Explore the ovarian and uterine cycles, investigate hormonal feedback, and apply your understanding to unfamiliar situations.
Move through a simplified 28-day reference cycle.
Illustrative, relative concentrations (not measured data)
The ovarian and uterine processes are synchronised with the graph.
Select a hormone to see where it is secreted, what it targets, and how it affects other hormones and reproductive structures.
Choose a scenario, read how it acts, then predict the effects on the hormones, ovary and uterus. Run the model day by day and compare it with a typical cycle.
Dashed: normal reference cycle (fully visible unless progressive reveal is selected). Solid: illustrative endogenous hormone response, drawn day by day. Externally administered medicines are described separately.
These structures follow the solid scenario curves. The dashed lines above remain the typical-cycle reference.
Run or advance the experiment to explain what is happening on each day.
Mechanism-based qualitative predictions, shown after the simulation.
Match each description to the correct hormone. The options may be used once.
For each answer, justify the timing using feedback mechanisms.
Sustained high oestradiol in the late follicular phase switches to positive feedback on the hypothalamic–pituitary axis, promoting an LH surge.
The corpus luteum forms from the ruptured follicle and secretes progesterone, maintaining the secretory endometrium.
In a non-pregnant cycle the corpus luteum regresses, progesterone and oestradiol fall, and endometrial support is lost.
Three IB-style interpretation questions. Choose an answer and check the explanation.
Practise moving from identification to mechanistic explanation.
Explain how changing oestradiol concentrations can both inhibit and stimulate LH secretion during a typical menstrual cycle.
Ask questions about hormones, feedback loops, ovarian events or the experiment you are exploring.