Companion Slide Set for The Science of Muscles

Companion Slide Set for The Science of Muscles and Bones Teacher’s Guide was developed by Baylor College of Medicine with support from the National Space Biomedical Research Institute. Bio. Ed Online

Simulating Effects of Microgravity n n n To practice for working in space, astronauts work under water in a giant swimming pool. Astronauts wear weighted suits to prevent them from sinking or rising. This condition, which is called Astronaut Dave Williams participates in an underwater “neutral buoyancy, ” simulation of extravehicular activity in the Neutral Buoyancy reduces the sensation of Laboratory near Johnson Space Center in Houston. gravity and simulates the feeling of working in microgravity. However, gravity is still acting on the astronauts. If they work upside down, for example, blood still rushes to their heads. Photo courtesy © Josh Hillman. of NASA. Bio. Ed Online www. Bio. Ed. Online. org

Endoskeletons n n n MRI of a human knee (side view) in a 44 year old male. The bones, darkest gray, are clearly defined. Endoskeletons are located inside the body. In endoskeletons, bones are connected across joints by tough fibrous ligaments. Muscles, which usually are attached to bones by tendons, make movement possible and also help support the body. Photo by Nuada Medical © Wellcome Images. Bio. Ed Online www. Bio. Ed. Online. org

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Hollow vs. Solid n n Hollow, air-filled bones lighten the weight of a bird’s skeleton. In some species of birds, the air-filled skeleton is so lightweight that the bird's feathers weigh more than its entire skeleton! Photo © Renn Tumlison, Henderson State University. Bio. Ed Online www. Bio. Ed. Online. org

How Do Arm Muscles Move? This muscle brings the forearm up. This muscle brings the forearm down Photo © Arthur D. Forman. Bio. Ed Online Illustrations © William & Wilkins. All Rights Reserved. www. Bio. Ed. Online. org

Joints in the Human Body Wrist and fingers Knee Hip Elbow Photo © Arthur D. Forman. Bio. Ed Online Food ankle Illustrations © William & Wilkins. All Rights Reserved. www. Bio. Ed. Online. org

Muscles and Tendons in the Hand n There almost no muscles in your fingers. The muscles that move your fingers are in your arms. These muscles have very long tendons that attach to the bones in your fingers. Other muscles are located in the palm of your hand. ) Photo © Arthur D. Forman. Bio. Ed Online Tendons (blue) Hand muscles (red) Illustration © William & Wilkins. All Rights Reserved. www. Bio. Ed. Online. org

Arm Model Completed arm model Working Arm Model Photo © Arthur D. Forman. Bio. Ed Online Illustrations by M. S. Young © Baylor College of Medicine. www. Bio. Ed. Online. org

Strength in Numbers n n n Skeletal muscles (the ones responsible for movement of the body) are made of bundles of progressively smaller fibers. The largest fiber bundles can be pulled apart into smaller bundles of fibers. Within these bundles are numerous muscle cells (also called fibers). Each muscle cell is filled with hundreds of even smaller strands. Added together, all of the minute contractions shorten the length of the entire muscle. Photo © Arthur D. Forman. Bio. Ed Online Illustration © William & Wilkins. All Rights Reserved. www. Bio. Ed. Online. org

Muscle Loss n n n Muscle fibers (blue) taken from an astronaut before going to work in space. Muscle fibers (red) taken from the same astronaut after returning to Earth. The white lipid droplets are a result of spending time in microgravity. The droplets interfere with normal muscle function. Both astronauts in orbit and patients on Earth fighting musclewasting diseases need help to prevent muscle loss. Photo © Arthur D. Forman. Bio. Ed Online Courtesy of NASA. www. Bio. Ed. Online. org