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Mastication
Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, the food is positioned by the cheek and tongue between the teeth for grinding. The muscles of mastication move the jaws to bring the teeth into intermittent contact, repeatedly occluding and opening. As chewing continues, the food is made softer and warmer, and the enzymes in saliva begin to break down carbohydrates in the food. After chewing, the food (now called a bolus) is swallowed. It enters the esophagus and via peristalsis continues on to the stomach, where the next step of digestion occurs. Increasing the number of chews per bite increases relevant gut hormones. Studies suggest that chewing may decrease self-reported hunger and food intake. Chewing gum has been around for many centuries; there is evidence that northern Europeans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premastication
Premastication, pre-chewing, or kiss feeding is the act of chewing food for the purpose of physically breaking it down in order to feed another that is incapable of masticating the food by themselves. This is often done by the mother or relatives of a baby to produce baby food capable of being consumed by the child during the weaning process. The chewed food in the form of a bolus is transferred from the mouth of one individual to another, either directly mouth-to-mouth, via utensils, hands, or is further cooked or processed prior to feeding. The behaviour was common throughout human history and societies and observed in non-human animals. While premastication is less common in present-day Western societies, it was commonly practised, and is still done in more traditional cultures. Although the health benefits of premastication are still being actively studied, the practice appears to confer certain nutritional and immunological benefits to the infant, provided that the caretaker i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscles Of Mastication
There are four classical muscles of mastication. During mastication, three muscles of mastication (''musculi masticatorii'') are responsible for adduction of the jaw, and one (the lateral pterygoid) helps to abduct it. All four move the jaw laterally. Other muscles, usually associated with the hyoid, such as the mylohyoid muscle, are responsible for opening the jaw in addition to the lateral pterygoid. Structure The muscles are: * The masseter (composed of the superficial and deep head) * The temporalis (the sphenomandibularis is considered a part of the temporalis by some sources, and a distinct muscle by others) * The medial pterygoid * The lateral pterygoid In humans, the mandible, or lower jaw, is connected to the temporal bone of the skull via the temporomandibular joint. This is an extremely complex joint which permits movement in all planes. The muscles of mastication originate on the skull and insert into the mandible, thereby allowing for jaw movements during co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digestion
Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. Mechanical digestion takes place in the mouth through mastication and in the small intestine through segmentation contractions. In chemical digestion, enzymes break down food into the small molecules the body can use. In the human digestive system, food enters the mouth and mechanical digestion of the food starts by the action of mastication (chewing), a form of mechanical digestion, and the wetting contact o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporomandibular Joint
In anatomy, the temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilateral synovial articulation between the temporal bone of the skull above and the mandible below; it is from these bones that its name is derived. This joint is unique in that it is a bilateral joint that functions as one unit. Since the TMJ is connected to the mandible, the right and left joints must function together and therefore are not independent of each other. Structure The main components are the joint capsule, articular disc, mandibular condyles, articular surface of the temporal bone, temporomandibular ligament, stylomandibular ligament, sphenomandibular ligament, and lateral pterygoid muscle. Capsule The articular capsule (capsular ligament) is a thin, loose envelope, attached above to the circumference of the mandibular fossa and the articular tubercle immediately in front; below, to the neck of the condyle of the mandible. Its loose attachment t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occlusion (dentistry)
Occlusion, in a dental context, means simply the contact between teeth. More technically, it is the relationship between the maxillary (upper) and mandibular (lower) teeth when they approach each other, as occurs during chewing or at rest. Static occlusion refers to contact between teeth when the jaw is closed and stationary, while dynamic occlusion refers to occlusal contacts made when the jaw is moving. The masticatory system also involves the periodontium, the TMJ (and other skeletal components) and the neuromusculature, therefore the tooth contacts should not be looked at in isolation, but in relation to the overall masticatory system. Anatomy of Masticatory System One cannot fully understand occlusion without an in depth understanding of the anatomy including that of the teeth, TMJ, musculature surrounding this and the skeletal components. The Dentition and Surrounding Structures The human dentition consists of 32 permanent teeth and these are distributed betwee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chewing Gum
Chewing gum is a soft, cohesive substance designed to be chewed without being swallowed. Modern chewing gum is composed of gum base, sweeteners, softeners/ plasticizers, flavors, colors, and, typically, a hard or powdered polyol coating. Its texture is reminiscent of rubber because of the physical-chemical properties of its polymer, plasticizer, and resin components, which contribute to its elastic-plastic, sticky, chewy characteristics. History The cultural tradition of chewing gum seems to have developed through a convergent evolution process, as traces of this habit have arisen separately in many early civilizations. Each early precursor to chewing gum was derived from natural growths local to the region and was chewed purely out of the instinctual desire to masticate. Early chewers did not necessarily desire to derive nutritional benefits from their chewable substances but at times sought taste stimuli and teeth cleaning or breath-freshening capabilities. Chewing gum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teeth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tearing food, for defensive purposes, to intimidate other animals often including their own, or to carry prey or their young. The roots of teeth are covered by gums. Teeth are not made of bone, but rather of multiple tissues of varying density and hardness that originate from the embryonic germ layer, the ectoderm. The general structure of teeth is similar across the vertebrates, although there is considerable variation in their form and position. The teeth of mammals have deep roots, and this pattern is also found in some fish, and in crocodilians. In most teleost fish, however, the teeth are attached to the outer surface of the bone, while in lizards they are attached to the inner surface of the jaw by one side. In cartilaginous fish, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheek
The cheeks ( la, buccae) constitute the area of the face below the eyes and between the nose and the left or right ear. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve. The area between the inside of the cheek and the teeth and gums is called the vestibule or buccal pouch or buccal cavity and forms part of the mouth. In other animals the cheeks may also be referred to as jowls. Structure Humans Cheeks are fleshy in humans, the skin being suspended by the chin and the jaws, and forming the lateral wall of the human mouth, visibly touching the cheekbone below the eye. The inside of the cheek is lined with a mucous membrane (buccal mucosa, part of the oral mucosa). During mastication (chewing), the cheeks and tongue between them serve to keep the food between the teeth. Other animals The cheeks are covered externally by hairy skin, and internally by stratified squamous epithelium. This is mostly smooth, but may have caudally di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tongue
The tongue is a muscular organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive process, and is the primary organ of taste. The tongue's upper surface (dorsum) is covered by taste buds housed in numerous lingual papillae. It is sensitive and kept moist by saliva and is richly supplied with nerves and blood vessels. The tongue also serves as a natural means of cleaning the teeth. A major function of the tongue is the enabling of speech in humans and vocalization in other animals. The human tongue is divided into two parts, an oral part at the front and a pharyngeal part at the back. The left and right sides are also separated along most of its length by a vertical section of fibrous tissue (the lingual septum) that results in a groove, the median sulcus, on the tongue's surface. There are two groups of muscles of the tongue. The four intrinsic muscles alter the shape of the tongue and are not attached to bone. The f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapsid
Synapsids + (, 'arch') > () "having a fused arch"; synonymous with ''theropsids'' (Greek, "beast-face") are one of the two major groups of animals that evolved from basal amniotes, the other being the sauropsids, the group that includes reptiles and birds. The group includes mammals and every animal more closely related to mammals than to sauropsids. Unlike other amniotes, synapsids have a single temporal fenestra, an opening low in the skull roof behind each eye orbit, leaving a bony arch beneath each; this accounts for their name. The distinctive temporal fenestra developed about 318 million years ago during the Late Carboniferous period, when synapsids and sauropsids diverged, but was subsequently merged with the orbit in early mammals. Traditionally, non-mammalian synapsids were believed to have evolved from reptiles, and therefore described as mammal-like reptiles in classical systematics, and primitive synapsids were also referred to as pelycosaurs, or pelyc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comminution
Comminution is the reduction of solid materials from one average particle size to a smaller average particle size, by crushing, grinding, cutting, vibrating, or other processes. In geology, it occurs naturally during faulting in the upper part of the Earth's crust. In industry, it is an important unit operation in mineral processing, ceramics, electronics, and other fields, accomplished with many types of mill. In dentistry, it is the result of mastication of food. In general medicine, it is one of the most traumatic forms of bone fracture. Within industrial uses, the purpose of comminution is to reduce the size and to increase the surface area of solids. It is also used to free useful materials from matrix materials in which they are embedded, and to concentrate minerals. Energy requirements The comminution of solid materials consumes energy, which is being used to break up the solid into smaller pieces. The comminution energy can be estimated by: * Rittinger's law, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolus (digestion)
In digestion, a bolus (from Latin ''bolus'', "ball") is a ball-like mixture of food and saliva that forms in the mouth during the process of chewing (which is largely an adaptation for plant-eating mammals). It has the same color as the food being eaten, and the saliva gives it an alkaline pH. Under normal circumstances, the bolus is swallowed, and travels down the esophagus to the stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ... for digestion. See also * Chyme * Chyle References Digestive system {{Digestive-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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