Paula Largacha
A muscle can only pull and can not push, it needs another muscle to pull it back in place. This works because as one muscle contracts and pulls the other muscle is relaxed. When you want to move that body part back then the relaxed muscle will contract and the contracted muscle relax. The motion can be performed because tendons atached to the muscle pull on the bones with tendons, moving a limb.
2. Identify the structures that make up a skeletal muscle. Include these terms: muscle fiber, fascicle, myofibrils, actin, myosin, sarcomere.
A skeletal muscle is made up of a mescle fiber which is a cylindrical muscle cell that contain many nuclei. A skeletal muscle is made up of many of this cells. then inside of fascicles or bundles of tissues, there are the myofibrils which are bundles of smaller units which are striped. microfibrils are made up of sarcomeres which are muscle fibers basic unit of action; this is the unit that contracts the muscle. They are composed of thin (made of actin, twisted in ropelike way) and thick (made of myosin in bumplike projection).
3. Identify at least 3 organ systems involved in a handshake. Describe WHAT each system contributes to the handshake.
Three organ systems working when you give a handshakes are the muscular system, the nervous system, and the circulatory system. The nervous system is the one in charge the brain decides a handshake should be made and uses nerves to make the muscular sytem start working. The muscular system contributes by moving muscles so that bones will move to make the handskake possible moving the bones. All the while the circulatory system has been working to send blood cells and oxygen to the hand muscles.
4. Explain how actin and myosin interact as a muscle cell contracts.
Myosin heads attach to thin filaments (actin) , after attaching they bend pulling muscle to the sarcomere then ATP attaches to the myosin heads release and attach at a new place until they overlap each other and reach the sarcomere.
