9-14. PRIMARY SEX ORGAN--OVARY
The ovary is the primary sex organ (gonad) of the female.
a. Location. Each female has a pair of ovaries, located in the pelvic cavity.
Each ovary is attached to the posterior aspect of the broad ligament on its respective
side of the uterus.
b. Production of the Ovum. One female gamete (ovum) is released per
menstrual cycle (about 28 days).
(1) Within an ovary, one of the germinal cells begins to develop and grows
larger as it stores food material. This development takes place within a follicle, a
fluid-filled cavity within the ovary.
(2) At midperiod, the mature ovum is expelled from the follicle onto the
surface of the ovary. The free ovum is picked up by the uterine tube. (para 9-15a).
c. Production of Female Sex Hormones. Initially, the cells of the ovary that
form the follicle secrete the hormones called estrogens. After the ovum has been
expelled from the follicle, the resulting cavity is filled with a yellowish material known as
the corpus luteum. The corpus luteum secretes primarily progesterone, a hormone that
helps prepare the uterus for pregnancy. Thus, estrogens are secreted during the first
half of the menstrual cycle, and progesterone is added during the second half of the
period. This pattern of hormone secretion is a major factor in the menstrual cycle.
9-15. SECONDARY SEX ORGANS
The secondary sex organs of the female serve to transport and care for the ovum
and to develop the new individual (embryo and fetus).
a. Uterine Tube (Oviduct, Fallopian Tube). The uterine tube picks up the free
ovum when it is expelled from the follicle of the ovary. The ovum stays in the uterine
tube to await fertilization. If it is fertilized, it goes through the initial stages of embryonic
development, and the embryo then passes on to the uterus. On the other hand, if it is
not fertilized, its stored food is exhausted in 3 to 5 days; it dies and its remains are
absorbed by the uterine tube.
b. Uterus. The uterus is a single pear-shaped organ located within the pelvic
cavity of the female. The early embryo passes into the uterus from the uterine tube.
The embryo continues its development within the uterus.
(1) Endometrium. The inner lining of the uterus is known as the
endometrium. The endometrium is an epithelium containing uterine glands and blood
vessels. Under the influence of the estrogens and progesterone, the embryo present at