28-17
From Puberty to Menopause
nDuring childhood
ovaries are inactive, and no follicles develop.
nAtresia occurs, in which
some primordial follicles regress or break
down.
nBy the time she
reaches puberty
only about 400,000 primordial follicles remain.
nAt puberty, the
hypothalamus releases GnRH (gonadotropin-releasing hormone), which stimulates the anterior
pituitary to release FSH (follicle-stimulating hormone) and LH (luteinizing hormone).
nThe levels of FSH and LH vary in a
cyclical pattern and produce a
monthly ovarian cycle.
nThe three phases of the ovarian cycle: are the follicular phase, ovulation,
and the luteal
phase.