Ebook Ganong''s review of medical physiology (25th edition): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Ganong''s review of medical physiology (25th edition): Part 2
Ebook Ganong''s review of medical physiology (25th edition): Part 2
SECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirements Ebook Ganong''s review of medical physiology (25th edition): Part 2s simply with the activity of membrane transport proteins that permit the uptake of specific molecules into the cytosol. However, for multicellular organisms, including humans, the challenges of delivering nutrients to appropriate sites in the body are significantly greater, particularly if the orga Ebook Ganong''s review of medical physiology (25th edition): Part 2nisms are terrestrial. Further, most of the food we eat is in the form of macromolecules, and even when these are digested to their component monomersEbook Ganong''s review of medical physiology (25th edition): Part 2
, most of the end products are water-soluble and do not readily cross cell membranes (a notable exception are the constituents of dietary lipids). ThuSECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirements Ebook Ganong''s review of medical physiology (25th edition): Part 2substances (toxins and microbial products, as well as microbes themselves). The latter situation is complicated by the fact that the intestine maintains a lifelong relationship with a rich microbial ecosystem residing in its lumen, a relationship that is largely mutually beneficial if the microbes a Ebook Ganong''s review of medical physiology (25th edition): Part 2re excluded from the systemic compartment.The intestine is a continuous tube that extends from mouth to anus and is formally contiguous with the exterEbook Ganong''s review of medical physiology (25th edition): Part 2
nal environment. A single cell layer of columnar epithelial cells comprises the scmipcrmeablc barrier across which controlled uptake of nutrients takeSECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirements Ebook Ganong''s review of medical physiology (25th edition): Part 2g to distal segments, and regulation of the microbiota. There are also important motility functions that move the intestinal contents and resulting waste products along the length of the gut, and a rich Innervation that regulates motility, secretion and nutrient uptake, in many cases in a manner tha Ebook Ganong''s review of medical physiology (25th edition): Part 2t is independent of the central nervous system. There is also a large number of endocrine cells that release hormones that work together with neurotraEbook Ganong''s review of medical physiology (25th edition): Part 2
nsmitters to coordinate overall regulation of the gastrointestinal system. In general, there is a considerable redundancy of control systems as well aSECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirements Ebook Ganong''s review of medical physiology (25th edition): Part 2he modern epi demic of obesity.The liver, while playing important roles in whole body metabolism, is usually considered a part of the gastrointestinal system for two main reasons. First, it provides for excretion from the body of lipid-soluble waste products that cannot enter the urine. These are se Ebook Ganong''s review of medical physiology (25th edition): Part 2creted into the bile and thence into the intestine to be excreted with the feces. Second, the blood flow draining the intestine is arranged such thatEbook Ganong''s review of medical physiology (25th edition): Part 2
substances that arc absorbed pass first through the liver, allowing for the removal and metabolism of any toxins that have inadvertently been taken upSECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirements Ebook Ganong''s review of medical physiology (25th edition): Part 2er will be considered, and the ways in which the various segments communicate to provide an integrated response to a mixed meal (proteins, carbohydrates, and lipids). The relevance of gastrointestinal physiology for the development of digestive diseases will also be considered. While many arc rarely Ebook Ganong''s review of medical physiology (25th edition): Part 2 life-threatening (with some notable exceptions, such as specific cancers) digestive diseases represent a substantial burden in terms of morbidity andEbook Ganong''s review of medical physiology (25th edition): Part 2
lost productivity. A 2009 report of the US National Institutes of Diabetes, Digestive and Kidney Diseases found that on an annual basis, for every toSECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirements Ebook Ganong''s review of medical physiology (25th edition): Part 2ses also appear to be increasing In this population (although mortality, principally from cancers, is thankfully In decline). On the other hand, digestive diseases, and In particular infectious diarrhea, remain important causes of mortality in developing countries where clean sources of food and wat Ebook Ganong''s review of medical physiology (25th edition): Part 2er cannot be assured. In any event, the burden of digestive diseases provides an Important Impetus for gaining a full understanding of gastrointestinaEbook Ganong''s review of medical physiology (25th edition): Part 2
l physiology, since it is a failure of such physiology that most often leads to disease. Conversely, an understanding of specific digestive conditionsSECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirements Ebook Ganong''s review of medical physiology (25th edition): Part 2ying this chapter, you should be able to:CHAPTER25■Understand the functional significance of the gastrointestinal system, and in particular, its roles in nutrient assimilation, excretion, and immunity.■Describe the structure of the gastrointestinal tract, the glands that drain into it, and its subdi Ebook Ganong''s review of medical physiology (25th edition): Part 2vision into functional segments.■List the major gastrointestinal secretions, their components, and the stimuli that regulate their production.■DescribEbook Ganong''s review of medical physiology (25th edition): Part 2
e water balance in the gastrointestinal tract and explain how the level of luminal fluidity is adjusted to allow for digestion and absorption.■IdentifSECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirements Ebook Ganong''s review of medical physiology (25th edition): Part 2ystem and the splanchnic circulation.INTRODUCTIONThe primary function of the gastrointestinal tract is to serve as a portal whereby nutrients and waler can be absorbed into the body. In fulfilling this function, the meal is mixed with a variety of secretions that arise from both the gastrointestinal Ebook Ganong''s review of medical physiology (25th edition): Part 2 tract itself and organs that drain into it, such as the pancreas, gallbladder, and salivary glands. Likewise, the intestine displays a variety of motEbook Ganong''s review of medical physiology (25th edition): Part 2
ility patterns that serve to mix the meal with digestive secretions and move it along the lengthof the gastrointestinal tract. Ultimately, residues ofSECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirements Ebook Ganong''s review of medical physiology (25th edition): Part 2th the ingestion of meals. Thus, the gastrointestinal system has evolved a large number of regulatory mechanisms that act both locally and over long distances to coordinate the function of the gut and the organs that drain into It.STRUCTURAL CONSIDERATIONSThe parts of the gastrointestinal tract that Ebook Ganong''s review of medical physiology (25th edition): Part 2 are encoun tered by the meal or its residues include, in order, the mouth, esophagus, stomach, duodenum, jejunum, ileum, cecum, colon, rectum, and anEbook Ganong''s review of medical physiology (25th edition): Part 2
us. Throughout the length of the intestine, glandular structures deliver secretions into the lumen, particularly in the stomach and mouth. Also importSECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirements Ebook Ganong''s review of medical physiology (25th edition): Part 2 surface area, which is important for its absorptive function. The intestinal tractis functionally divided into segments by means of muscle rings known as sphincters, which restrict the flow of intes final contents to optimize digestion and absorption. These sphincters include the upper and lower es Ebook Ganong''s review of medical physiology (25th edition): Part 2ophageal sphincters, the pylorus that retards emptying of the stomach, the ileocecal valve that retains colonic contents (including large numbers of bEbook Ganong''s review of medical physiology (25th edition): Part 2
acteria) in the large intestine, and the inner and outer anal sphincters. After toilet training, the latter permits delaying the elimination of wastesSECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirements Ebook Ganong''s review of medical physiology (25th edition): Part 2454 SECTION IV Gasvointwtirwl PhysiologyEpithetauinBasement membraneLamina propriaMuscUaris mucosaSubmucosaCircular muscleMyenteric plexusLongitudinal muscle Ebook Ganong''s review of medical physiology (25th edition): Part 2SECTION IV I Gastrointestinal PhysiologyFor unicellular organisms that exist in a sea of nutrients, it is possible to satisfy nutritional requirementsGọi ngay
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