palate

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palate

(păl`ĭt), roof of the mouth. The front part, known as the hard palate, formed by the upper maxillary bones and the palatine bones, separates the mouth from the nasal cavity. It is composed of a bone plate covered with a layer of mucous membrane tissue. The back portion, or soft palate, consists of muscular tissue and mucous membrane forming a partial partition between the mouth and the throat. A small conelike projection, the uvula, hangs from the middle of the soft palate in humans. The soft palate and uvula move upward during swallowing or sucking, preventing food from entering the nasopharynx. In mammals other than humans, the soft palate overlaps the larynx during swallowing so as to prevent entry of foreign substances into the respiratory tract. Both the hard and soft portions of the palate are lined with mucous membrane containing numerous glands that lubricate the mouth and throat. If the sides of the bony palate fail to come together during embryonic development an opening, or cleft, remains along the midline. This condition, known as cleft palate, can be repaired surgically in early infancy. See digestive systemdigestive system,
in the animal kingdom, a group of organs functioning in digestion and assimilation of food and elimination of wastes. Virtually all animals have a digestive system. In the vertebrates (phylum Chordata, subphylum Vertebrata) the digestive system is very complex.
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Palate

 

the roof of the oral cavity in vertebrate animals and man.

In petromyzons, Myxine, and cartilaginous fish, the palate is formed from the base of the chondrocranium; in bony fish and terrestrial vertebrates with secondary jaws, it is formed from the bones that originate in the base of the skull and at the site of the palatoquadrate cartilage. In some fish (Dipnoi and Crossop-terygii) and terrestrial vertebrates, the anterior section of the palate has primary choanae, or internal nares. In a number of reptiles (Testudinata, crocodiles, and Pelycosauria) and in mammals, there is a secondary hard palate, formed from the membrane bones; it divides the oral cavity from the nasopharyngeal passages, which open into the pharynx through the secondary choanae. The secondary palate in reptiles and mammals prevents the entry of food into the air passages and the disruption of breathing; in crocodiles it facilitates normal respiration when food is captured in the water. The appearance of a secondary bony palate in mammals strengthened the posterior sections of the upper jaw, which was one of the conditions for the development of true molars. The hard palate in mammals gradually develops into the muscular membrane known as the soft palate, which delineates the fauces—the opening into the pharynx—superiorly and laterally.

In man the palate is a solid membrane that divides the oral and nasal cavities. It consists of the bony palate (part of the skeleton of the facial cranium), which is covered with a mucous membrane on each side of the cavities. The bony palate is formed from the palatine processes of the left and right maxillae and the horizontal membranes of the palatine bones, which are united by the sagittal and transverse sutures. The superior surface of the hard palate is almost flat—it serves as the floor of the nasal cavity; the inferior surface of the hard palate faces the oral cavity and has a concave, domelike shape. The soft palate, which consists of mucous membrane with submucosal tissue and a muscular layer with fatty tissue, is a continuation posteriorly of the hard palate. The mucous membrane on the side of the oral cavity is lined with multilayered epithelium, and on the side of the nasal cavity with ciliated epithelium. The hard and soft palates together constitute the superior wall of the oral cavity.

When there is disturbance of embryo formation, defects in the development of the palate may arise, including cleft palate.

REFERENCE

Kudrin, I. S. Anatomiia organov polosti rta. Moscow, 1968.

palate

[′pal·ət]
(anatomy)
The roof of the mouth.

palate

1. the roof of the mouth, separating the oral and nasal cavities
2. Botany (in some two-lipped corollas) the projecting part of the lower lip that closes the opening of the corolla
References in periodicals archive ?
In all categories of cleft male dominance is observed except a complete cleft of the secondary palate as showed in Table 2.
Ocurrance and temporal variation in matrix metalloproteinases and their inhibitors during murine secondary palate morphogenesis.
They considered to be a palygenic multifactorial problem in which genetic susceptibility is influenced by multiple and probably cumulative environmental factors, interacting altogether to shift the complex process of morphogenesis of the primary and secondary palates, toward a threshold of abnormality at which clefting may occur (multifactorial/threshold model).
Clefting of the secondary palate only includes all structures posterior to the incisive foramen.
(1) It is classically characterized by clefting of the secondary palate, cardiac defects, learning disabilities, and facial dysmorphism.
Several other events in skeletal morphogenesis were examined, including differentiation of cartilage in the basioccipital-basisphenoid region, closure of the secondary palate, first appearance of tooth buds, the differentiation of the malleus and incus at the posterior region of Meckel's cartilage, the differentiation of secondary cartilage on the mandibular condyle, and the development of a joint capsule at the dentary-squamosal joint.
OBJECTIVES: We used a genetic approach to understand the interaction between atRA and dioxin and to identify the cell type targeted by dioxin toxicity during secondary palate formation in mice.
Differences in extracellular matrix components and cell density during normal and dexamethasone-treated secondary palate development in two strains of mice with different susceptibility to glucocorticoid-induced clefting.
The nasal cavity of gorgonopsians is much larger than in dicynodonts, but like pelycosaurs and other primitive therapsids, they lack a bony secondary palate. Some authors suggested that a membranous secondary palate may have existed in gorgonopsians (Watson 1921; Kermack 1956; Tatarinov 1963; Kemp 1982), others considered this unlikely (Kemp 1969; Sigogneau-Russell 1989).
Clinical examination revealed an otherwise normal baby weighing 3 kg with a tubular fleshy structure measuring about 3 cm in the medial canthus of the left eye and cleft of the left upper lip, alveolus, and primary and secondary palates (Figure 1).
In complete cleft lip and palate patients, the bony defect involves both the primary and secondary palates. There are three major methods for the closure of the cleft alveolus: primary bone grafting during the primary nasal and lip closure (approximately 5 months of age), secondary bone grafting (before the eruption of maxillary permanent canines, approximately 9-11 years of age), and GPP.
The distribution of clefts of the primary and secondary palates by sex, type, and location.