Page 511 - Atlas of Histology with Functional Correlations

lined with a moist, stratified, squamous nonkeratinized oral epithelium (8) that

is thicker than the epithelium of the epidermis (11). The surface cells of the oral
epithelium (8), without cornification, are sloughed off (desquamated) into the
fluids of the mouth (10). Deeper connective tissue contains tubuloacinar and
mucus-secreting labial glands (9, 18). The secretions from these glands moisten
the oral mucosa. The small excretory ducts of the labial glands (9, 18) open into

the oral cavity.

The connective tissue of the lip also contains numerous adipose cells (7),
blood vessels (6), and numerous capillaries. Because the blood vessels (6) are
close to the surface, the color of the blood shows through the overlying thin

epithelium, giving the lips a characteristic red color.

FIGURE 13.5 ■ Lip (longitudinal section). Stain: hematoxylin and eosin. Low
magnification.

FIGURE 13.6 | Anterior Region of Tongue: Apex

(Longitudinal Section)

This illustration shows a longitudinal section of the anterior portion of the
tongue. The oral cavity is lined with a protective mucosa (5) that consists of an

outer epithelial layer (epithelium) (5a) and an underlying connective tissue
layer, the lamina propria (5b).

The dorsal surface of the tongue is rough due to numerous mucosal
projections called papillae (1, 2, 6). In contrast, the mucosa (5) of the ventral

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