STL2STM2BookC_StringPrint_SetupTPrintStartupSound_TabLISTBook_PrefsAct List Scene Drawing_Model Draw_Specs diagram_struct_arrayDependentsScriptPad_ListManuscriptPlayPlay_PrefsModelSubscript_Set_ListSubscript_SetArraySimulation_ModelRun_Specsentity_struct_arrayentity_structint16_arraydouble_arraytoken_type_arraytoken_type run_handle_array!Draw_Index"Poster_Info#Poster_Tab$AliasRecord%Play_Where&diagram_struct'Point_array(movie_attach)Picture_Tab*Pad+slider_type,Model_Index-Log_Condn.Log_Page/Model_Index_array0gf_type1graph_type2curve_type_array3curve_type4table_type5table_var_type_array6table_var_type7SET8Pathname9Panel:Sector_Specs;Sense_Setup<select_struct_array=allow_struct_array>allow_struct?Picture_array@Entity_Controller_MapASection_ListBFont_MapCFont_Map_Record_ArrayDFont_Map_RecordEWindow_ListFModel_WindowGPad_WindowH@@nvvvvvxw`w vxxHHE(HH(2}`>>  ,,vvv     vv    JJ  drmd   @N?@@>vvLvvvxv|vdPP??2  VVvPv vvvpvvvv wvw&1 Dim_Name_1 jj@^? Minutes( ~*f@An@dǢ/a?@h@h?@An@dǢ/a@hwD@hr>#y@hGlucose_used_by_cellsBlood_Glucose*Usage_Fraction      !The glucose cell use rate is affected by three processes: 1) conversion of excess glucose to glycogen by the liver & muscles 2) uptake by cells due to cell wall permeability changes 3) conversion of glucose to fat UNITS: milligrams/minute (mg/min) " #'s @Ƞ @ZA@ӈ@p@p@ӈ@Ƞ @ZA@Љݷ@Љݷiy@p?Blood_Glucose 6000 {mg} p!jThis is the amount of glucose that is present in the bloodstream. 70-120 mg of glucose/dl of blood is normal for a person who has been fasting. An average person has approximately 6 liters (60 dl) of blood. Assuming a healthy glucose level of 100 mg/dl, the person being modeled will begin with a normal blood sugar level of 6000 mg . UNITS: milligrams (mg)" #ww@ӈ  *$ffv<tpt@nRenal Threshold for Glucose - Kidneys can no longer conserve glucose. Glucose begins to spill out into urine.%& *$v0tt0@Ȝ8Hyperglycemia - levels of glucose are dangerously high.%&  *$v$tPHNVH. Hn Hn?<pf"(H @2Hypoglycemia - glucose levels are dangerously low%&f @@@@h?@h@h?@@h@h@hy@h Glucose_ReleasetimeXX@(@8@B@H@N@R@U@X@[@^@h@h@h@h@h@h@h@h@h@h@h  !This is the amount of glucose that is released into the bloodstream each minute. Glucose is released into the bloodstream by digestion of food or by the breakdown of fat in the liver. UNITS: milligrams/minute (mg/min) " #f  @@@@w>8؜>@@@@@@@@@@w>8؜>@e|i@mb{Ty@@Insulin_SecretionBlood_Glucose@@@@@p@@@@p@X@@@@È@|@.@U@@g@u@@@@@@x@ !The insulin secretion rate is defined as a graphical function based on the surplus of glucose in the blood. If the glucose surplus equals zero (the body is at the healthy level), the insulin secretion rate is equal to 500 units/min (the amount necessary to maintain the equilibrium amount of insulin. If the glucose surplus is positive, the body will tell beta cells to produce more insulin. This explains the increasing secretion rate as the glucose surplus increases. However, once the surplus reaches a certain high level, the beta cells can no longer produce as much insulin. This explains the decreasing slope as the glucose surplus gets very high. If the glucose surplus is negative, the body does not have enough blood glucose. If this is the case, it would be expected that the body would try to conserve the glucose by slowing down its rate of flow into the body cells. The body does this by decreasing its insulin secretion rate. The decreasing slope of the curve as very low glucose surpluses are reached can be explained by the fact that the body has lower limits to the amount of insulin that it can produce. In the model this lower limit is set to zerothough in reality the beta cells are always making some insulin. UNITS: units/minute" #f @K&@|w5f?@@@@@JSM17@|wolp@K&@|w5f@~çI@~ت~E3!y@@Insulin_Breakdown Insulin/18    !"The insulin degradation rate depends on the amount of insulin and the degradation time constant. Every minute 1/18 of the insulin degrades. Therefore, if there is a high amount of insulin, the degradation rate will be higher than if there is a low amount of insulin. UNITS: units/minute" #s  @K[;@^^ @ӈ@@@ӈ@K[;@^^ @Y)@Y)y@?Insulin 9000 {units}  #(!Insulin is the hormone that is secreted by the islets of Langerhans in the pancreas. Insulin causes an increase in the cell membrane permeability so that glucose may pass from the bloodstream into the cells. UNITS: units " #c @p@p@ӈ@p@p@ӈ@p@p@p@p???y@p?Healthy_Level_of_Glucose 6000 {mg} p!" #c ??{X֙Y?_4x??`A7L?`A7L?{ DY?_+?{X֙Y?_4x?8?82@?`A7L? Usage_FractionInsulin@ @ @@ @@@Ȝ@ @Ϥ@є?~Q?$/?-V?tj~?1&?`A7L?j~#?+ J?lC?p =q?5?|h !The glucose cell use fraction is the percentage of the total amount of glucose that will be taken up by the cells each minute. It is a graphical function dependent upon the amount of insulin. If insulin is at its normal level of 9,000 units, the cells will uptake 3.3% of the available blood glucose. If insulin is higher than the normal level, the cells will take up a larger fraction of the glucose. The fraction taken up will increase until the insulin level gets too high and the cells are unable to take in as much glucose as the insulin would like to allow. At some point the fraction levels off because the cells can no longer take in a greater fraction of the glucose. If the insulin is lower than the normal level, the cells will be able take up only a smaller fraction of the available glucose.. As insulin decreases, the fraction of glucose taken up decreases at a slower rate because the cells, which need the sugar for energy, will continue to take up as much as they possibly can given the available insulin. UNITS: dimensionless " #  )   )'aR@]( E()*+,hh v?-./&" " 0 ' t@a  j}i()*jZoom in on the Blood Glucose or Insulin graphs by clicking the + in the model window's lower left corner.+0 '' tA@AWp 9_x()*mg (total in blood)+0 ' DcVn()*Graph 1+0 ' t@ ()*mg or units (total in blood)+0 ' t;z@;zQ  "3rY(()*"mg/min (rate released into blood)+0 ' t@ E  ()*E Scroll to right ---> For facts about Insulin and Glucose.+0 ' t .@ .  &()* INFORMATION: Glucose, Insulin, and the Role of the Pancreas GLUCOSE. Glucose, a simple sugar, is the main energy source for most organisms. The human body makes glucose from food and transports it to cells via the bloodstream. Glucose is measured in milligrams per deciliter of blood. The average healthy human has about 60 dl (6 l) of blood and a between-meals blood glucose level of about 100 mg/dl or 6000 mg circulating in the blood. (The range for a person who has been fasting is 70 to 120 mg/dl.) The amount of glucose in your blood varies with your food intake and your livers breakdown of fat to make glucose. Glucose release is measured in mg/min. PANCREAS. Your pancreas regulates your blood glucose level by secreting the hormone insulin in response to an increasing glucose level. The pancreas secretes insulin in groups of beta cells called islets of Langerhans, after the German scientist who first described them. As insulin circulates in the blood, your bodys cells draw glucose from the blood. Your glucose level decreases, so the pancreas secretes less insulin. This mutual relationship between glucose and insulin is an example of feedback, and works much as a home thermostat controls room temperature. INSULIN. Insulin helps cells take in glucose by making the cell membrane more permeable to the sugar. The normal insulin secretion rate is about 500 units/min, the amount necessary to maintain equilibrium between insulin and glucose. This equilibrium is essential to homeostasis, the normal stable condition of the human bodys internal environment. Insulin level is measured in units (1 unit = 1 mg) and insulin secretion rate in units/min. GLUCOSE USE. Cells use glucose to fuel their energy requirements. Glucose not needed for energy is converted to glycogen in your liver and muscles. These cells change glycogen back to glucose when the body needs it. The body stores excess glucose as fat. Glucose use rate is measured in mg/min. INSULIN BREAKDOWN. Insulin degrades soon after secretion. Every minute 1/18 of the insulin in the blood degrades. At higher insulin levels, more insulin is degrading than at lower levels, that is, the degradation rate is faster at higher insulin levels. MODEL. This model simulates the bodys reaction to eating food: how much and what kind of food, how long ago, how fast digestion proceeds, and how soon your pancreas reacts. The insulin secretion rate is defined as a graphical function based on the surplus of glucose in the blood. If your glucose level is normal (homeostatic), no excess glucose exists. The surplus is zero and insulin secretion rate is about 500 units/min, maintaining homeostasis. If the surplus is positive, the insulin secretion rate increases until it reaches a limiting level that the beta cells cannot maintain. The rate begins to decline despite a high glucose level. If the surplus is negative (a glucose level lower than homeostatic), the insulin secretion rate decreases as the body conserves glucose by slowing down the rate at which cells take it in. Beta cells also have a lower limit on insulin production. In the model this limit is set at zero, though in reality the beta cells are always making some insulin.+0 ' D@M* ()* Table 1+0 ' t@ V '()*VDouble-click this small graph to open the graphical function, called the input graph.+0 ''Gv.. R()*+1((@@vv v@(@8@B@H@N@R@U@X@[@^@h@h@h@h@h@h@h@h@h@h@h-0 '' t^^t@ V |H()*20000+0 '' D#q *^A()*Graph 2+0 '' t''< D()*0+0 '''' t+?  3G()*20000+0 ' t  ()*Scroll up for directions. +0 ' t++@ #H()*0+0 ' t77( /0()*+0 '''''''''''RI@+$AER()*+,v?-./&" " 0 '' t O ( &0()*+0 ' t5:' =()* Glucose 1+0 ' t001 ((9()*In this activity you will simulate the relationship between the human body's blood glucose level and its insulin production. Scroll down to see the main screen. Center the thick-bordered box in the window. Double-click the small Glucose Release graph to open it. Click inside the graphical function (input graph) to draw a curve of how much glucose will be released from the digestive system into the bloodstream over time. Click OK. Set the initial glucose release at about 200 mg (this rate may already be set). Choose "Run" from the Run menu to run the simulation. Continue the activity on your student guide pages. This window is the top level of the STELLA simulation. If you would like to see the underlying model, click the down-pointing triangle in the upper left corner of the screen. The next down- pointing triangle leads to the equations. Click the up-pointing triangle to come back to the graphs. IMPORTANT! If you change this model, be sure to save it under a different name. DO NOT SAVE THIS FILE UNDER THE SAME NAME. UNITS: mg = milligrams (6000 mg total blood glucose is approximately equal to a concentration of 100 mg/deciliter blood)+0 drmd     t' fE  S_;(55W)*(++U+0 ' d7  .@)()*+0 ' d6_ -V?h()*+0 ' s2 "S()*+0 '' fEn   S;l(5(5)*(+&++0 ' dX Oa()*+0 ' f)) X(`)*(+0 ' f4 n (y)*(.+0 ' d x()*+0 ' a )$ ((!1()*+0 ' s   ()*+0 '' t ()*+0 '' cc{  VY()*+0 '' aU $i}()*+0 '' c31()*+0 ' a`o$I$&&II_pDet_p()*+0 ' a+*$pp**<Z()*+0 ''''''' apheii4e()*+0 drmdHG +66w0wWEsu$uw`vvpv 2ZZvvv@^~8@^+Blood Glucose vs Minutes3 4Bv?xe+-4v?xe+-" +ww@Esuuw`vvpv 2 vvv@^~8@^+Insulin vs Minutes3B4v?z1&-" +#lwܰwPh uuwPvvp v 5bbvvv?@2~8w +Untitled Table-67"v-!7v-!7v-!7v-!7v-!7v-!8 z" %9 >~= <vPvhvDvvpw`v`  vtv`      drmd N : vtv@   :   drmd ~  vtv       drmd  vtvlv  ;w8T???@ A-"  Bv2CDEGenevaEGenevaE::Gill Sans Condensed BoldBF  G *{G0&DH `]+HR +Hl{+