Health Blog!

Welcome students to our class blog. We will be using this space for class discussions to examine, evaluate, and share knowledge. Discussions provide opportunities for students to think critically on the topics we will be learning about in Health class. Concepts, assignments, and readings will be used as the basis for our discussions to create a positive learning community in which students are willing to share their ideas and to accept constructive criticism from their peers.

Wednesday, January 5, 2011

Concept check 27.5
1. Explain how muscles work in pairs in moving limbs.
For each muscle that contracts, there is an opposing muscle that relaxes. However, the opposing muscle can also contract and pull the bone back in the opposite direction. For example when a bass drummer beats the drum, his biceps contracts and his triceps relaxes. When he pulls his arms away from the drum, the opposite occurs.

2. Identify the structures that make up a skeletal muscle. Include these terms: muscle fiber, fascicle, myofibrils, actin, myosin, sarcomere.
Skeletal muscle consists of parallel muscle fibers along with nerves and blood vessels. Inside a muscle fiber are bundles of smaller units called myofibrils.A single myofibril consists of repeating units called sarcomeres. Each sarcomere is composed of two kinds of filaments, thin and thick. The thin filaments are composed of the protein actin and have a twisted, rope-like structure. The thick filaments are composed of the protein myosin and have bump-like projections called myosin heads.

3. Identify at least 3 organ systems involved in a handshake. Describe WHAT each system contributes to the handshake.
First the eyes sense the presence of the person. There it sends messages to your brain, with acts as a control center. The brain sends messages to the muscles to initiate the handshake. They respond by coordinating contractions and relaxations of different muscles. Blood cells travel throughout all the process providing a constant supply of nutrients and oxygen to hand muscles. 


4. Explain how actin and myosin interact as a muscle cell contracts.
 ATP plays an important role in this process. In each contraction myosin heads bind to thin filaments. Next, they bend, pulling the thin filaments toward the center of the sarcomere. ATP then binds to each myosin head, releasing it from the thin filament. The myosin head is now free to attach at a new spot and further pull the thin filament along. Filaments themselves don't get shorter, but their overlap increases as they slide across one another. The sarcomere shortens. The process can continue until the sarcomere is fully contracted. As the sarcomeres of many muscle fibers shorten together, the entire muscle contracts.


BY: MARTHA EMILIA MENA
Posted by at

5 comments:

  1. TheaJanuary 11, 2011 at 3:39 PM

    Your answers are complete and very specific, they helped me understand more about the subject.

    ReplyDelete
  2. Daniela CazarJanuary 11, 2011 at 3:48 PM

    I liked your answers because they gave a lot of information. The only problem i found was that i didn't know which organ system where mentioned in question 3. Be more specific.

    ReplyDelete
  3. Luis RodriguezJanuary 11, 2011 at 4:55 PM

    Your answers are well explain and you demonstrate you know about the topic very well it is explained in a consise way.

    ReplyDelete
  4. UnknownJanuary 11, 2011 at 5:55 PM

    Hi Martha Emilia! I think your answers very thought through. Especially in question number 3 instead of just naming the parts involced by explaining the involvement of each part I understood better how the interaction works! Great Job!

    ReplyDelete
  5. MaferGranjaJanuary 12, 2011 at 5:37 PM

    Hi martha!
    i thought your answers were pretty long, but explained each question throughly. i liked answer number one when you talk about the drum jajaja. i thought that was a good example.
    thanks for making me understand it better.
    mafer

    ReplyDelete

Subscribe to: Post Comments (Atom)