Heersink-1ControlSystemsRepresentationsoftheGlucoseInsulinRelationshipandApplicationsforaPseudo-PancreasJeremyHeersinkAbstract – Control Systems can be used to model thefunctions of a Pancreas and the beta cells therein.Glucose and Insulin have a documented relationship,and using that relationship, a transfer function in the s-domain can be found. A control systems applicationcan be implemented using this transfer function in theSimulink toolbox in the MatLab software program.This can then be used as a simple example of the way apseudo pancreas can be implemented. Also discussedare the causes, effects, and essence of diabetes, and fromthis, a discussion of typical and new treatments fordiabetes.Index Words – Diabetes, Control Systems, PseudoPancreas, Insulin, Glucose, modeling, computersimulationI.INTRODUCTIONHE concept of control systems generally applies torobotics control, automation, and many othermechanical/electrical situations. However, using thesetools for biological purposes also helps to give insight intothe modeling and function of many items. Biology is bynature a feedback controlled system that, based upon aninput, will do what it needs to in order to achieveequilibrium. One such item that can be easily modeled isthe pancreas. The pancreas is an organ that producesinsulin. Insulin is a hormone secreted by the pancreas thathelps to metabolize glucose, a common chemical found inmany foods. Glucose is the main chemical in most sugars,and has a chemical formula of C6H12O6. When the humanbody and pancreas do not control the flow of glucose in thebody,adiseasecalleddiabetesiscommon.TI became interested in diabetes about 7 years ago when Ifirst took a biology class in high school. At the time, I onlyknew that my uncle had a bad case of diabetes. I canremember many times staying at my uncle's house andhaving to wake up the rest of my family because my unclewas having a fit because of his diabetes and the blood sugarconcentration not being at a normal level. I can evenremember a few times that an ambulance needed to comeand take him to the hospital for treatment. As a youngchild, I can remember these images frightening me. Thenin biology class in high school, I really wanted to explorethis disease more and see what made this disease sodangerous for my uncle. I can remember during that classdoing some research and looking into a pseudo pancreas.The technology at the time was very new and had not beenimplemented fully. Now, as a senior engineering majorstudying control systems, I can see more fully how thepseudo pancreas can work and how such types ofapplications of control systems makes this an important andcross-disciplinedfield.II.DIABETESBACKGROUNDThere are two types of diabetes. The first is TypeI otherwise called Juvenile Onset Diabetes. The secondtype is called Type II or Non-Insulin Dependent Diabetes.Each has different demographics and treatments to itssymptoms.[6]A.TypeIDiabetesType I diabetes is traditionally called Juvenile OnsetDiabetes. This is because it generally shows up duringadolescence or younger. Type I diabetes accounts for 5-10% of all cases of diabetes, however, this is probably thetype of diabetes most people are familiar with. Treatmentsof Type I diabetes include daily insulin shots, blood-glucose level monitoring, diet, physical activity, andcontrolling blood pressure and cholesterol. Type I diabetesis caused by the beta cells of the pancreas no longer makingandsecretinginsulin.[6]Manuscriptsubmittedon19December2002toProfessorRibeirooftheCalvinCollegeEngineeringDepartment,GrandRapids,MI,USA.J.Heersink(email:[email protected])isaseniorEngineeringstudentatCalvinCollege,GrandRapids,MI,USA,withaConcentrationinElectrical/ComputerEngineering.PlannedGraduationDateofMay2003.Heersink - 2B. Type II DiabetesType II diabetes is also sometimes called Non-Insulin Dependent Diabetes or Adult Onset Diabetes.This generally affects older or obese people. In this type ofdiabetes, the pancreas still makes insulin, it just can't makeenough to fully metabolize the glucose taken in.Treatments for type II diabetes include taking diabetesmedicine, dieting, physical activity, taking aspirin daily,and controlling cholesterol and blood pressure. [6]C. Gestational DiabetesGestational Diabetes is another less common typeof diabetes. This occurs in women occasionally duringpregnancy. If a woman has had gestational diabetes, she ismore likely to develop Type II diabetes later in life.Gestational diabetes is caused by hormones of pregnancy ora lack of insulin during pregnancy. This form of diabetesusually goes away after the child is born. [6]D. Taking care of DiabetesAs mentioned in the descriptions of the types ofdiabetes, there are treatments for diabetes. As of now,diabetes is an incurable disease; it can only be controlled.Common to all types of diabetes is the treatment of diet,physical activity, controlling cholesterol and bloodpressure. [6]Diet is one easy way to control diabetes. If aperson can control the amount of glucose coming into thebody, the amount that the pancreas and insulin has tocontrol is less, and can be less of a spike to the system.Using control systems as a comparison, a spike to anycontrol system can cause the system to go off into infinityor oscillations. Figure 1 is a good example of an output toa system that is oscillating and expanding. If this were anelectronic system, it would probably explode. If this were abiological system, the organism would more than likely die. Another means of helping to control diabetes isphysical activity. The reason this helps control diabetes issimply, it helps overall health. Because poor overall healthcan be a detriment to the way the pancreas and the rest ofthe body works, controlling the way the rest of the bodyworks does help diabetes. Controlling blood pressure and cholesterol alsohelp because if the blood system is working properly, thebody can more easily use the insulin that is in the system,and thus take care of the glucose in a much better way.III.POSSIBLE CURES FOR DIABETESAlthough diabetes has no cure, many scientists
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