T h e f e m a l e r e p r o d u c t i v e c y c l e • F i g u r e 1 6 . 1 1
The female reproductive cycle can last from 24 to 36 days; the average
is about 28 days. The preovulatory phase is more variable than other
phases. In this diagram, fertilization and implantation of the embryo
have not occurred. The inset shows the positive feedback that occurs
to produce the midcycle LH
surge.
High levels of
estrogens from
almost mature
follicle stimulate
release of more
GnRH and LH
t Hypothalamus
'C'
( GnRH promotes
release of FSH
LH and more LH
Anterior pituitary
a.
Hormonal regulation
o f
changes
in
the ovary
and
uterus
Ovary
GnRH
Almost mature
(graafian) follicle
11
Ovulated
secondary
■ F H \ oocyte
Corpus hemorrhagicum
(ruptured follicle)
Hypothalamus
O varian
cycle
Luteal phase
Corpus luteum
Uterine
(menstrual)
cycle
Endometrium
Days
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
1
2
Menstrual
Preovulatory
4
Postovulatory
phase
phase
Ovulation
phase
b. Changes in concentration of
anterior
pituitary and
ovarian
hormones
Menstrual phase
Preovulatory
(follicular) phase
Ovulation
Postovulatory
(luteal) phase
PROCESS DIAGRAM
previous page 518 Craig Freudenrich, Gerard J  Tortora   Visualizing Anatomy and Physiology   2011 read online next page 520 Craig Freudenrich, Gerard J  Tortora   Visualizing Anatomy and Physiology   2011 read online Home Toggle text on/off