Figure 1.

The ovarian follicle contains two main cellular compartments: the granulosa cell layer and the theca cell layer. These compartments are separated by the basal lamina such that blood vessels only contact the theca cells and release FSH there. Upon diffusion, FSH can influence the function of granulosa cells by binding their FSH receptors. FSH acts on granulosa cells to increase the activity of the non-neuronal cholinergic system of the ovarian follicle. Within this system, ACh acts through its muscarinic receptors to elevate intracellular calcium which leads to transcription factor changes, breakdown of gap junction communication, and activation of ion channels. Together, these actions promote growth in granulosa cells. AChE inactivates ACh and thereby limits its actions.