Object Type:    hillpump

Description:    A simple model for the store membrane pump (SERCA), similar
                to the mmpump, but with a Hill exponent.

Author:         E. De Schutter BBF-UIA 11/97

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ELEMENT PARAMETERS

DataStructure:	hillpump_type [in src/concen/conc_struct.h]

Size:           92 bytes

Fields:         vmax            maximum pump velocity, scaled by mebrane
                                surface area.  i.e., max ion flux in moles/sec.
                Kd              disassociation constant
                Hill            Hill exponent

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SIMULATION PARAMETERS

Function:	HillPump [in src/concen/hillpump.c]]

Classes::       gate segment

Actions:        CHECK  RESET  PROCESS  INIT

Messages:       MMKD   Kd  (changes Kd value)

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Notes:

The hillpump is similar to the mmpump, and is coupled to a difshell to reduce
the concentration in the shell, and to a concpool to increase the
concentration.  The message "HILLPUMP vmax Kd Hill" to a difshell causes the
concentration to change as dC/dt = -vmax*(C^Hill/(C^Hill+Kd)/vol.  When sent
to a concpool, it changes the concentration with the opposite sign.  Note that
the maximum pump velocity vmax should have previously been multiplied by the
membrane surface area, so that it is in moles/sec.

This does not have the electrogenic effect (Ik) calculation of the mmpump.  It
gets Kd from a MMKD message (or a setfield), and simply stores Kd, vmax, Hill,
letting the difshell or concpool do the calculations.

Example:	

See also:	mmpump, difshell, concpool
