Final answer:
Primary follicles start with a single layer of granulosa cells, but the granulosa cells then become active and transition from a flat or squamous shape to a rounded, cuboidal shape as they increase in size and proliferate. As the granulosa cells divide, the follicles-now called secondary follicles-increase in diameter, adding a new outer layer of connective tissue, blood vessels, and theca cells-cells that work with the granulosa cells to produce estrogens.
Step-by-step explanation:
After puberty, a few primordial follicles will respond to a recruitment signal each day, and will join a pool of immature growing follicles called primary follicles. Primary follicles start with a single layer of granulosa cells, but the granulosa cells then become active and transition from a flat or squamous shape to a rounded, cuboidal shape as they increase in size and proliferate.
As the granulosa cells divide, the follicles-now called secondary follicles-increase in diameter, adding a new outer layer of connective tissue, blood vessels, and theca cells-cells that work with the granulosa cells to produce estrogens.