// Cardiovascular system - Frank-Starling-Baroceptor
// Set up for cardiac function curves
// Contractility (cardiac function) is increased progressively

IndVars: CNT
DepVars: Va,Vv,CVP,MAP,COL,HR,SV
Params:


//Fixed parameters
  CPLv = 0.45
  CPLratio = 20
  Vblood = 3.5
  SVR = 17

//Calculate arterial compliance
 CPLa = CPLv/CPLratio

//Calculate unstressed volumes
//At MCP, Vv/CPLv = Va/CPLa and Va + Vv = Vblood
  Va0 = Vblood/(CPLratio + 1)
  Vv0 =  Vblood-Va0

//Calculate pressures
  CVP = Vv/CPLv
  MAP = Va/CPLa

//HR control
  MAPset = 100
  HRgain = 2
  MAPdelta = MAPset-MAP
  HR = MAPset + MAPdelta*HRgain

//Calculate stroke volume
  kc = 0.0000075
  SV = CNT * kc * CVP

//Calculate cardiac output and venous return
  COL = SV*HR
  COR = (MAP-CVP)/SVR

//Differential equations for volume changes
  Vv' = COR-COL
  Va' = COL-COR

//Parameter values
  0 < CNT < 3000

//Initial conditions
  t=0
  Vv = Vv0
  Va = Va0