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Doctor Dolittle Visits a Sitting Case 

Doctor Dolittle Visits a Sitting Case
Doctor Dolittle Visits a Sitting Case

James R. Munis

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date: 09 May 2021

Any acceptable model must explain why the cerebral circulation must be robust enough to contend with different head positions yet continues to work in weightless environments (ie, during space flight) and it must explain the clinical phenomenon of air embolism, which is what happens when air gets sucked into perforated veins or sinuses when the surgical site is above the heart. 2 models of the cerebral circulation: the first is a common-sense model that most of us would draw without having thought about it much; the second is a model that makes a lot more physical sense and answers the questions above in a way that the first model cannot. The main difference between these models is that the correct one takes into account the principle of the siphon, whereas the incorrect one does not. A siphon is any arrangement of fluid-filled tubing that excludes air and is open on both ends to allow flow. It happens that the cerebral circulation functions like a siphon.

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