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The vascular system is modelled by a group of "beans" called "Vessels" and "Flows". The first use of this "circulation" is simply to carry gasses so I have not put too much effort into tuning it.
The properties of blood vessels that can be read or written to are the independent variables:
 | "volume" (ml) |
| "capacity" (ml) |
| "compliance" (ml/mmHg). |
From these the dependent variable is derived:
| "pressure"(mm/Hg) [pressure = (volume-capacity)/compliance] |
This is a screen shot of a window into a blood vessel.
When the model is not running you can enter values for blood volume, capacity and compliance of the vessel . You can see the effect on pressure.
There are 7 Blood Vessels in the current model|;
| Systemic artery |
| Systemic capillary |
| Systemic vein |
| Pulmonary Artery |
| Pulmonary ideal capillary |
| Pulmonary shunt capillary |
| Pulmonary vein |
The "Blood Vessel" beans are connected by "Blood Flow" beans.
Flow beans determine how much blood will pass from an upstream vessel to a downstream vessel in a given increment of time. (Every 1/100 of a second in the current model)
The calculations are reasonable involved!
Two specialised flow beans are the "left heart" and "right heart"
At each heart beat the right heart takes the stroke volume
of blood out of
systemic vein and places it into the pulmonary artery.
At each heart beat
the left heart takes suffiecient blood from the pulmonary vein down to
reduce its pressure to the "wedge" pressure. this volume
of blood is placed in the systemic artery.
Improvements to the vascular model would include:
| The right heart should respond to venous pressure rather than have a fixed stroke volume. |
| Agreed reference set of values for vessel capacities and compliances |
I am open to suggestions or assistance. :-)
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