852
UNIT SIX
PRACTICE
34
What changes occur in a follicle and its oocyte during maturation?
35
What causes ovulation?
36
What happens to an oocyte following ovulation?
Female Internal Accessory Organs
The internal accessory organs of the female reproductive sys-
tem include a pair of uterine tubes, a uterus, and a vagina.
Uterine Tubes
The
uterine tubes
(fallopian tubes, or oviducts) are sus-
pended by portions of the broad ligament and open near the
ovaries. Each tube, about 10 centimeters long and 0.7 centi-
meters in diameter, passes medially to the uterus, penetrates
its wall, and opens into the uterine cavity.
Near each ovary, a uterine tube expands to form a
funnel-shaped
infundibulum
(in
fun-dib
u-lum), which
partially encircles the ovary medially. On its margin, the
infundibulum bears a number of irregular, branched exten-
sions called
±
mbriae
(F m
bre)
(f
g. 22.27)
. Although the
infundibulum generally does not touch the ovary, one of
the larger extensions (ovarian F
mbria) connects directly to
the ovary.
The wall of a uterine tube consists of an inner mucosal
layer, a middle muscular layer, and an outer covering of peri-
toneum. The mucosal layer is drawn into many longitudinal
After ovulation, the secondary oocyte and one or two
layers of follicular cells surrounding it are usually propelled
to the opening of a nearby uterine tube. If the secondary
oocyte is not fertilized within hours, it degenerates.
Figure
22.26
illustrates a conceptual progression of maturation of a
follicle over time and the release of an oocyte. In reality, the
secondary oocyte could be released from any external region
of the ovary and not directly into the uterine tube.
Follicular
scar (Corpus albicans)
Maturing
follicle
Germinal
epithelium
Primordial
follicles
Mature
follicle
Degenerating follicle
Blood vessel
Secondary
oocyte
Uterine tube
Ovary
FIGURE 22.25
Light micrograph of a follicle during ovulation (75×).
FIGURE 22.24
Light micrograph of a mammalian (monkey) ovary (30×). If ovulation does not occur, the follicle degenerates.
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