(Greek: around, enclosing, surrounding, about, near, close; often used as a prefix)
2. Any mammal of the order Perissodactyla, comprising the odd-toed hoofed quadrupeds and including the tapirs, rhinoceroses, and horses.
The middle digit bears the weight of the body. These herbivorous mammals typically have feet encased in a protective horny hoof, lips adapted for plucking, strong cropping incisor teeth, and molars and premolars adapted for chewing.
The stomach is simple and bacterial digestion of cellulose occurs in the cecum, a blind pouch at the junction of the ileum and the colon.
Such herbivores rely on the activity of millions of symbiotic bacteria living in the cecum. These produce enzymes capable of digesting cellulose and releasing simple soluble substances that can be absorbed into the bloodstream.
2. A reference to the Perissodactyla (a division of ungulate, or hoofed, mammals, including those that have an odd number of toes, as the horse, tapir, and rhinoceros).
2. Etymology: from Greek, perissologos and from Latin perissologia, "speaking too much".
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2. The activity by which the alimentary canal and other tubular organs, that have both longitudinal and circular muscle fibers, propel their contents: The peristalsis consists of a wave of contractions passing along the tube for variable distances.
3. The wormlike motions by which the stomach and the bowels propel or send their contents: Peristalses consist of alternate waves of relaxations and contractions in successive parts of the intestinal tube and any obstructions to the flow of the contents will cause these contractions to become stronger and are often accompanied by a severe form of pain known as "colic" or an attack of spasmodic pain in the abdomen.
Food and digestion products are pushed through the intestine from the throat to the rectum, by peristalsis or the surging of muscular contractions of the intestinal wall.4. Etymology: from Greek peri, "around" + stalsis, "contraction".
The billowing peristaltic contractions of the alimentary canal, or any other tubular structures, result in the contents of such areas being forced onward toward a bodily opening.
Peristaltic movements are initiated by circular smooth muscles contracting behind the chewed food and drinking of liquids to prevent them from moving back into the mouth, which is then followed by a contraction of longitudinal smooth muscles which push the digested food onward.
Intestinal movements are not always the same.
When food is in the small intestine, the muscles that encircle the tube constrict about seven to twelve times a minute, segmenting the tube so it is similar to a series of sausages. These rapid contractions move the food back and forth, churning it, kneading or pressing it, and mixing it with the digestive juices.
Besides these mixing movements, the small intestine also makes propulsive, or peristaltic, movements: waves that move food through the system. In this part of the gastrointestinal tract, peristaltic movements are usually weak and infrequent.
These activities ensure that food will stay in one place long enough to be absorbed. Only when toxic substances enter the small intestine are the propulsive movements strong and quick, in order to expel the poisons as fast as possible.
In the stomach, the motions peristaltically blend food with gastric juices which turns them into a thin liquid.
The uvula is a small piece of soft tissue that can be seen dangling down from the soft palate over the back of the tongue. The uvula is described variously as being shaped like a U, a tear, or a grape.
2. Etymology: from the Latin word for "grape," uva.