Medicine and new technologies
The oral cavity is the first portion of the entire digestive tract. It is an irregularly shaped, elongated cavity, situated in the lower portion of the face, and its boundaries are partly bony and partly musculocutaneous. It is divided by the two rows of teeth into two incompletely separated spaces, the vestibulum oris and the oral cavity proper.
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The zygomatic [os zygomaticum] or malar bone forms the prominence known as the cheek and joins the zygomatic process of the temporal with the maxilla. It is quadrangular in form with the angles directed vertically and horizontally. The malar (or external) surface is convex and presents one or two small orifices for the transmission of the zygomatico-facial nerves and vessels. It is largely covered by the orbicularis oculi and near the middle is slightly ele- vated to form the malar tuberosity, which gives origin to the zygomaticus and zygomatic head of quadrate muscle of upper lip.
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As may be obvious from its name, one of the major functions of connective tissue is to connect tissues and organs. Unlike epithelial tissue, which is composed of cells closely packed with little or no extracellular space in between, connective tissue cells are dispersed in a matrix. The matrix usually includes a large amount of extracellular material produced by the connective tissue cells that are embedded within it.
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The mandible [mandibula] or lower jaw-bone is the largest and strongest bone of the face. It supports the mandibular teeth, and by means of a pair of condyles, moves on the skull at the mandibular fossae of the temporal bones. It consists of a horizontal portion — the body — strongly curved, so as to somewhat resemble in shape a horseshoe, from the ends of which two branches or rami ascend almost at right angles.
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Most epithelial tissues are essentially large sheets of cells covering all the surfaces of the body exposed to the outside world and lining the outside of organs. Epithelium also forms much of the glandular tissue of the body. Skin is not the only area of the body exposed to the outside. Other areas include the airways, the digestive tract, as well as the urinary and reproductive systems, all of which are lined by an epithelium. Hollow organs and body cavities that do not connect to the exterior of the body, which includes, blood vessels and serous membranes, are lined by endothelium (plural = endothelia), which is a type of epithelium.
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