13.36 小不小
Section outline
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These projections absorb. Absorb what?
::这些预测吸收了这些预测。Imagine the inside walls of the 23 feet of your small intestine covered with these finger-like projections. Why? What's their purpose, and why is the small intestine so long? These projections absorb. Absorb what? Minerals and nutrients from food . And the length of the small intestine allows as much of these important substances to be absorbed as possible.
::想象一下你小肠子的23英尺的墙壁 被这些手指般的预测所覆盖。 为什么? 它们的目的是什么? 为什么小肠子那么长? 这些预测吸收了。吸收了什么?矿物和食物的养分。小肠子的长度使得这些重要物质 尽可能多地被吸收。Digestion and Absorption: The Small Intestine
::消化和吸收:小不耐用The small intestine is a narrow tube about 7 meters (23 feet) long in adults. It is the site of most chemical digestion and virtually all absorption . The small intestine consists of three parts: the duodenum , jejunum and ileum .
::小型肠道在成人体内是一个大约7米(23英尺)的狭窄管子,是大部分化学消化和几乎全部吸收的场所,小肠道由三部分组成:二环、双环和二环。Digestion in the Small Intestine
::《小不适的消化》The duodenum is the first and shortest part of the small intestine. Most chemical digestion takes place here, and many digestive are active in the duodenum (see Table ). Some are produced by the duodenum itself. Others are produced by the pancreas and secreted into the duodenum.
::是小肠肠的第一个和最短的部分,大部分化学消化在这里进行,许多消化剂在二中很活跃(见表)。有些由二本身生产,另一些则由胰腺生产,并隐含在二中。Enzyme What It Digests Where It Is Made Amylase pancreas Trypsin pancreas Lipase pancreas, duodenum Maltase carbohydrates duodenum Peptidase proteins duodenum The liver is an organ of both digestion and excretion . It produces a fluid called bile , which is secreted into the duodenum. Some bile also goes to the gall bladder , a sac-like organ that stores and concentrates bile and then secretes it into the small intestine. In the duodenum, bile breaks up large globules of lipids into smaller globules that are easier for enzymes to break down. Bile also reduces the acidity of food entering from the highly acidic stomach . This is important because digestive enzymes that work in the duodenum need a neutral environment. The pancreas contributes to the neutral environment by secreting bicarbonate, a basic substance that neutralizes acid.
::肝脏是消化和排泄的器官。 它产生一种液体, 叫做胆碱, 它被隐藏在二角膜中。 一些胆碱也流入胆囊, 一种类似肉囊的器官, 储存和浓缩胆碱, 然后将它分解到小肠中。 在二角膜中, 胆碱将大量脂肪球球分解成小球球球, 使酶更容易分解。 胆碱还减少了从高酸性胃进食的食物的酸性。 这一点很重要, 因为在二角胃中工作的消化酶需要一个中立的环境。 胰腺通过分解双碳酸这一基本物质来帮助中立环境。Absorption in the Small Intestine
::吸附在小不适量中的吸附The jejunum is the second part of the small intestine, where most nutrients are absorbed into the . As shown in Figure , the mucous membrane lining the jejunum is covered with millions of microscopic, fingerlike projections called villi (singular, villus). Villi contain many capillaries, and nutrients pass from the villi into the bloodstream through the capillaries. Because there are so many villi, they greatly increase the surface area for absorption. In fact, they make the inner surface of the small intestine as large as a tennis court!
::jewunum 是小肠的第二部分, 大部分营养素都被吸收到肠中。 如图所示, Jejunum 内嵌的粘膜膜被数百万微小的、 指形的图象所覆盖。 Villi 含有许多毛毛, 以及从葡萄树到血管的血流中的营养素。 因为有这么多葡萄树, 它们大大增加了需要吸收的表面积。 事实上, 它们使小肠的内表像网球场一样大!This image shows intestinal villi greatly magnified. They are actually microscopic.
::此图像显示肠道阴道放大过大。 它们实际上是显微镜 。The ileum is the third part of the small intestine. A few remaining nutrients are absorbed here. Like the jejunum, the inner surface of the ileum is covered with villi that increase the surface area for absorption.
::是小肠的第三个部分。 这里吸收了剩下的几种营养素。 像jjununum一样, 的内表面被葡萄树覆盖, 增加了吸收的表面积 。Summary
::摘要-
Virtually all absorption of nutrients takes place in the small intestine, which has a very large inner surface area because it is covered with millions of microscopic villi.
::几乎所有养分的吸收都发生在小肠中,肠子的内表面积非常大,因为它覆盖着数百万微小的葡萄酒。
Review
::回顾-
Name the parts of the small intestine.
::命名小肠的部位。 -
Where are most nutrients absorbed?
::大多数养分被吸收到哪里去? -
What is digested by trypsin, by lipase, and by maltase?
::试探素、唇麻和麦芽能消化什么? -
Describe the functions of the three parts of the small intestine.
::描述小肠三部分的功能。 -
What role do villi play in absorption?
::葡萄酒在吸收方面起什么作用?
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Virtually all absorption of nutrients takes place in the small intestine, which has a very large inner surface area because it is covered with millions of microscopic villi.
