Page 885 - Atlas of Histology with Functional Correlations

canal. During the proliferative phase of the menstrual cycle, the secretion

from the cervical glands is thin and watery allowing for easier passage of
sperm from the vagina through the cervical canal into the uterus. However,
during the secretory (luteal) phase of the menstrual cycle and increased
progesterone secretions, as well as during pregnancy, the cervical gland
secretions change and become highly viscous, forming a mucus plug in the

cervical canal. The mucus plug hinders the further passage of additional
sperm and microorganisms from the vagina into the body of the uterus. Thus,
the cervical glands in the cervical canal perform an important protective

function initially in assisting the passage of sperm to fertilize the oocyte and
later in protecting the developing embryo in the uterus.

FIGURE 21.30 | Vagina (Longitudinal Section)

The vaginal mucosa is irregular with mucosal folds (1) and covered by
noncornified stratified squamous (2). The underlying connective tissue
papillae (3) are prominent and indent the epithelium.

The lamina propria (7) contains dense, irregular connective tissue with
elastic fibers that extend into the muscularis layer as interstitial fibers (10).

Diffuse lymphatic tissue (8), lymphatic nodules (4), and small blood vessels
(9) are in the lamina propria (7).

The muscularis of the vaginal wall consists predominantly of longitudinal
bundles (5a) and oblique bundles of smooth muscle (5). The transverse

bundles (5b) of the smooth muscle are less numerous but more frequently found
in the inner layers. The interstitial connective tissue (10) is rich in elastic fibers.
Blood vessels (11) and nerve bundles are abundant in the adventitia (6, 12).

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