Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

Comparative Physiology

Making heat to lose weight

There are many ways to stay warm on a cold day. We can seek shelter, turn up the thermostat, and huddle close together. Obvious physical adaptations to cold include fur, feathers, and clothing in the case of humans…and some pampered dogs. Blood vessels near the skin may also constrict to prevent heat loss and some animals develop a layer fat under the skin that acts like insulation. We may also […]

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Life at the top

Moving to high altitude requires a bit of an adjustment. One of the ways our bodies adjust to the low levels of oxygen is by making more red blood cells, which are responsible for transporting oxygen in the body. More red blood cells means that our blood can pick up more oxygen. If this process continues unchecked, however, it can lead to chronic mountain sickness, also known as Monge’s Disease. […]

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Chronic stress during pregnancy increases risk of stillbirth and preterm delivery

At the end of pregnancy, levels of the hormone oxytocin increase to stimulate parturition, or childbirth. The stress hormone cortisol is also important for normal fetal development and, like oxytocin, cortisol increases at the end of pregnancy. This may help explain why chronic stress during pregnancy increases the risk of complications such as stillbirth.   A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative […]

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Under pressure: One way our bodies regulate blood pressure

Did you know that blood vessels come fully equipped with the ability to help regulate blood pressure? This is possible because of smooth muscle cells that wrap around blood vessels (see image above). Because they wrap around the inner layers of the blood vessel, when these cells contract, the lumen od the blood vessel becomes narrow and increases blood pressure. When they relax, the blood vessels widen thereby lowering blood […]

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Humans do it, cats do it, dogs do it…why can’t rodents or rabbits do it?

Did you know that rodents and rabbits are not able to vomit? This was certainly news to me. So, I had to find out more… First, let’s talk about the difference between retching and vomiting. During retching (or dry heaves), the diaphragm and abdominal muscles contract, which helps increase pressure within the stomach (and prepare the contents for expulsion). Vomiting also involves contractions of the diaphragm, abdominal as well as […]

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Turning up the heat

There are several ways to stay warm on a cold day. If you are human, you can turn up the heat in your home, put on a sweater, snuggle, and even produce body heat through shivering as well as non-shivering metabolic pathways – although the ability to produce heat metabolically typically declines with aging. If you are a small mammal, turning up the heat or putting on a sweater are […]

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EB 2022: Modeling human diseases and healthy aging

I sat through a very interesting session at this year’s Experimental Biology conference called, “The Power of Comparative Models for Accelerating Translational Healthspan Research: Underutilized Lab Animals, Companion Pets, Old World Monkeys, and Pumas.” While the title seems to capture the general idea of the symposium, I thought I would share a bit more information about the presenters and their exciting research. Dr. Karyn Hamilton from Colorado State University presented […]

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Hurray for Experimental Biology 2022!!

It is that time of the year again…I am so excited to be attending the upcoming Experimental Biology conference! This year’s program is packed with interesting Comparative Physiology sessions including the August Krogh Distinguished Lecture which will be given by Dr. Patricia Schulte from the University of British Columbia. Her lecture is titled, “Physiology in the Anthropocene: Insights from Intraspecific Variation in Response to Environmental Stressors.” Other seminars will include […]

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And a Happy New….Kidney!

Spiny mice (Acomys cahirinus) are amazing animals. For starters, they are reportedly one of the only known species to date, in addition to primates, that menstruate (McKenna et al., 2021). They are also capable of regenerating skin tissue, complete with hair follicles and blood vessels without scarring, after an injury (Siefert et al., 2012). This is an important skill for animals that escape predators by shedding their skin. Add to […]

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Exploring the tree of life

Dr. Yan Wong (University of Oxford) and Dr. James Rosindell (Imperial College of London) have created the most comprehensive tree of life to date. Their tree, a culmination of over 10 years of research (image above, from OneZoom.org), is an exquisite interactive tool that can be used to decipher genetic connections between more than 2 million species. Each tiny leaf represents a single species and clicking on the leaf will […]

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