Life Lines by Dr. Dolittle

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Tag Archive for ‘hypoxia’

Physiology in Arizona

The Arizona Physiological Society will be hosting their 12th annual meeting Friday and Saturday on the Arizona State University campus. Physiologists from all over the state will be meeting to talk about a variety of topics ranging from comparative physiology to clinical trials. The 2019 Arizona Distinguished Lecturer is Dr. Ralph Fregosi from the University of Arizona in Tucson who specializes in respiratory physiology. The Keynote speaker will be Dr. […]

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Adults are better adapted to survive without oxygen

Adult fruit flies (Drosophila melanogaster) are more tolerant of environments devoid of oxygen than their larvae. In fact, they are able to survive up to 12 hours without oxygen by becoming paralyzed, which enables them to dramatically reduce metabolism and the need for oxygen. In contrast, Drosophila larvae expend a lot of energy trying to escape and are only able to tolerate a couple of hours without oxygen. This is surprising […]

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Remarkable hypoxia and cold tolerance of rodents native to the Tibetan plateau

The plateau zokor (Eospalax baileyi) is an underground dwelling rodent species native to the Tibetan plateau (2000-4200 meters in elevation). A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology explored how these animals were adapted to extract oxygen from an environment with very low levels (83-88% of atmospheric). Hemoglobin molecules found in red blood cells are responsible for binding oxygen and transporting it to tissues […]

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High altitude deer mice have less stress?

Animals that live at high altitude have evolved a number of physiological adaptations to deal with the low atmospheric oxygen concentrations (hypoxia). For low altitude acclimated animals, short exposures to high altitude results in activation of the sympathetic nervous system (i.e. the fight or flight response). This is a good thing because activation of this system results in more blood flow, especially to the heart and brain to help protect oxygen […]

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Lactate directly increases breathing

Hypoxic environments increase ventilation in animals. This helps to bring in more oxygen when environmental levels may be limited. With limited oxygen availability, the body turns to anaerobic metabolism, resulting in the production of lactate ions. These ions are known to indirectly stimulate breathing by lowering blood pH and were more recently discovered to directly stimulate the carotid body to increase breathing. For this reason, lactate ions are thought to […]

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Hypoxia and anoxia and reoxygenation, Oh my!

There are many examples of animals that can naturally tolerate hypoxic and anoxic conditions without exhibiting pathologies associated with reoxygenation. Here are a few examples from this year’s conference: Dr. Anthony Signore (University of Nebraska) spoke about how some hypoxia tolerant animals can use carbon monoxide, you know that gas we think of as poisonous, to improve oxygen binding to hemoglobin in hypoxic conditions. Well known for their ability to […]

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How Animals Deal with Stress

  Victor Zhang (Graduate Student working with Dr. Loren Buck at Northern Arizona University) gave an interesting talk on his research to measure stress and activity patterns in free living arctic ground squirrels. They found overall that females were less stressed than males although stress levels and activity varied during lactation. I think some human mothers can agree with those observations. Oliver Wearing (Graduate student working with Dr. Graham Scott […]

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