young adult, tidal volume is approximately 500 ml per inspiration..." (tidal volume is the volume inspired/expired) Using this figure, together with values for gas composition also taken from Wikipedia, I estimate that in each breath we take in 18 mg O2 (1.1 mmol) and we release 36 mg of CO2 (1.2 mmol) plus 20 ...


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The switch from glucose to ketone bodies as the principal blood metabolite accompanies starvation. This prioritizes the heart, which preferentially uses ketone bodies as a fuel (update; actually it's fatty acids, but they're metabolically similar.) This de-prioritizes the brain, which preferentially uses glucose. [edit] I was asked for a source. This is ...


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Inhalation and exhalation happen sequentially as Herman stated in the comments. Yes, your general understanding of inhalation is correct. After the air gets into the lungs, the oxygen is diffused into the capillaries covering the alveoli. The now oxygenated blood travels back to the heart to be circulated throughout the body. As this blood enters ...


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Since the question is about risk specific to e-cigarette as opposed to classic cigarettes, what's left is the potential harm from the chemicals in refill-fluids (apart from nicotine): polyethylene glycol, glycerol, alcohol, linalol, flavours. You can find cytotoxicity experiments (e.g. http://www.sciencedirect.com/science/article/pii/S0890623812002833), that ...


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Good question. If you inhale on top of inhaled air this is more work. There is more dead air, air which is not as useful due to the lower concentration gradient. And we breathe more to exhale carbon dioxide than we require oxygen. Low oxygen levels only push us to breathe when oxygen levels are a good deal lower, however tiny changes in carbon dioxide ...


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I am not sure, if any comparisions have been made with other plant leaves, but unless these contain some pharmacologic active substances, I doubt that they are smoked widely. There are comparisions between normal smoking and the smoking of marijuana and the short version is: Both are harmful. It depends on the temperature at which they are burned, how they ...


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(at an epidemiological scale) WHO on tobacco more than one billion smokers worldwide... Tobacco kills nearly 6 million people each year. WHO on indoor air pollution Around 3 billion people still cook and heat their homes using solid fuels in open fires and leaky stoves. About 2.7 billion burn biomass (wood, animal dung, crop waste) and a ...



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