'Find a recent paper (last 5 years) related to the function of the cardiovascular system, avoiding reviews; that you will present to the group next week'
In order to make this slightly more interesting, I'm blogging about my topic.
You may recall last time I blogged I mentioned my EPQ on bat wings... well, as part of that EPQ I wrote a very brief summary of adaptations in the bat cardiovascular system for powered flight. I didnt really understand much of it at the time, and as it only made up a few small paragraphs in the report I didnt include much detail. After posting the blog a few days ago I reread my EPQ, leading to my decision now to try to improve my knowledge on this topic.
So.... my findings for my EPQ were basically that: the bats heart is very large relative to its body size, with smaller cardiac muscle fibres than for other mammals. This allows more fibres to be compacted into a smaller volume. The venous system (veins) is also different from other mammals as if acts as a storage reservoir for blood, and contains special shunts to help control blood flow. The storage reservoir could have a function in heat regulation during flight or hibernation.
My research paper is entitled 'Application of local heat induces capillary recruitment in the Pallid bat wing'.
If the dilation of the arteries is inhibited by a blockade of a protein called NO synthase, the blood flow through the wing still increases when heat is applied. The aims of the study were to see if this is due to the capillaries.
Bats were trained to remain resting in a box while the heat was applied, and various pieces of equipment were used to take measurements.
There were three main experiments carried out, and each one was tested both with and without the pharmacological blockade.
1. The first aimed to measure the response of the arterioles to local heat, by finding out the blood vessel diameter and the red blood cell velocities
The results from this experiment confirmed the previously known results by showing that the blockade prevented any dilation through the arterioles. The blood flow in the wing, however, continued to increase despite this.
2. The second measured capillary perfusion (ie how many capillaries were in use). With heating, the number of capillaries in use increased, and this was unaffected by the blockade.
3. The final one measured the activity of structures called precapillary sphincters (which basically open and close to allow blood through the capillary or not). Similarly to experiment 2, the sphincters stayed open for longer and were unaffected by the blockade.
The results showed that capillary recruitment is induced by local heat, and this is independant of the blockade of the substances. The mechanisms through which this acts are currently unknown, but the results suggest some interesting potential causes.
The techniques have been suggested to be of some use to humans, with possible uses for diagnosis of diabetes and kidney failure.
All credit to the authors of the paper: Widmer RJ, Stewart RH, Young MF, Laurinec JE, Laine GA, Quick CM. http://www.ncbi.nlm.nih.gov/pubmed/17332157
Even if the
morrow is barren of promises, nothing shall forestall my return...
Becky x
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