2 possible scenarios I thought about that I can represent as a complex system:
1)The human body. But I wanted to display a scenario where the body, as a system, fails due to hypothermia.
I will have a step by step sequence of how the individual body parts, skin, etc are affected by this situation, and how, unless the person leaves the hostile environment, will start experiencing organ failure, step by step.
soft points: the persons endurance in the cold
hard points: the outside temperature, body temperature.
2) Coalition forces have been in Iraq since 2003. US combat troops withdrew this year, and Iraqis handle their own affairs.
Many internal and external forces will make or break the new Iraqi democracy... examples are Iraq's neighbors and their influence, most importantly Iran. Other examples can be internal, such as whether the Sunni minority will accept a Shia majority government, and other variables. These factors can be represented as probabilities, once all put in a system can give as the chances of Iraq becoming a successful sovereign nation, or descend into more civil war.
Hard points: success of next election, nature of US- Iran relations
Soft points: whether the insurgency will go after US withdraws
For the human body example, i think there are a few more hard points you could look at as well to help evaluate the state of the body. Heart rate, blood pressure, and breathing rate would all be fairly easy to measure. It would also not be too difficult to measure (although it would require more sophistocated tests) various compounds in the blood by taking samples over time and analyzing to see what changes. Those chemicals may help to evaluate which organs are failing, i.e., more billirubin may indicate liver failure, etc. It seems like if you wanted to model the body as a complex system you would need at least a few more hard points besides heart rate to get a good model (although may be wrong, it wouldn't be the first time).
ReplyDeleteYay, a neuroscience-related topic!!! I can be helpful to you, considering all the years I put into this stuff. I have several recommendations for things that should be included in such a model, depending on your scope, of course:
ReplyDelete1) The hypothalamus is a tiny midbrain structure in the diencephalon, and the posterior nucleus is the hypothalamus region that is responsible for both determining a temperature "set point" at which the body should remain and initiating a chain of events that change the body temperature if it strays from the set point (a balancing loop!). For example, if your body temperature drops below the desired set point, temperature-sensitive neurons in the posterior portion of the posterior nucleus become activated, and set off a chain of events that causes the body to gain heat [e.g. shivering behavior, vasoconstriction (constricting blood vessels), and blockage of perspiration]. Because vasoconstriction would result from hypothermia, you could measure the level of antidiuretic in the blood stream. The hypothalamus is the "master hormone control center" of the body in general, as well, so this is a really great place to start first.
2) Focus on *why* low body temperature is bad for the body. We know that it is bad, but few people without biology backgrounds actually understand the mechanisms involved. To answer this question, be sure to address the fact that all life is crucially sustained by protein enzymes that catalyze so many important biochemical reactions in our body. However, the catch is that our enzyme structures are in perfect harmony with the pH and temperature of their surrounding environments (i.e. our body). If either of those two components changes significantly, the physical structure of those enzymes will change, and they will no longer be able to function. This knowledge will help you target your search for where the failures are occurring throughout the body.
3) Temperature sensation at the level of the skin occurs through TRPV channels embedded in skin peripheral neurons. This will provide a good starting point if you want to trace temperature-sensitive signaling cascades throughout the body that produce behaviors in response to falling temperatures.
I figure these three points will be a good place to start. It is indeed a very complex system!
Excellent feedback! I was going to review and add more information but Robert's additions beat me to the point, and thank you Nathan for explaining the complexity with indeed complex but exact language. I think this is still an interesting possible model, albeit highly complex. And one should not be surprised, as mapping just the brain as a sysytem, let alone the whole human body and its connections to the brain, will be a tremendous task.
ReplyDeleteTarek Hamid (Navel Post Graduate School faculty) has developed an extensive system dynamics model of the human metabolic system, with a focus on energy management and weight management. His model depends on a through analysis of the body's processes at the biochemical and cellular level. He's published this work in very engaging book entitled "Thinking in Circles about Obesity". It's worth checking out!
ReplyDelete