Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

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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Buoyancy and Balance

Existing species of coelacanths (pictured above) are descendants of a group of fish that existed about 410 million years ago, during the early Devonian period. They can be found in the Western Indian Ocean off the coast of Indonesia. These fish are really interesting because they have very low metabolic rates. In fact, their metabolism is among the lowest of any other existing vertebrate. Even sloths are jealous of their […]

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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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Nitrites and noses

If you have ever had a fish tank, you may be familiar with monitoring ammonia levels in the water. Ammonia levels can rise due to overcrowding, overfeeding, as well as fish waste. Nitrite levels in the water also require monitoring as nitrite can bind to hemoglobin, which prevents oxygen from binding. In effect, by preventing oxygen from binding, the fish can succumb to hypoxia. Hannah Hughes, a graduate student working […]

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More than milk

Prolactin is an important pituitary hormone in mammals that works with oxytocin to provide milk for offspring. It also plays a role in promoting bonding between new mothers and their offspring. But did you know that non-mammalian vertebrates have prolactin too? Considering non-mammalian organisms do not have mammary glands, it must serve a different purpose in these animals.   As it turns out, prolactin is very important in the ability […]

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Geriatric bees

Jacob Pithan, a graduate student in the laboratory of Dr. Kendra Greenlee (North Dakota State University), presented their research examining how aging affects exercise performance as well as oxidative health at last month’s Experimental Biology conference in Philadelphia. The oxidative stress theory of aging postulates that aging results from an overproduction of free radicals along with a decrease in antioxidants that can scavenge them. The problem with free radicals is […]

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Grappling with gravidity

In humans, pregnancy can be an uncomfortable time as the growing fetus makes it more difficult to breathe. It can also become more difficult for the expectant mother to get around. It may be surprising to find out that grasshoppers may develop similar issues when they are ‘expecting’. In fact, a gravid grasshopper can carry an egg mass that makes up as much as 40% of their weight! Could you […]

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EB 2022: Seals, seals, and more seals

Several posters at EB 2022 in Philadelphia this month were focused on understanding the remarkable physiology of diving seals. Although we may think of the image below when we picture seals, they really are quite the athletes in water. Kaitlin Allen (a graduate student working in the laboratory of Dr. José Pablo Vázquez-Medina at the University of California Berkeley) presented her research on Northern elephant seals and how these animals […]

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EB2022: Facing Oxygen Challenges

I learned a lot about how animals adapt to changing environmental oxygen levels in the Experimental Biology symposium on “Functional Integration across the Oxygen Cascade in the Face of Challenging Environments.” Here is what I learned… The first presenter, Dr. Lara do Amaral-Silva (postdoctoral fellow at the University of North Carolina at Greensboro working with Dr. Joseph (Joe) Santin), spoke about her research on adaptations in the bullfrog “super-brain” that […]

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