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Bones - Contenido educativo
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Fifth segment of Good Stress describes the different types of bones in the body and explains the purpose of the skeletal system. The Bones segment describes what bones are made out of and how bones interact with muscles in the body. The Bones segment discusses what people should do to maintain healthy bones. The fifth segment ends with a discussion of how much bone loss astronauts can expect when they spend time in space.
Uh, Dr. Sonia? Hi, RJ. Come on in. Take a seat. I understand you want to learn more
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about bones, their structure and function. I sure do. I want to be the best cross-country
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runner in my state, and knowing more about my body might actually be an advantage. And
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after meeting Leland Melvin, I want to learn more about astronauts and how their bones
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can be affected by spaceflight. Sure. I'd love to discuss your body's skeletal system
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with you. Students, working in groups, take a few minutes to answer the following questions.
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What does the skeletal system do? It may be helpful to sketch a picture. List some types
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of bones in your body and explain their function. What are some ways to keep your bones healthy?
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How are the skeletal and muscular systems related? It's now time to pause the program.
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Without the skeletal system, your body would collapse. Your skeleton has many functions.
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It provides shape and support, protects your internal organs like your brain, heart, and
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lungs, enables you to move, produces red blood cells, and stores important minerals until
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your body needs them. You have about 206 bones in your body. For example, your arm consists
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of the humerus, radius, and ulna. Your leg consists of the femur, patella, tibia, and
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fibula. All your bones are connected to the vertical column, or backbone, in some way.
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I mentioned earlier that the skeletal system enables you to move. Most of the body's bones
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are associated with muscles. The muscles pull on the bones to make the body move.
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So the muscles and bones in our bodies work as a system?
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That's a great observation, RJ. That's why we can't just learn about muscles without
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understanding about bones, and vice versa. Bones also store minerals, such as calcium
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and phosphorus. These minerals make the bones strong and hard. They're packed tightly together.
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In fact, bones are so strong that they can absorb more force without breaking than concrete
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or granite rock. And bones are much, much lighter.
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Is there anything else in bones besides calcium and phosphorus?
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Yes. Bones also contain living cells and tissues, such as blood and nerves. As you grow, new
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bone tissue is produced. Even after you are grown, your bones continue to form new bone
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tissue. So what does the inside of a bone look like?
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Well, for example, let's look at a femur, or thigh bone. The femur, which is the longest
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bone, connects the pelvic bones to the lower leg bones. Notice the thin, tough membrane
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that covers all of the bone except the ends. Blood vessels and nerves enter and leave the
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bone through the membrane. Beneath the membrane is a layer of compact bone, which is hard
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and dense. Just inside the compact bone is a layer of spongy bone. Spongy bone is found
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in the backbone and at the ends of the bones. Like a sponge, spongy bone has many small
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spaces within it. This structure makes spongy bone lightweight but strong. The spaces in
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bone contain a soft, connected tissue called marrow.
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Because my leg was immobilized for a period of time, does that mean that the bones of
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my leg were affected? Sure your bones were affected, not in terms
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of size, but in terms of bone density. So, RJ, do you have any idea how to keep your
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bones healthy? Well, I believe good nutrition and exercise
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is the key to strong and healthy bones. Way to go, RJ. You're pretty good.
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I learned about good nutrition and exercise from the NASA Connect program. Better health
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from space to earth. Go to the NASA Connect website to learn more.
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You know, RJ, a well-balanced diet contains enough calcium and phosphorus to keep your
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bones strong while they're still growing. Meats, whole grains, and leafy green vegetables
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are all excellent sources of both minerals. Dairy products, including milk, are excellent
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sources of calcium. Exercise is also important to help bones become stronger and denser.
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But you don't have a problem with that because you work out all the time.
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I also learned that it's important to develop good nutrition and exercise habits when you're
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in space. That's true. It's very important because your body's bones are still growing.
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Beth Shepard told me earlier that astronauts' bones become weaker and smaller after they
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return from space. How much do they lose? Well, it depends on a number of factors, such
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as spaceflight duration, amount of exercise in space, nutrition, and body chemistry. Most
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of the bone loss occurs in the lower portion of the body, primarily from weight-bearing
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bones. One study we conducted on astronauts on the ISS showed that the mean, or average,
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bone mineral loss in the hip portion of the femur, or spongy bone, ranged from 1 to 2.5
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percent per month, about 1.35 percent per month in the pelvic region, and 1 percent
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per month in the lower back, or lumbar region. That's really interesting. So what happens
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when astronauts go to Mars and beyond? If an astronaut loses about 1 percent of their
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bone mineral in the lower back per month, then that means that he or she will lose roughly
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12 percent over a year. Since the current missions haven't lasted that long, we don't
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actually know, but it is likely. And therefore, we need to conduct more research to know for
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certain. You know, the more we can learn about how our bodies function in space, the closer
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we get to developing countermeasures that will significantly reduce the effects of bone
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loss and muscle loss while in space. Space research is important because it helps us
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to understand how our bodies function here on Earth. It is another tool to help us combat
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diseases, such as the bone disease osteoporosis. Thanks, Dr. Sonia. If you ever need assistance
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with your research, just call me. I'll do that, RJ, and good luck with your training.
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Okay, take it easy.
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I think we'll be hearing more from RJ in the years to come. And hopefully, we'll be hearing
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more from you. Don't forget to check out this program's Student Challenge, which can be
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found on the NASA Connect website. Well, guys, that wraps up another episode of NASA Connect.
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We'd like to thank everyone who helped make this program possible. Got a comment, question,
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or suggestion? Well, then email them to connect at larp.nasa.gov. So until next time, stay
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connected to math, science, technology, and NASA. And remember, the good stress in life.
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See you then.
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- Idioma/s:
- Materias:
- Matemáticas
- Niveles educativos:
- ▼ Mostrar / ocultar niveles
- Nivel Intermedio
- Autor/es:
- NASA LaRC Office of Education
- Subido por:
- EducaMadrid
- Licencia:
- Reconocimiento - No comercial - Sin obra derivada
- Visualizaciones:
- 571
- Fecha:
- 28 de mayo de 2007 - 16:54
- Visibilidad:
- Público
- Enlace Relacionado:
- NASAs center for distance learning
- Duración:
- 08′ 04″
- Relación de aspecto:
- 4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
- Resolución:
- 480x360 píxeles
- Tamaño:
- 48.56 MBytes
