HPA-aksens dynamik - fra biologi til matemaik: The dynamics of the HPA-axis – from biology to mathematics

Bassam Tawfik, Florian Hermann, Hammer Katrine, Lena de Thurah, Malene Nielsen & Tore Holm Hansen

Studenteropgave: Semesterprojekt


Abstract Focused on assisting mathematicians in constructing models of the HPA-axis, this report illustrates the regulating biological processes in the HPA-axis, under normal physiological conditions. The HPA-axis is the endocrine system, which controls the secretion of the stress hormone cortisol. The starting point of this project is a model initiated by Jelić et al. The model’s predictions of ACTH’s and cortisol’s oscillations, do not match with the experimentally achieved measurements. Regarding the dynamics of the HPA-axis, the three most essential hormones are CRH, ACTH and cortisol. These hormones undergo a complex interaction with each other. The main mechanism is that CRH stimulates the secretion of ACTH, which then stimulates the synthesis of cortisol that inhibits the production of both CRH and ACTH. Analysis of the above mentioned model indicates that the biological processes were imperfectly interpreted in the mathematical sense. Thus, it is emphasized that the hormones do not transform into each other as presumed, and cortisol’s feedback mechanism on the production and secretion of CRH and ACTH were incorrectly placed in the model. A compartment diagram is set up over the concentrations of CRH, ACTH and cortisol. The biological processes, which compose inflows and outflows of the compartments, are accounted for. Furthermore a suggestion is presented on how these processes can be converted into mathematical expressions.

UddannelserBasis - Naturvidenskabelig Bacheloruddannelse, (Bachelor uddannelse) Basis
Udgivelsesdato20 jun. 2008
VejledereCarsten Lunde Petersen


  • feedback
  • kompartmentdiagram
  • stress
  • matematik
  • kortisol
  • rate
  • ACTH
  • CRH
  • koncentration
  • HPA-aksen
  • sekretion
  • HPA-axis