Page 883 - Atlas of Histology with Functional Correlations

hormones, antibodies, gaseous products, and waste metabolites takes place as the

blood passes over the villi. Fetal blood enters the placenta through a pair of
umbilical arteries, passes into the villi, and returns through a single umbilical
vein.

MAMMARY GLANDS

The adult mammary gland is a compound tubuloalveolar gland that consists of
about 20 lobes connected to lactiferous ducts that open at the nipple. The lobes

are separated by connective tissue partitions and adipose tissue.

The resting or inactive mammary glands are small, consist of ducts, and do
not exhibit any developed or secretory alveoli. Inactive mammary glands also
exhibit slight cyclic alterations during the menstrual cycle. Under estrogenic
stimulation, the secretory cells increase in height, lumina appear in the ducts, and

a small amount of secretory material is accumulated.

Supplemental micrographic images are available at
www.thePoint.com/Eroschenko13e under Female Reproductive System.

FIGURE 21.29 | Cervix, Cervical Canal, and

Vaginal Fornix (Longitudinal Section)

The cervix is the lower part of the uterus. This figure illustrates a longitudinal

section through the cervix, the endocervix or cervical canal (5), a portion of the
vaginal fornix (8), and the vaginal wall (10).

The cervical canal (5) is lined with a tall, mucus-secreting simple columnar
epithelium (2) that is different from the uterine epithelium, with which it is
continuous. The cervical epithelium also lines the branched and tubular cervical

glands (3) that extend at an oblique angle to the cervical canal (5) into the
lamina propria (12). Some cervical glands may become occluded and develop
small glandular cysts (4). The connective tissue in the lamina propria (12) of the

cervix is more fibrous than in the uterus. Blood vessels, nerves, and occasional
lymphatic nodules (11) may be seen.

The lower end of the cervix, the os cervix (6), bulges into the vaginal canal
(13). The simple columnar epithelium (2) of the cervical canal (5) abruptly

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