The Digestive System.docx全文完整翻译.docx
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1、全文翻译IntroductionThe digestive or gastrointestinal tract (GI tract) begins with the mouth, where food enters the body, and ends with the anus, where solid waste material leaves the body.I It contains the organs involved in the ingestion and other components involved in the digestion of food. Theorgan
2、s known as the accessory digestive glands are the liver, gall bladder and pancreas, which aid in the processing of food and nutrients. Other components include the mouth. salivary glands, tongue, teeth and epiglottis. The primary functions of the digestive system are: ingestion, digestion, absorptio
3、n and elimination .消化道或胃肠道(GI tract)从食物进入身体的口腔开始,到固体废物离开身体的肛门结束。它包含了参与摄取的器官和其他参与消化食物的成分。被称为附属消化腺的器官是肝脏、胆囊和胰腺,它们帮助消化食物和营养物质。其他组成成分包括嘴,唾液腺,舌头,牙齿和会厌。消化系统的主要功能有:摄取、消化、吸收和消除。Anatomy and Physiology of Digestive System The TeethThe teeth are hard organs found along the anterior and lateral edges of the mou
4、th. Eachtooth is made of a bone-like substance called dentin and covered in a layer of enamel-the hardest substance in the body. The teeth are designed for cutting and grinding food into smaller pieces and are named after their particular roles in the process of mastication incisors for cutting or b
5、iting off pieces of food; canines for tearing; premolars and molars for chewing and grinding.消化系统的解剖学和生理学牙齿是位于口腔前部和外侧边缘的硬器官。每颗牙齿都是由一种叫做牙本质的类骨物质组成,表面覆盖着一层釉质人体最坚硬的物质。牙齿的设计是为了切割和研磨食物成更小的碎片,并根据它们在咀嚼过程中的特殊作用而命名:用于撕裂的犬齿;前臼齿和用于咀嚼和研磨的臼齿。The TongueThe tongue is located on the inferior portion of the mouth ju
6、st posterior and medial to the teeth. It is covered by many rough papillae for gripping food as it is moved by the tongues muscles. It also helps to push food toward the posterior part of the mouth for swallowing. 舌头位于口腔的下部,正好在牙齿的后部和内侧。它被许多粗糙的乳头覆盖,当它被舌头的肌肉移动时用来抓取食物。它也有助于把食物推向口腔后部吞咽。The PalateThe pal
7、ate is hard at the front of the mouth since the overlying mucosal is covering a plate of bone; being made of muscle and connective tissue, it is softer and more pliable at the back, and it can move to swallow food and liquids. The soft palate ends at the uvula. Posteriorly itis connected with the mu
8、cous membrane covering the floor of the nasal cavity.上颚在嘴的前部是坚硬的,因为上面的粘膜覆盖着一层骨头;它是由肌肉和结缔组织组成的, 背部更柔软、更柔韧,可以移动来吞咽食物和液体。软腭在小舌处结束。在后面,它与覆盖在鼻腔底部的粘膜相连。The Salivary GlandsThe salivary glands play an important role in the maintenance of dental health and general mouth lubrication. There are three pairs of
9、main salivary glands and between 800 and 1,000 minor salivary glands, all of which mainly serve the digestive process, without which speechwould be impossible.唾液腺在维护牙齿健康和一般口腔润滑方面起着重要作用。世界上有三对主要唾液腺和 800 到 1000 个次要唾液腺,它们主要用于消化过程,没有它们就不可能说话The EsophagusThe esophagus, a muscular tube connecting the phar
10、ynx to the stomach, carries swallowed masses of chewed food along its length, which is part of the upper GI tract. At the inferior end of the esophagus is a muscular ring called the lower esophageal sphincter or cardiac sphincter, the function of which is to close off the end of the esophagus and sq
11、ueeze food in the stomach.食道是连接咽部和胃的一根肌肉管,它是上消化道的一部分,沿着它的长度运送吞咽的大量咀嚼过的食物。在食道的下端有一肌肉环,称为食管下括约肌或贲门括约肌,其作用是关闭食道末端,挤压胃中的食物。The stomachThe stomach is a J-shaped organ joined to the esophagus at its upper end and to the duodenum at its lower end. In an average person, the stomach is about the size of thei
12、r two fists placed next to each other. It is divided into four sections: cardiac region, fundus, body or corpus and pyloric region. Gastric acid plays a vital role in the digestive process. As these chemicals would damage the stomach wall, mucus is secreted by innumerable gastric glands in the stoma
13、ch, to provide a slimy protective layer against the damaging effects of the chemicals. Meanwhile the protein is being digested, mechanical churning occurs through peristalsis, waves of muscular contractions that move along the stomach wall. This allows the mass of food to further mix with the digest
14、ive enzymes. The pylorus or pyloric region contains countless glands which secrete digestive enzymes including gastrin. After an hour or two of digestion, a thick semi-liquid called chyme is produced. When the pyloric sphincter, or valve opens, chyme enters the duodenum where it mixes further with d
15、igestive enzymes from the pancreas, and then passes through the small intestine, where digestion continues.胃是一个j 形的器官,其上端与食道相连,下端与十二指肠相连。一般人的胃大约是两个紧挨着的拳头的大小。它分为四个部分:幽门区,胃底,胃体和胃窦。胃酸在消化过程中起着至关重要的作用。由于这些化学物质会破坏胃壁,胃里无数的胃腺分泌粘液,以提供一层粘滑的保护层来抵御化学物质的破坏作用。与此同时,蛋白质正在被消化,通过胃壁的蠕动和肌肉收缩波发生机械搅动。这使得大量的食物进一步与消化酶混合。幽门
16、或幽门区含有无数腺体,它们分泌包括促胃液素在内的消化酶。经过一两个小时的消化,会产生一种叫做食糜的粘稠半液体。当幽门括约肌或瓣膜打开时,食糜进入十二指肠,与胰腺的消化酶进一步混合,然后通过小肠,继续消化。The Small IntestineThe small intestine is mainly responsible for absorption of the nutrients. The lower GI tract, including the small intestine and the large intestine, starts at the pyloric sphinct
17、er of the stomach and finishes at the anus. It is a long, thin tube about 3 cm in diameter and about 5 to 7 m long. It is located just inferior to the stomach and takes up most of the space in the abdominal cavity. The entire small intestine is coiled like a hose and the inside surface is full of ma
18、ny ridges and folds which are used to maximize the digestion of food and absorption of nutrients. When food leaves the small intestine, around 90% of all nutrients have been extracted. The small intestine is subdivided into the duodenum, the jejunum and the ileum. The duodenum, a hollow, jointed C-s
19、haped tube connecting the stomach to the jejunum, isthe first and shortest section of the small intestine.The jejunum contains circular folds,flaps of doubled mucosal membrane which partially and sometimes completely encircle the lumen of the intestine. These folds and villi serve to increase the su
20、rface area of the jejunum, enabling an increased absorption of digested sugars, amino acids and fatty acids into the bloodstream. The circular folds also slow the passage of food, giving more time for nutrients to be absorbed. The final, longest, and narrowest section of the small intestine is the i
21、leum. Its function is to absorb nutrients from food that has been digested in the stomach and the duodenum andthe jejunum.小肠主要负责吸收营养物质。下消化道,包括小肠和大肠,起于胃的幽门括约肌,止于肛门。它是一个长而细的管子,直径约 3 厘米,长约 5 至 7 米。它位于胃的下方,占据了腹腔的大部分空间。整个小肠像软管一样盘绕,内表面布满了许多脊和褶皱,用来最大限度地消化食物和吸收营养物质。当食物离开小肠时,大约 90%的营养物质被提取。小肠又细分为十二指肠、空肠和回肠。十
22、二指肠是连接胃和空肠的c 形中空管,是小肠的第一段,也是最短的一段。空肠有环状襞,双层粘膜瓣部分、部分或有时完全包围肠腔。这些褶皱和绒毛的作用是增加空肠的表面积,从而促进血液中糖、氨基酸和脂肪酸的吸收。这些环状襞也会减缓食物的流通速度,给营养物质更多的时间被吸收。小肠的最后、最长、最窄的部分是回肠。它的功能是从食物中吸收已经在胃、十二指肠和空肠消化的食物中吸收营养物质。The Large IntestineThe large intestine, a long, thick tube about 6 cm in diameter and about 1.5 m long, is located
23、 just inferior to the stomach and wraps around the superior and lateral border of the small intestine. It absorbs water and contains many symbiotic bacteria that aid in the breaking down of wastes to extract some small amounts of nutrients. It is divided into five parts: cecum,appendix, colon, rectu
24、m and anal canal. The cecum is a short, pouch-like region of the large intestine that descends from the union of the ileum and the large intestine.It assists inthe formation of feces: receiving chyme from the last part of the small intestine and connecting to the ascending colon of the large intesti
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