Chapter 9
Iodine Compartment
Iodine was discovered accidentally, about the beginning of
the year 1812, by M. Courtois, a manufacturer of saltpetre
at Paris.
(Henry, Elem. Chem. I., 1826)
9.1 Iodine Compartment Model
The previous two models focused, respectively, on chemical reactions within a cell,
and on the activities of an entire cell. In this chapter we model the flow of a
substance—iodine—among different parts of an organism. This is a donorcontrolled model.
Iodine is found in three places in the body: the thyroid gland, tissue connected to and
surrounding the thyroid gland, and inorganic iodine in the circulatory system. Figure 9.1 shows how the flow balance is established for each of the stocks representing
each of the places that iodine can be found. For our model (Fig. 9.2), inorganic iodine is
constantly injected into the system at 150 μg/day, for example, through certain foods,
or iodized salt. This exogenous iodine input is denoted D i in Fig. 9.1.
Note that all flows are donor controlled. This of course is not the case in all
models. The Extra Tissue is that immediately adjacent to the thyroid. The Inorganic
Iodine is in the blood stream.
The thyroid gland is consuming inorganic iodine and some leaves the system
with urine. Ultimately, the remainder leaves the digestive system as feces. Conversion rates required to specify the flows from compartment to compartment are
assumed to be dependent on the amount of iodine in each place. This is a questionable assumption that nevertheless is supported by experiment.
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_9,
© Springer International Publishing Switzerland 2014
81
Iodine Compartment
Iodine was discovered accidentally, about the beginning of
the year 1812, by M. Courtois, a manufacturer of saltpetre
at Paris.
(Henry, Elem. Chem. I., 1826)
9.1 Iodine Compartment Model
The previous two models focused, respectively, on chemical reactions within a cell,
and on the activities of an entire cell. In this chapter we model the flow of a
substance—iodine—among different parts of an organism. This is a donorcontrolled model.
Iodine is found in three places in the body: the thyroid gland, tissue connected to and
surrounding the thyroid gland, and inorganic iodine in the circulatory system. Figure 9.1 shows how the flow balance is established for each of the stocks representing
each of the places that iodine can be found. For our model (Fig. 9.2), inorganic iodine is
constantly injected into the system at 150 μg/day, for example, through certain foods,
or iodized salt. This exogenous iodine input is denoted D i in Fig. 9.1.
Note that all flows are donor controlled. This of course is not the case in all
models. The Extra Tissue is that immediately adjacent to the thyroid. The Inorganic
Iodine is in the blood stream.
The thyroid gland is consuming inorganic iodine and some leaves the system
with urine. Ultimately, the remainder leaves the digestive system as feces. Conversion rates required to specify the flows from compartment to compartment are
assumed to be dependent on the amount of iodine in each place. This is a questionable assumption that nevertheless is supported by experiment.
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_9,
© Springer International Publishing Switzerland 2014
81