How Your Body Digests Food身体如何消化食物

I-13 / 013

How Your Body Digests Food

People in different parts of the earth eat different kinds of food. No matter what people eat, people all over the world grow. All people need food to make them grow.

How does the food you eat turn into the things that your body needs to make you grow big and strong?

Food Comes into the Mouth

Think what it would be like if you went home after school and the smell of fresh cookies reached your nostrils. Would your mouth water?

That water-like matter is called saliva. Saliva comes from glands inside your mouth. These glands (salivary glands) are on each side of your cheek and under your tongue.

When you start to chew a cookie, the saliva makes your cookie soft. Your tongue throws the cookie around, mixing it with the saliva. You are beginning to digest your cookie.

When the cookie is soft enough, your tongue throws the cookie to the back of your mouth. A little door closes off the windpipe so that the food will not go into your windpipe.

Food Goes to the Stomach

The food goes down a long tube to your stomach. On the inside of your stomach are some very strong muscles. These strong muscles break up the food for several hours. The stomach breaks up the food until it gets soupy.

The stomach then pushes the food into the small intestine. The small intestine is a long tube. The curly tube is about three times the length of your body. More digestion takes place here.

Food is Ready for the Body

The same sort of thing happens in your intestine. Food that is ready for the body can pass through the walls of the small intestine. The rest of the food is held back until it is ready to go to the blood, or is pushed out of the body as waste.

The blood takes the food to muscles, bones, and other parts of your body. The food makes your body strong to work, run and play. It keeps you growing and changing. The food which the body cannot use is pushed into the large intestine and out of your body.

必背词汇

练 习

1. Study the picture. Find the salivary gland, the stomach, the throat, the food tube, the small intestine, and the large intestine.

2. Answer the questions. Use good sentences.

(1) What takes the food to all parts of the body? ___________________________

(2) What does the food become that the body cannot use?___________________

(3) What happens in the small intestine?__________________________________

译 文

身体如何消化食物

在地球上，不同地方的人吃不同的食物。但不管吃什么，全世界的人都在生长，都需要食物来满足生长需求。

你们所吃的食物是如何转变成身体所需的物质，从而使你们长得高大强壮呢？

食物入口

想象一下，放学回家，闻到刚烤好的饼干的香味，你会有何反应？会流口水吗？

那种水状的物质称为唾液。唾液来自口中的腺体，这些腺体（唾液腺）分布在脸颊两侧及舌头下方。

当你开始咀嚼饼干时，唾液会使饼干变软。舌头来回搅动，使饼干与唾液混合，这时你就开始消化饼干了。

当饼干变得足够松软，舌头便将饼干送至嘴部后方。此处有一扇横挡在气管口的小门，使食物不会进入气管。

食物入胃

食物经过一段长长的管道才会进入胃中。胃的内侧是一些强健的肌肉，这些强健的肌肉会花上数小时来磨碎食物，直到食物呈汤状。

然后，胃会把食物送入小肠。小肠是一条长长的管道，这条弯曲管道的长度是你身体的三倍，食物在这里进行更进一步的消化。

食物准备吸收

同样的消化过程也会在肠内进行。为身体准备好的食物会被小肠壁所吸收。剩下的食物则被阻挡，直到能够进入血液为止，或作为排泄物被排出体外。

血液将食物带到肌肉、骨骼及身体的其他部分。这些食物使你的身体变得强壮，从而能够工作、跑步及玩耍。它促使你不断成长、变化。不能被吸收的食物则被送进大肠，排出体外。

练 习

1. 研究图片。找出唾液腺、胃、喉、食道、小肠及大肠。

2. 用完整的句子回答问题。

(1) 什么把食物送到身体的各个部位？

(2) 身体不能吸收的食物变成了什么？

(3) 小肠进行了哪些活动？

答 案

1. (1) salivary gland (2) throat (3) food tube (4) stomach

(5) large intestine (6) small intestive

2. (1) The blood takes the food to muscles, bones, and other parts of your body

(2) The rest of the food is held back until it is ready to go to the blood, or is pushed out of the body as waste.

(3) More digestion takes place here.