Time: the axis counts elapsed model days. Model day 0 is the start of bleeding (clinical cycle day 1). Mid-cycle ovulation and the 28-day duration are examples; human timing varies.

Read the pattern: each hormone has its own relative scale. Heights cannot compare concentrations between hormones. Solid curves show the selected condition; dashed comparison curves show the condition named in the legend. GnRH ticks are schematic, not measured pulse timing.

Scope: this model simplifies dominant-follicle development, sustained estradiol feedback, luteal regression, and endometrial responses. Inhibin selectively reduces FSH in the body but is not simulated separately. Pill inputs represent hormone activity, not measured estradiol/progesterone concentrations. Pregnancy covers early corpus luteum support, before the placental takeover.