What is homeostasis? How is the human body organized? What are the 11 different human organ systems?

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1 CHAPTER 22 1 Body Organization SECTION Body Organization and Structure BEFORE YOU READ After you read this section, you should be able to answer these questions: What is homeostasis? How is the human body organized? What are the 11 different human organ systems? National Science Education Standards LS 1a, 1d, 3a How Is the Body Organized? The different parts of your body all work together to maintain, or keep, the conditions in your body stable. Your body works to keep itself stable even when things outside your body change. This is called homeostasis. For example, your body temperature needs to stay the same even when temperatures outside are very cold or very hot. If your body could not keep its inside conditions the same, many processes in your body would not work. Conditions inside and outside your body are always changing. Your body can maintain homeostasis because each cell does not have to do everything your body needs. Instead, your body is organized into different levels. The parts at each level work together to help your body maintain homeostasis. There are four levels of organization in the body: cells, tissues, organs, and organ systems. Cells are the smallest level of organization. A group of similar cells working together forms a tissue. Your body has four main kinds of tissue: epithelial, nervous, muscle, and connective. Four Kinds of Tissue STUDY TIP Discuss Read this section silently. When you finish reading, work with a partner to answer any questions you may have about the section. STANDARDS CHECK LS 3a All organisms must be able to obtain and use resources, grow, reproduce, and maintain stable internal conditions while living in a constantly changing external environment. Word Help: resource anything that can be used to take care of a need Word Help: environment the surrounding natural conditions that affect an organism Epithelial tissue covers and protects other tissues. Nervous tissue sends electrical signals through the body. 1. Define What is homeostasis? Muscle tissue is made of cells that contract and relax to produce movement. Connective tissue joins, supports, protects, insulates, nourishes, and cushions organs. It also keeps organs from falling apart. Interactive Textbook 349 Body Organization and Structure

SECTION 1 Body Organization continued READING CHECK 2. Define What is an organ? ORGANS When different kinds of tissues work together, they can do more than any one tissue can do alone.

2 SECTION 1 Body Organization continued READING CHECK 2. Define What is an organ? ORGANS When different kinds of tissues work together, they can do more than any one tissue can do alone. A group of two or more tissues working together to do a job is an organ. For example, your stomach is an organ that helps you digest your food. None of the stomach s tissues could digest food alone. Four Kinds of Tissue in the Stomach Nervous tissue helps control all the movements of the stomach. Blood is a connective tissue found in the wall of the stomach. Epithelial tissue lines the stomach. Muscle tissue mixes food and stomach acids. Critical Thinking 3. Apply Concepts How does the stomach work as part of an organ system? ORGAN SYSTEMS Organs that work together to do a job make up an organ system. For example, your stomach works with other organs in the digestive system, such as the intestines, to digest food. Organ systems can do jobs that one organ alone cannot do. Each organ system has a special function. There are 11 different organ systems that make up the human body. No organ system works alone. For example, the respiratory system and cardiovascular system work together to move oxygen through your body. Integumentary System Your skin, hair, and nails protect the tissue that lies beneath them. Muscular System Your muscular system works with the skeletal system to help you move. Skeletal System Your bones provide a frame to support and protect your body parts. Interactive Textbook 350 Body Organization and Structure

SECTION 1 Body Organization continued Cardiovascular System Your heart pumps blood through all of your blood vessels. Respiratory System Your lungs absorb oxygen and release carbon dioxide.

Male Reproductive System The male reproductive system produces and delivers sperm. Female Reproductive System The female reproductive system produces eggs and nourishes and protects the fetus.

Digestive System Your digestive system breaks down the food you eat into nutrients that your body can absorb.

3 SECTION 1 Body Organization continued Cardiovascular System Your heart pumps blood through all of your blood vessels. Respiratory System Your lungs absorb oxygen and release carbon dioxide. Urinary System Your urinary system removes wastes from the blood and regulates your body s fluids. TAKE A LOOK 4. Identify Which organ system includes your lungs? Male Reproductive System The male reproductive system produces and delivers sperm. Female Reproductive System The female reproductive system produces eggs and nourishes and protects the fetus. Nervous System Your nervous system receives and sends electrical messages throughout your body. 5. Identify Which organ system is different in males and females? Digestive System Your digestive system breaks down the food you eat into nutrients that your body can absorb. Lymphatic System The lymphatic system returns leaked fluids to blood vessels and helps get rid of bacteria and viruses. Endocrine System Your glands send out chemical messages. Ovaries and testes are part of this system. Say It Discuss With a partner, see how many organs you can name from each organ system. Interactive Textbook 351 Body Organization and Structure

4 Section 1 NSES LS 1a, 1d, 3a SECTION VOCABULARY homeostasis the maintenance of a constant internal state in a changing environment organ a collection of tissues that carry out a specialized function of the body tissue a group of similar cells that perform a common function 1. Compare How is an organ different from a tissue? 2. List Name five organ systems in the human body. 3. Explain Why is it important for your body to maintain homeostasis? 4. Infer What organ systems must work together to help a person eat and digest a piece of pizza? Give at least three systems. 5. Infer What organ systems must work together to help a person play a soccer game? Give at least four systems. 6. Apply Concepts Can an organ do the same job as an organ system? Explain your answer. 7. Identify Relationships How is the lymphatic system related to the cardiovascular system? Interactive Textbook 352 Body Organization and Structure

5 Life Science Answer Key continued 2. using up a resource without replacing it 3. Yes, if a renewable resource is used up faster than it is replaced, it can be depleted like a nonrenewable resource. For example, using fresh water faster than it can be replaced makes water a nonrenewable resource. SECTION 2 ENVIRONMENTAL SOLUTIONS 1. reduce, reuse, recycle 2. She is using her own bag while shopping, instead of plastic or paper bags. 3. Use fewer of them. 4. renewable 5. Reusing items reduces the amount of resources needed to make new items. 6. using the water again 7. It could pollute the air. 8. Each species has a unique role in an ecosystem. Biodiversity can protect against the spread of disease. 9. to increase the population of an endangered species 10. Recycling materials such as paper and wood reduces the amount of resources used to make new products. If fewer resources are needed, fewer habitats may be destroyed. 11. Answers may vary, but students should be able to explain their answers. 12. Answers will vary. Students could circle any of the items. 1. If something is biodegradable, it means that it can be broken down by living things, such as bacteria. 2. Some organisms, such as plants and filterfeeding animals, can remove many wastes from water. The water can then be used on crops, lawns, and golf courses. 3. to keep people informed about environmental problems and to help enforce environmental laws 4. Driving a car that uses hydrogen would help conserve nonrenewable resources such as oil. These cars also produce less air pollution. 5. glass, paper, wood, cardboard, plastic, aluminum 6. to maintain biodiversity by protecting individual species 7. Cloth napkins can be reused many times. Using cloth instead of paper helps reduce the amount of paper used. Chapter 22 Body Organization and Structure SECTION 1 BODY ORGANIZATION 1. a state of stable internal conditions 2. two or more tissues working together to do a job 3. The stomach digests some food, but it needs other organs in the digestive system to finish digestion. 4. respiratory 5. reproductive 1. An organ is made up of two or more tissues that work together to perform a function for the body. A tissue is a group of similar cells that perform a common function. 2. Answers will vary but should include any five of the following: integumentary, muscular, skeletal, cardiovascular, respiratory, reproductive, urinary, endocrine, nervous, digestive, lymphatic 3. If your body could not maintain homeostasis, many processes in your body would not work. 4. digestive, muscular, nervous, endocrine 5. muscular, skeletal, nervous, respiratory, cardiovascular 6. No, organs have jobs, but organs have to work together to do the job of an organ system. 7. The lymphatic system returns leaked fluids back to the blood vessels of the cardiovascular system. SECTION 2 THE SKELETAL SYSTEM 1. Circulatory system, because you wouldn t be able to make new blood cells. 2. compact and spongy 3. a flexible tissue that forms part of the skeleton 4. spongy bone, compact bone 5. a place where two or more bones meet 6. gliding, ball-and-socket, hinge 7. It cushions the ends of bones, where they meet. 1. to protect organs, to store minerals, to work with muscles to cause movement, to make blood cells 2. bones, cartilage, and the connective tissue that holds bones together Interactive Textbook Answer Key 24 Life Science

Chapter 22. Body Organization & Structure

Chapter 22. Body Organization & Structure Chapter 22 Body Organization & Structure Start-Up Activity Too Cold for Comfort Hold a few pieces of ice in one hand. Hold the ice until the cold is uncomfortable. Then release the ice into the dish. Compare