. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. Fig. 223. The profile of in- fancy. (After Bell.). Fig. 224. The mastication plane of a cow which makes it necessary to chew "up ; In the higher vertebrates the lips are two movable folds at the edge of the mouth aperture. They are covered by skin on the outside and moist mucous membrane on the inside. The red part of a lip, an exposed zone of transition between skin and mucous membrane in man, is extremely sensitive to touch because of an a
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. Fig. 223. The profile of in- fancy. (After Bell.). Fig. 224. The mastication plane of a cow which makes it necessary to chew "up ; In the higher vertebrates the lips are two movable folds at the edge of the mouth aperture. They are covered by skin on the outside and moist mucous membrane on the inside. The red part of a lip, an exposed zone of transition between skin and mucous membrane in man, is extremely sensitive to touch because of an abundant supply of nerve endings. The lower lip is more movable than the upper one. Attention to the form and shape of these portals to the digestive tube is shared alike by the compara- tive anatomist and the poet. 3. Buccal Cavity Immediately within the mouth aperture of mammals is the vestibule, or buccal cavity, bounded outwardly by the lips and cheeks, and inwardly by the external face of the teeth and gums. When the mouth is closed and the teeth are in contact, this cavity becomes practically obliterated, but behind the back teeth, and between the closed teeth, there is still direct communication with the larger oral cavity within. Various glands open inside the buccal cavity. Along the inner* surface of the lips are numerous small labial glatids that secrete mucus. These glands may be easily identified by rubbing the point of the tongue back and forth against the inner surface of the lips, when they will be felt as tiny bunches. Other mucus-producing glands, the molar glands, open from the cheeks. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Walter, Herbert Eugene, b. 1867; Sayles, Leonard Perkins, 1902-. New York : Macmillan Co.
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Keywords: ., bookcentury1900, booksubjectanatomycomparative, booksubjectverte
