Part 1

Introduction Your body is simply amazing! It carries out countless different activities each day, such as walking, eating, and thinking—and many more without you even realizing it. Do you ever wonder why you don't forget to breathe? Or how many times your heart needs to pump each minute? Your body does this all for you on its own! All the body's organs work together, a little bit like an orchestra, to keep every part of you going strong. In this book, we'll take a closer look at the inner workings of the human body, and you'll discover how our understanding of the body has changed since ancient times. I hope you will come to appreciate just how unique and wonderful your body is! Dr. Bip Choudhury

引言 你的身体真的太奇妙啦！ 它每天都在进行数不清的活动，比如走路、吃饭、思考，还有好多你完全察觉不到的活动哦。 你有没有好奇过，为什么我们从来不会忘记呼吸？ 又或者，你的心脏一分钟要跳动多少次呢？ 这些事都是你的身体自己主动完成的哦！ 身体里所有器官一起协作，有点像交响乐团，让你全身上下都充满活力。 在这本书里，我们会仔细探索人体的内部运作，你还会发现，从古至今人类对身体的认知发生了怎样的变化。 我希望你能慢慢发觉，你的身体是多么独特、多么神奇呀！ 比普·乔杜里博士

Your amazing body Your body is an amazing machine, more complicated than a computer. It has a lot of different parts, some that you can see and many others that are hidden inside you. Body parts often come in pairs—this means you have a spare in case one gets damaged! What makes you, you? Although all bodies work in the same way, there is only one you. No one looks, thinks, or feels exactly like you. Many of your features are decided by your genes, but the experiences you have during your life also shape your appearance and personality. Each person has around 20,000 genes. Genes Each of your body's cells contains genes—a set of instructions that builds every part of you. You have two versions of each gene, one from your mother and one from your father. Your genes are unique to you, but twins that look the same share most of their genes. DNA Chromosomes are made of tightly coiled strands of a chemical called DNA. When unwound, DNA looks like a twisted ladder. Genes Sections of DNA are called genes. There are thousands of genes in each chromosome. Chromosomes There are 23 pairs of chromosomes in each cell. Half are from your mother and half from your father. Nucleus This is the instruction center of a cell. Your chromosomes, which contain your genes, are found every cell with a nucleus. Genetics Children look like their parents because of the genes they inherit from them. You inherit some genes from one parent and some from the other parent. This is why you might have eyes like your mother's but hair the same color as your father's. This child has inherited brown eyes from her father.

奇妙的身体 你的身体是一台神奇的机器，比电脑还要复杂呢。 它有好多不同的部分，有些你能看得见，还有好多藏在你的身体里。 身体的器官常常都是成对的——这样万一一个受伤了，还有另一个备用哦！ 是什么造就了独一无二的你？ 虽然所有人的身体运作方式都差不多，但你是独一无二的。 没有任何人的长相、想法和感受和你完全一样。 你的很多外貌特征都是基因决定的，但你一生的经历也会塑造你的外貌和性格哦。 每个人大约有两万个基因。 基因 你身体的每个细胞里都有基因——这是一套搭建你身体每一部分的指令哦。 每个基因都有两份，一份来自妈妈，一份来自爸爸。 你的基因只属于你自己，不过长得一模一样的双胞胎会共享大部分基因。 DNA 染色体是由一种叫做DNA的化学物质紧密缠绕而成的。 把它解开之后，DNA看起来就像一把扭转的梯子。 基因 DNA的片段就是基因。 每条染色体里都有成千上万个基因。 染色体 每个细胞里都有23对染色体。 一半来自妈妈，一半来自爸爸。 细胞核 它是细胞的指挥中心。 包含基因的染色体，存在于所有有细胞核的细胞里。 遗传学 孩子长得像父母，是因为他们继承了父母的基因。 你从爸爸那里继承一些基因，又从妈妈那里继承另一些基因。 所以你可能会长得像妈妈的眼睛，却有着和爸爸一样颜色的头发。 这个小女孩就继承了爸爸的棕色眼睛。

Groups of organs form organ systems. The mouth, throat, stomach, and intestines make up the digestive system, which takes energy and nutrients from the food you eat. Organs are composed of two or more tissues that work together to carry out a particular function. The stomach lining works with muscle tissue to digest food. Inside out Together, all the organ systems make one complete organism. Each part of the body, from a cell to a system, has to function properly to keep us healthy. Bone is a type of connective tissue—it connects different body parts. A lot of cells that do similar jobs combine to form tissues. The cells here are from the lining of the stomach and their job is to produce stomach acid. Red blood cell These cells have no nucleus and are a special shape so they can fit through vessels. White blood cell There are different types of white blood cells. They fight off infections. Fat cell Fat cells are found throughout the body and are an important store of energy. Muscle cell These cells make up muscles that contract and relax to help you move. Nerve cell Nerve cells send electrical messages around the body to tell it what to do. What are we made of? The smallest building block of the body is the cell. Groups of cells make tissues, which combine to make organs. All the organs put together form an organism, like you! Cells are held together by a skin, called a membrane. Inside is a soup-like liquid called cytoplasm in which organelles, or "mini organs," float around. The most important organelle is the nucleus—it contains instructions that tell the cell what to do.

不同的器官组合在一起就形成了器官系统。 嘴巴、喉咙、胃和肠道组成了消化系统，它会从你吃的食物中提取能量和营养。 器官由两种或更多组织组成，这些组织一起协作完成特定的功能。 胃粘膜和肌肉组织一起协作消化食物。 由内而外 所有的器官系统合在一起，就组成了一个完整的生命体。 身体的每一部分，小到细胞大到系统，都要正常工作才能让我们保持健康。 骨头是一种结缔组织——它用来连接身体不同的部位。 很多功能相似的细胞组合在一起就形成了组织。 这里展示的是胃粘膜的细胞，它们的工作是分泌胃酸。 红细胞 红细胞没有细胞核，形状很特殊，能穿过血管。 白细胞 白细胞分很多不同的种类。 它们负责抵抗感染。 脂肪细胞 脂肪细胞分布在全身，是重要的能量储存库。 肌肉细胞 这些细胞组成肌肉，肌肉通过收缩和舒张帮我们活动。 神经细胞 神经细胞会在全身传递电信号，指挥身体做出动作。 我们的身体是由什么组成的？ 身体最小的组成单位是细胞。 细胞组成组织，组织组合在一起形成器官。 所有器官组合在一起就形成了像你这样的生命体！ 细胞外面包裹着一层膜，叫做细胞膜。 细胞里面是汤一样的液体，叫做细胞质，细胞器也就是“迷你器官”就漂浮在里面。 最重要的细胞器是细胞核——它包含着指挥细胞工作的指令。

Body systems Organ systems are groups of organs that work together to do a particular job. Our bodies have a lot of organ systems and some of the most important ones are shown here. Musculoskeletal system The musculosketetal system is made up of muscles attached to bones. Together, they help us move. Muscles are stretchy, while bones are very hard. Nervous system The brain, spinal cord, and nerves make up the nervous sytem. The brain stores memories and sends out instructions. The spinal cord and nerves carry messages between the brain and the whole body. Respiratory system This system is made up of the lungs and airways. It helps us breathe in air full of oxygen and gets rid of the waste gas carbon dioxide. Other body systems There are several more organ systems not shown here. These include the renal system, which makes urine, and the immune system, which fights infections. Every organ is made from cells a little like me! Cardiovascular system The cardiovascular system is made up of the heart and blood vessels. One of its main functions is to supply all parts of the body with oxygen, which is carried by red blood cells. Digestive system This system starts at the mouth and ends at the anus. Its job is to digest food so that the body has plenty of energy. Strong teeth start the process by breaking down food. Reproductive system Babies wouldn't be born without this system. Male reproductive organs make sperm, and female organs make eggs. These join together inside the woman's uterus, where the baby grows.

身体系统 器官系统是由多个器官组合而成，它们会一起完成特定工作。 我们的身体有很多器官系统，这里展示了其中最重要的几种。 肌肉骨骼系统 肌肉骨骼系统由附着在骨骼上的肌肉组成。 它们一起协作，帮助我们活动身体。 肌肉富有弹性，而骨骼十分坚硬。 神经系统 神经系统由大脑、脊髓和神经组成。 大脑储存记忆，还会发出行动指令。 脊髓和神经负责在大脑和全身之间传递信息。 呼吸系统 呼吸系统由肺和呼吸道组成。 它帮助我们吸入富含氧气的空气，排出废气二氧化碳。 其他身体系统 还有不少器官系统没有在这里展示。 其中包括生成尿液的肾脏系统，还有对抗感染的免疫系统。 每一个器官都由细胞组成，就像我一样哦！ 心血管系统 心血管系统由心脏和血管组成。 它的主要功能之一，是给全身各处输送红细胞携带的氧气。 消化系统 消化系统从口腔开始，到肛门结束。 它的工作是消化食物，给身体提供充足的能量。 坚固的牙齿会先分解食物，开启消化过程。 生殖系统 没有这个系统就没法诞生小宝宝啦。 男性生殖器官产生精子，女性生殖器官产生卵子。 它们会在女性的子宫中结合，小宝宝就在这里生长。

Your super skeleton Your skeleton acts as a frame for your body—it keeps everything together and your muscles attach to it. The bones in your skeleton are strong and some protect your organs. Joints A joint is formed where two or more bones meet. The bones are held together by tough tissues called ligaments. Joints let us bend, stretch, and dance! A joint that can move in almost any direction, such as the hip joint, looks like a ball in a socket. The funny bone is not a bone at all— it's a nerve behind your elbow. Cartilage A flexible tissue called cartilage is found where bones meet, protecting their surface to stop it from wearing away. Your ears and the front of your nose are also made of cartilage. That is why they feel a little bendable. Inside the bone The outside of a bone is hard, but the inside is soft, spongy, and full of holes—this makes it light. Bones are filled with a jelly-like substance called bone marrow, and the holes contain many blood vessels and nerves. X-RAYS X-ray images help doctors to see if bones are healthy. The "X" in X-ray stands for "unknown" because X-rays were discovered by accident! Broken bones Bones are so dense, or solid, that they appear white on an X-ray image. Can you spot the broken bone in this X-ray? Some bones are stronger than concrete!

超级骨架 你的骨架是身体的支架——它把所有组织器官固定在一起，肌肉也附着在它上面。 骨架里的骨头十分坚固，有些骨头还能保护我们的内脏器官。 关节 两块或多块骨头连接的位置就形成了关节。 坚韧的韧带组织把骨头牢牢连接在一起。 关节让我们可以弯腰、伸展，还能跳舞呀！ 像髋关节这样能向几乎所有方向活动的关节，结构就像球嵌在凹槽里。 麻筋根本不是骨头——它是手肘后方的一根神经哦。 软骨 骨头连接处有一种柔软有弹性的组织叫软骨，它能保护骨头表面，防止磨损。 你的耳朵和鼻子前端也是由软骨组成的。 所以你摸起来会觉得它们有点软，还可以弯曲哦。 骨头内部 骨头的外壳很硬，但内部柔软疏松、布满孔洞——这让骨头变得很轻。 骨头里充满了果冻状的物质，叫做骨髓，孔洞里还有很多血管和神经。 X光 X光片能帮医生判断骨头是否健康。 X光里的“X”代表“未知”，因为X光是偶然被发现的哦！ 骨折 骨头密度高、质地密实，所以在X光片上会呈现白色。 你能在这张X光片里找出断掉的骨头吗？ 有些骨头比混凝土还要结实哦！